A Systematic Review of the Concrete Durability Incorporating Recycled Glass

Abstract

This systematic literature review (SLR) aims to present and analyze the recent research on the effect of recycled glass (RG) on the durability of concrete applications in terms of transport properties, chemical attack, alkali-silica reaction (ASR), and freeze/thaw (FT). RG could be utilized in concrete as a replacement or addition in three forms, namely glass powder (GP), glass aggregate (GA), and glass fiber (GF). The methodology of this study was based on a criterion for the selection process of reviewed studies to assess and synthesize the knowledge of the durability of RG in concrete. The articles were assessed and screened, then 114 review articles were selected. The direction of utilization of RG in concrete depends on the type, particle size, and pozzolanic performance. The valorization of RG had a positive impact on the durability of concrete; however, the mutual synergy of multiple substitutions with glass also had better results. Nowadays, fine glass aggregate (FGA) could be promoted to be used as a partial substitute for sand due to the easiness of recycling. Furthermore, GF is strongly encouraged to be used in fiber concrete. An analytical framework that highlights the durability improvement of glass-modified concrete is presented. The results suggested that it is technically feasible to utilize glass as a part of concrete in the production of durable concrete. It provides a higher resistance to transport properties and chemical attacks by providing an extended lifespan. In addition, RG plays a great role in FT action in cold climates while it does not have a significant impact on ASR, provided refinement of glass results in the reduction of ASR and thus overcomes the expansion and cracks of concrete. However, up to 20% GP and up to 30% fine glass aggregate (FGA) could be replaced with cement and aggregate, respectively, to achieve a positive effect on durability based on the W/C ratio provided, not compromising the strength.

1. Introduction

Cement is the most frequently utilized building ingredient in construction engineering. It is liable for a high content of CO₂ discharge during the calcination process of cement production and the decomposition of calcium carbonate [1,2,3]. The main pollutants emitted from the cement industry are dust, carbon dioxide, nitrogen oxide, and sulfur oxides which are very dangerous to our environment [4]. These pollutants cause air pollution and lead to the greenhouse effect. For the time being, the biological and geological approach could be adopted for CO₂ sequestration [5]. In addition, obtaining aggregates from quarries and rivers sides lead to the depletion of natural resources. Excessive sand mining causes the degradation of rivers, and this can lead to extreme flooding causing a threat to biodiversity [6,7].

Consequently, all of the above-mentioned leads to global warming and environmental pollution. The environmental problems have been exacerbated by accumulation of waste glass (WG) resulting from glass’s daily uses. This WG disposed in landfills will eventually form a threat to the environment if no recycling and commercial gains plans are introduced. The rising environmental challenges, increasing scarcity of landfills, and depleting sources of natural aggregate (NA) in some regions are the main factors that promote the recycling process to produce sustainable concrete. As glass is considered one of the most versatile substances and one of the main components of solid waste, the recycling process with limited market value is believed to be an important step towards sustainable construction practices [8] and an attractive alternative in concrete production. Thus, the evolution use of RG as a partial substitute for cement and aggregate is a feasible approach nowadays. While the cement industry is considered one of the largest CO₂ producers and energy-consuming manufacturers, utilizing cement as a replacement material will save the environment by reducing CO₂ emission. This coincides with present research that adopts the biological approach in which CO₂ is sequestrated into bio-foamed concrete bricks [5]. In addition, using glass as fine aggregate provides a better solution for its disposal problem and prevents the depletion of natural resources like river sand [9]. Thus, it reduces the quantity of aggregate consumption in concrete.

Glass is a product of the supercooling of a melted liquid mixture of selected raw materials, which are heated at extremely high temperatures consisting primarily of silicate and other oxides such as silicon dioxide, sodium oxide, and calcium oxide to a rigid condition [10,11]. Glass has attractive properties that can be used in concrete in different forms. It is an inorganic, inert, non-metallic, non-biodegradable, and synthetic material that is neither decomposed in nature nor incinerated [9,12,13,14]. It is characterized by high abrasion resistance, a translucent surface, high toughness, in-combustible characteristics, and high ductility at high temperatures [14,15].

The uses of glass products have increased tremendously, resulting in large amounts of WG [16]. Glass is a 100% recyclable material with high performance and unique aesthetic properties, which make it suitable for different uses [17] because its utilization as a byproduct will provide cost savings and protection to the environment. However, the recycling rate of WG is low due to contamination as the main reason that affects glass melting conditions of recyclable glass due to the chemical composition incompatibility [18]. For instance, the expanded GA is the product of RG, which is treated and granulated at approximately 900 ◦C temperature [19]. Consequently, only some of the glass could be recycled into new glass in the glass manufacturing industry because of impurities, cost, or mixed colors [20]. It accounts for only 25% and most of it is landfilled [21].

The gains that can be obtained from the utilization of glass are more than what can be expected. The use of WG in the manufacturing of new glass reduces energy consumption, raw materials use, and wear and tear on machinery [16]. Glass is manufactured in various forms depending on the requirement of the glass industry. It can be found in many forms, including container glass, flat glass such as windows, bulb glass, and cathode ray tube (CRT) glass [22]. Moreover, glass is manufactured in three different colors, mostly green, brown, and colorless [23].

Glass is an amorphous material with a high silica (SiO₂) content, and it could become pozzolanic when the particle size is less than 75 µm [24]. Glass product formations are always in different grades, and the most important glass type is soda-lime, representing the largest percentage of WG [21] since it is the most commonly used and disposed of in urban environments [25]. Silica material in glass exceeds 70%, and an appreciable amount of lime (CaO) is over 11%. However, it contains a significant amount of sodium oxide (Na₂O), estimated at over 12%. For example, typical soda bottle glass contains around 70% silica and 10~15% alkali, and the remainder is made of other elemental components [26]; in contrast, CRT glass contains silica (50–60%) and other different materials such as barium oxide and lead oxide [27]. As crushed glass contains large quantities of silicon and calcium with an amorphous structure, it has the possibility to act as a pozzolanic or even a cementitious material [20]. When glass is incorporated in concrete, it is cleaned out of the dirt materials and impurities and crushed in specific machines, and then it is ground into different particle sizes of coarse and fine-sized glass and powder form using sieve analysis. The use of WG in the manufacturing of concrete is a favorable practice that could help in absorbing a considerable quantity of WG [28].

Previous studies have investigated the effect of adding glass on the durability of concrete, either separately or mixed with pozzolanic materials. Most of them indicated improved properties of concrete depending on the finesses and replacement level. Glass may be added in crushed form or in powder form along with the addition of plasticizer admixtures or without the addition of any of the alternate materials in the concrete [29]. Furthermore, GF is manufactured from glass. It is relatively economical [30] and is utilized in glass-reinforced fiber concrete (GRFC) as a composite material basically manufactured with cement, water, and fine aggregate [31] in which is dispersed polymer and often mineral additives [32]. Adding this alternative material needs to be deeply reviewed in order to justify and emphasize the effectiveness of using RG as a cement or as an aggregate replacement. Adding glass to concrete leads to some strength and durability properties. It is possible to add glass to the concrete by replacing either of the ingredients partially in any glass form [33]. Several studies on RG as a partial replacement for Portland cement (PC) or NA in concrete have been reported in terms of workability, strength, and microstructural properties. However, few studies have reviewed the durability properties of concrete incorporating RG as cement or aggregate replacements. Durability is of great importance for concrete performance since it is not specified only by its fresh or mechanical properties.

This paper aims to provide a comprehensive review of previous studies to investigate the effect of RG on the durability of concrete. The most significant durability indicators of the respective testing program in previous studies were analyzed and discussed. Based on the current research trends, the main objectives of this article are to highlight the researchers’ efforts in evaluating the effect of RG as cement and aggregate substitute on the durability of concrete, map the research attitude from the literature, fill the gap of research needed for upcoming studies, and highlights the future development to utilize RG as an alternative material to obtain durable concrete.

2. Review Significance

Great benefits can be obtained from developing SLR in this specific research area. The review of the recently published studies reflects a clear vision of the ongoing development in this aspect. The SLR helps conduct comparisons between the studies on a topic from several viewpoints of researchers to get in-depth feedback. Despite the existence of research on the recycling and utilization of glass in building materials applications, there is a clear lack of research papers that include an SLR of research focusing on the effect of glass on the durability of concrete.

Over the years, WG has widely been used to make modified concretes [34]. During the recent period, the utilization of glass, whether separated or combined with pozzolanic materials, for producing sustainable concrete has been one of the significant research topics and practical interests since the recycling rate of WG is quite low in many countries compared to the rate of waste generation [35]. The use of glass as an aggregate in concrete has great potential for future high-quality concrete development [17]. There is an increased interest and global trend in recycling and utilization of RG in concrete to enhance the durability of concrete using sustainable materials. Furthermore, there are a lot of efforts to investigate the durability of concrete replaced with glass. The majority of recent review studies have focused on the workability of fresh concrete and the mechanical properties of hardened concrete, while few studies have reviewed the durability aspects of concrete replaced with glass and focused on special types and forms of glass without conducting SLR of the effect of glass on the durability of concrete.

In spite of the numerous efforts from researchers, many recent studies have revealed that there is still a gap regarding the impacts and ratios of glass on the durability of structural concrete. Furthermore, to the best of the authors’ knowledge, there is a lack of SLR on this topic, which highlights the previous achievements, and the future challenges of the durability of concrete containing all forms of glass as the improvement of durability properties of concrete materials deserve special attention in order to extend the service life of structures [36]. This SLR work on the durability of concrete replaced with glass mainly focuses on identifying the prevailing achievements and highlighting the research gaps for future studies. It presents an up-to-date literature review on the durability properties of concrete that is replaced only with glass or combined with pozzolanic materials.

Moreover, this study presents the relationship between the optimum of glass as one replacement material or various replacements of glass and pozzolanic materials. This will facilitate the utilization of optimum ratios of glass in terms of types and fineness and direct the future research of glass in concrete for an effective improvement in the durability of concrete in order to fill these research gaps. Conclusions on the role and applicability of RG in concrete were subsequently deduced from the SLR.

3. Methodology and Bibliometric Mapping

The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). CONSORT 2010 checklist was adopted to evaluate the effect of recycled glass on durability of concrete. It allows to assess the appropriateness of methods and to examine the results of previous studies (see Supplementary Material). The first stage is composed of two main steps, namely, the research question and search strategy. Then records screening involves filtration to ensure relevance, followed by extraction to evaluate the data by applying quality assessment criteria. Finally, data synthesis involves a detailed analysis of data to produce a concluding set of subsequent procedures.

The methodology of this study is based on an SLR in the selection process of reviewed studies to assess and synthesize the knowledge of the effect of RG on the durability of concrete. The data and the results of the reviewed articles were analyzed and discussed systematically.

3.1. Research Question

This study mainly focuses on the effects of various forms of glass as a replacement for cement and aggregate being separated or blended with pozzolanic materials on the durability of concrete. The major question of this study is to review the recent research on the effect of RG on the durability of concrete applications. This focus stems from the rising understanding of the environmental impact of the construction industry to obtain sustainable concrete. The principal research question that has been developed to fulfill the main question is: What is the role of RG in the durability of concrete application, and how do researchers approach this subject? Based on the main research question, four specific research questions are outlined:

• What are the forms of glass under SLR utilized for the durability of concrete?
• What are the durability-related properties under SLR of adding RG to concrete?
• How could RG affect each durability property of concrete and its recent development?
• How could combined RG and pozzolanic materials affect each durability property of concrete and its recent development?

3.2. Bibliometric Analysis by Co-Occurrence (Author Keywords)

Bibliometric analysis is used as a scientific metric to give an indicator that reflects the importance of the research and highlights the research gap of this review. Bibliometric maps were analyzed by 114 articles from the Scopus database based on different types of limitations as follows: keywords, last 10 years, type of documents (review and journal papers), and English language.

The keywords used were (“Concrete”), (“Durability”), and (“Glass”), respectively. The number of authors’ keywords with 3 occurrences, total links strength, and clusters were 41, 284, and 7, respectively. The authors’ keywords that occurred 5 times and more were 16, as shown in

Table 1. The author’s keywords occurred more than 3 times in VOS viewer software.

Keyword	Occurrences	Total Link Strength
durability	52	97
concrete	19	47
compressive strength	20	38
waste glass	13	36
mechanical properties	14	28
alkali-silica reaction	9	23
strength	10	23
glass powder	13	22
recycling	8	20
fly ash	6	16
glass fiber	8	13
microstructure	9	13
sustainability	6	12
flexural strength	6	11
silica fume	5	11
glass aggregate	3	10
sustainable concrete	4	10
waste glass powder	5	10
waste management	3	10
freeze-thaw resistance	3	9
tensile strength	4	9
glass	4	8

. It can be seen that most of the researchers focused on durability of the concrete as well as compressive strength. Therefore, the highest occurrence of the keywords was for durability, compressive strength, and concrete by 52, 20, and 19, respectively. “Glass” occurred 4 times as a pure material, as shown in Table 1. However, waste glass occurred 13 times as author keywords used to replace cement or aggregate in concrete. This finding can give an indicator that glass was used as a replacement material in concrete; however, it has not been used in a wide range worldwide.

The network visualization in Figure 1A represents the items by their labels and circles. The size of the circles of the mentioned top 5 authors’ keywords represents the weight of the item. The large circle represents the higher weight of the items. The durability and compressive strength of concrete are of the most concern among the authors worldwide. Figure 1B highlights the history of each author keywords from 2012 to 2021, which can be differentiated by color. Glass combined with other words, as a keyword is mentioned in the last years specifically in 2019 and 2020, which indicates the applications of glass have increased, particularly waste glass and glass powder, as shown in Figure 1A,B. This finding can give a clear vision of the future applications of glass in concrete to improve durability and compressive strength. This finding strongly supports the aim of this review and the future directions of the applications of glass in concrete.

3.3. Search Strategies

This study has adopted a comprehensive search for previous studies. The Scopus advanced search was conducted to collect the most relevant established data on this topic, limited to the papers published in the last 10 years, from 2012 to 2021. The scope of each article was determined by searching the keywords in the title and abstract, and then the most relevant literature was selected in this review article. The durability property of concrete containing RG was selected in order to limit large-volume studies and several research works on concrete properties. A period of 10 years was chosen because the topic is of intense research activity. The search lies on the Scopus database to obtain the related published articles based on a predefined criterion. The terms “durability”, “glass”, and “concrete” are the main keywords.

TITLE-ABS-KEY (“durability” and “glass” and “concrete”)

3.4. Selection Process

The initial list of 1593 studies was filtered and analyzed to ensure relevance. Several steps were involved in this process. Initially, the titles were assessed for relevance, and the contents were briefly scanned to ensure relevance to the issues under investigation. They were further assessed against the following requirements: period of publication (2012–2021), document type (article and review), and language (English). The SLR was conducted on articles published between 1 January 2012 and 31 December 2021.

3.5. Data Extraction

In the screening stage, 615 articles were assessed based on the title, abstract, and keywords of the articles that were compatible and relevant to the scope of the study, and the contents were briefly scanned based on the validity of the study data and their related contribution to ensure their relevance to the current review [37]. The inclusion criterion was based on a checklist of questions related to the application of the RG in concrete and the influence of RG on the durability property of the concrete (see

Table 2. Study inclusion criteria quality checklist.

ID	Checklist Question
Q1	Are the objectives of the study clearly stated?
Q2	Is the methodology (experiment program) used properly for the subject?
Q3	Is the experiments results clear and useful for the subject?

). The articles were given a score based on their capability to provide answers to specific questions. The process involved allocating a score based on how closely the answers matched the research questions. The scoring system was “Include = 2”, “May be = 1”, or “Exclude = 0”. A total relevance score was produced at the end. An “acceptable quality” score was then allocated, and other studies must fall within this range to be accepted. The qualifying studies were also required to have a score greater than 50% of the percentage score. This system excluded 501 articles, given their lack of adherence to the minimum quality assessment score. Consequently, 114 articles cited from the initially reviewed articles within limitation methods, and 11 out of the limitation were selected as outlined in Figure 2. However, there are some articles used in this review selected out of the limitation (some below 2009, while others are not based on chosen keywords).

4. Results

4.1. Forms of Glass Utilized for Durability of Concrete

Glass has a promising recycling potential and can be repeatedly recycled without a change in its physical and chemical properties [38] despite the challenging issue of recycling. Recycling WG is a complex process [39,40] comprising primarily cleaning, separation of colors from clear glass, and crushing to the appropriate particle size. However, refining WG at the micrometric level is a great solution to valorize WG [41]. Glass is mainly characterized by soda lime, lead, vitreous silica, borosilicate, alkali silicates, aluminosilicate, and barium glasses [42]. Regarding chemical composition, WG is categorized into (1) soda-lime glass, (2) lead glass, (3) borosilicate glass, and (4) electric glass [40]. Glass is produced in a wide variety of colors (e.g., amber, clear, blue, and green) depending on different melting points of each glass color [26].

On the other hand, GF is produced as a by-product that does not meet the physical specification requirements and is discarded as off-spec GF. Moreover, GF could be produced from WG as a raw material used in the production of thermal and sound insulation panels, mats, and lagging [43]. GF has more resistance to temperature, corrosion resistance, non-flammability, and good strength in tension [44]. GF is three times lighter than steel fiber [45]. Accordingly, those factors attract the attention of researchers to investigate the use of glass in concrete. Type E glass has a low-alkali form more than 95% of the produced GF [46], whereas ZrO₂ alki-resistant glass (AR-glass) demonstrates higher alkaline resistance and is preferred to fibers made of soda-lime glass [32,47].

The bulk density of glass differs based on the type, manufacturing method, and recycling method. However, the bulk density of GA is lower than that of typical NA. The previous studies indicated that the specific gravity of all types of glass ranged from 2.265–2.60. It is observed through SEM that glass particles seem more angular, denser, and more prismatically shaped compared with cement [48]. In addition, glass has a negligible water absorption capacity of 0.07% [49].

After reviewing the literature, it has been observed that glass is used in concrete in three forms, namely, glass replacing cement, glass replacing aggregate, and glass fibers as an addition. Figure 3 illustrates the types of glass used in concrete as reported in the literature. There is a clear distinction in terms of durability performance of using glass as a replacement to cement or aggregate depending on the form and size [50]. Producing concrete modified with glass is approximately similar to conventional concrete for all stages: preparation, mixing, and curing. Glass substitute in concrete could be either replacement of fine and coarse aggregate, which is called GA, or replacement of cement, which is called GP. WG sludge which is part of GP is a byproduct of a glass plant where glass panels are cut and polished for manufacturing processes [51].

4.2. Durability-Related Properties of Recycled Glass in Concrete

This part focuses on the presentation and analysis of the results obtained from the experimental program for durability-related properties of RG in concrete. Figure 4 indicates the reviewed durability properties, both internal durability, including ASR, and external durability, including transport properties, chemical attack, and FT.

4.2.1. Transport Property

The transport property is the most important estimation of the durability of concrete since higher transport into the concrete will lead to fast penetration of harmful chemicals that can react with its constituents and change the properties of concrete. The reviewed transport property of glass in concrete is represented as follows: water transport, chloride transport, oxygen permeability, electrical resistivity, and carbonation. Among the aforementioned properties, water transport is the most frequent in previous studies, which comprises water absorption (WA), sorptivity, water permeability or water penetration (WP), and water porosity. WA is the most common water transport property tested by researchers, as it is an implicit estimate of the durability of concrete. It represents the percent of water-permeable voids in concrete, and both strength properties and permeability-resistance against chemicals largely depend on the voids’ ratio of concrete [45]. Some of those properties are associated with each other. Specifically, WA indicates the accessible porosity of concrete depending on voids volume, volume of porous aggregates, and binder properties. Moreover, the permeability of concrete structure relates to the degree of difficulty of diffusion, permeate, or migration of gas and liquid when they are under pressure reflecting material pore size, quantity, distribution, and connectivity status [52]. Chloride transport comprises rapid chloride penetration test (RCPT), chloride penetration (CP), and chloride diffusion (migration). Figure 5 depicts the transport mechanism of expanded glass in ultra-high-performance concrete. The closed sintered skin of expanded glass interrupted the capillary pore system and thus the transport processes, making the material more resistant than NA to chemical or physical attack [53].

The permeability test is an important indicator of quality concrete in terms of water or oxygen. It expresses the ease of movement of fluids through a porous structure under an externally applied pressure [54]. According to carbonation, it could be tested by splitting the specimen into two, and phenolphthalein indicator solution was sprayed on the freshly broken specimens according to BS 1881: Part 201: 1986 exposed to atmospheric CO₂ [55]. In general, Transport properties can influence each other. For example, the electrical resistivity test provides a rapid indication of the likely resistance of concrete to CP and the likely subsequent rate of corrosion [54,56,57]. Nevertheless, electrical resistivity is much easier and faster than RCPT [58]. Water can transport salts, such as magnesium chloride, calcium chloride, and sodium chloride, which affect the service life of concrete structures [59].

4.2.2. Chemical Attack

The chemical attack comprises exposing concrete to different chemicals. An aggressive environment such as seawater is a clear example of chemicals affecting concrete in terms of chlorides, sulfates, and acids. The presence of calcium hydroxide is known to have a deleterious effect on the sulfate and acid attack.

Sulfate comprises different types, namely, calcium, sodium, magnesium, and potassium. The chemical reaction between sulfate and aluminate components produces ettringite and gypsum, which lead to expansion and form salt in hardened concrete, making an increase in the internal pressure [60]. The sulfate attack resistances could be evaluated based on visual appearance, mass change, strength, ultrasonic pulse velocity, mineralogy, and microstructure [61]. However, the visual inspection demonstrates random cracks, which are responsible for the penetration of additional sulfates, causing the deterioration of concrete. The mass and volume loss of concrete will take place due to the accumulation of expansive products leading to strength loss.

Sulfates can react with calcium hydroxide existing inside the hardened concrete resulting in calcium sulfate. For example, magnesium sulfate can react with calcium hydroxide and continues with magnesium silicate hydrate (M-S-H) formation according to Equations (1) and (2). Meantime, other by-products are produced in the expansion of the samples [60]:

Mg₂SO₄ + Ca(OH)₂ + 2H₂O → CaSO₄.2H₂O + 2MG(OH)₂

(1)

C-S-H + Mg₂SO₄ + 2H₂O → CaSO₄.2H₂O + M-S-H

(2)

In turn, reaction with calcium aluminates forms calcium sulfoaluminate indicated as ettringite, which causes internal pressure leading to concrete cracks. Formation of ettringite is an expansive process and can lead to cracking and a resultant loss of strength in the samples [62]. The following equation clarifies the mechanism of ettringite formation.

4CaO·Al₂O₃·19H₂O + 3(CaSO₄.2H₂O) + 16H₂O₃ → CaO·Al₂O₃·3CaSO₄·32H₂O + 3(CaSO₄·2H₂O) + Ca(OH)₂

(3)

C-S-H + (CaSO₄·2H₂O) → (CaSO₄·2H₂O) + N-S-H

(4)

Acids can react aggressively with calcium hydroxide in the hydration of products and leads to the production of salts and gypsum. This creates expansions and internal pressure in concrete, which ultimately leads to degradation. Then, gypsum reacts with the calcium aluminate and forms more expansive products known as ettringite [35,63]. Sulfuric acid (H₂SO₄) is the acid most commonly used in the review to check the resistance of concrete. Visual examination revealed that sulfuric acid attacks the sharp corners by exfoliating the corners and then turning them into a rounded shape forming a white layer. Due to the very low pH value, H₂SO₄ is the most aggressive and destructive acid that easily reacts with calcium hydroxide and produces calcium salt, which consequently leads to rapid degradation of concrete. [63]. The following equations illustrate the mechanism of sulfuric acid reaction [64].

Ca(OH)₂ + H₂SO₄ → CaSO₄·2H₂O

(5)

CaSiO₂·2H₂O + H₂SO₄ → CaSO₄ + Si(OH)₄ + H₂O

(6)

3CaO:Al₂O₃·12H₂O + 3)CaSO₄·2H₂O) + 14H₂O → 3CaO:Al₂O₃:3CaSO₄:32H₂O

(7)

Absorption of acidic solution results into formation of products like ettringite and gypsum as mentioned in Equations (8) and (9) [65].

CAH + SO₄²⁻ → Ca6 Al₂(SO₄)₃(OH)₁₂.26H₂O

(8)

Ca(OH)2SO₄²⁻ + 2H⁺ → +CaSO₄·2H₂O

(9)

4.2.3. Freeze-Thaw Property (FT)

The FT property is very critical for a concrete building located in very cold areas [36]. FT damage is caused by excessive water on the surface of or within voids/pores of concrete through the capillary property. When concrete is saturated with water and the temperature drops, the H₂O molecules start to freeze and then theyexpand from their original volume producing pressure in the pores of the concrete [66]. Consequently, the concrete will be damaged through surface spalling and internal cracking. The air voids within the concrete accommodate the swelling and expansion of water volume, thereby relieving the internal stress, which might result in cracking and spalling. In addition, the higher compressive strength has an effect on preventing damage [67].

The amount of FT damage was evaluated by measuring the fundamental transverse frequency of concrete prisms every 25 cycles of FT exposure. The fundamental transverse frequency of simply supported concrete prisms was performed according to ASTM C215-08. The relative dynamic modulus of elasticity (RDME) was calculated based on the fundamental transverse frequency measure using the following equation [66,67,68].

$$\mathrm{RD}=\left(\frac{{\mathrm{f}}_{\mathrm{n}}^2}{{\mathrm{f}}_{\mathrm{o}}^2}\right)\times 100$$

(10)

where RD: relative dynamic modulus of elasticity (%), f_n: fundamental transverse frequency after n cycles of FT exposure, and f_o: initial fundamental transverse frequency at o FT cycles.

The durability factor was calculated using the following equation (ASTM C 666-03).

$$\mathrm{DF}=\mathrm{RD}\frac{\mathrm{N}}{\mathrm{M}}$$

(11)

where N: the number of cycles at which RD reaches the specified minimum value for discontinuing the test or the specified number of cycles at which the exposure is to be terminated, whichever is less, and M: the specified number of cycles at which the exposure is to be terminated.

According to the frost-resistant criteria for the Polish standard PN-B-06250:1988, concrete is classified as frost resistant by satisfying the following: the weight variation must not exceed 5%, the loss of compressive strength must not be higher than 20%, and cracks must not occur during the test [69].

4.2.4. Alkali-Silica Reaction (ASR)

ASR is a major durability problem in concrete structures. ASR is a chemical reaction that occurs between the reactive amorphous silica from the NA and the alkalis in cement in the presence of moisture [70]. This reaction causes undue expansion and cracks in hardened concrete that, over time, results in deterioration. The ASR of concrete depends on the type, size, and replacement ratio of RG.

Most of the reviewed studies have carried out an accelerated ASR test in accordance with ASTM C 1260. A zero reading was taken after storing the prism samples in 80 °C distilled water for 24 h. The samples were then transferred and immersed in 1N sodium hydroxide solution at 80 °C until testing time. The measurements of ASR expansion were taken at 14 days. Moreover, durability against ASR was assessed by autoclaving method, SEM-EDS, and optical microscopic to examine the concrete-based composite stability [71]. The alkali level depends on the type and fineness of glass. For example, soda-lime glass has relatively high alkalis and that could accelerate the ASR.

As glass contains both of the deterioration factors for inducing ASR in concrete (i.e., reactive silica and alkalis), concrete prepared with GA is more susceptible to ASR distress than conventional concrete prepared with NA [72]. The fineness of glass can potentially alter the rate of silica dissolution on the surface of GA in a high alkali pore solution. The main problem with ASR is the use of GA replacement that occurs between the GA and the alkalis produced by the cement during hydration [71,73]. Amorphous silica in glass is susceptible to attack by the alkaline environment and would depolymerize to form a monomer Si(OH)₄, which could further react with alkalis such as Na⁺, K⁺ and Ca²⁺ to form the ASR gel [74]. When ASR gel absorbs water, it starts to swell and exert pressure inside concrete causing cracks. Swelling ASR gel would occur inside inherent micro-cracks of glass particles, rather than at surface. Therefore, inherent micro-cracks in larger glass particles would render more reaction and higher expansion [25]. Using high content GA in concrete results in a lower durability of concrete because ASR not only leads to micro-cracks and damage in cement matrix, but also inside GA, especially for the large glass particles [70].

4.3. Effect of Recycled Glass on Durability Properties of Concrete

4.3.1. Effect of Recycled Glass on Transport Properties of Concrete

Table 3 shows the effect of RG on transport properties of concrete. GP as a partial cement replacement in the concrete resulted in the improvement of the transport properties among the most previous studies. The optimum value of GP as partial cement replacement is 15–20%. This is explained by two mechanisms as follows: the filling and packing effect to GP and the pozzolanic reaction of GP and how it consumes part of the calcium hydroxides forming secondary C-S-H by which fills the capillary pores during the hydration of cement. Nevertheless, carbonation in not significantly improved as reviewed by [67,75]. The reason is low gel decalcification and high dosage of alkalis of glass [70].

On the other hand, the transport property affects GA, specifically WA, WP, and porosity of concrete by affecting the voids existing in concrete. The irregular angular shape of the glass particles is responsible for the increased water demand compared to PC mixes [54]. Its influence on glass of concrete is considered a complex process specifically GA, and has interconnection between GA particles and between GA and NA. GA has smooth surface that contributes in preventing internal friction, possibility of compressibility, and low voids. However, this means reduction in adhesion improvement with binder material. GA affects the microstructure of the interfacial transition zone (ITZ) as a result of poor bonding between the GA and cement paste at the ITZ due to the smooth surface of the GA [76]. Consequently, low W/C concrete is suitable when there is GA in the mix. The behavior and rate of water transport vary according to the replacement ratio, glass volume, and glass type. Due to the smooth surface and negligible WA of GA, the adhesive bond between the materials within the fresh concrete reduces as the amount of GA increases. The increased friction between GA can result in low viscosity of the paste and easily flow out of the aggregate. Therefore, instability, segregation and excessive bleeding may be observed in concrete specifically concrete with high volumes of GA. Figure 6 depicts the scheme of reasonable assumption of water transport mechanism of NA and GA. It is noticed that hydrated cement could not be absorbed through GA easily such as NA; however, cement binding aggregates together is called effective binder.

FGA has a positive effect of transport property. It is noticed that all reviewed studies reported an improvement of the transport properties except [77]. W/C plays a critical role on water transport owing to the poor WA of glass compared with NA and this coincides with [78]. This may lead to an increase in the porosity of concrete surface layer, and cause a faster diffusion rate at the early stage of CP. Moreover, WP resistance of the concrete increased as the FGA substitution ratio increased, because of the low WA ratio of the glass.

Regarding GF, most of the previous studies have shown a good effect through adding a comparable value of 1.5% as volume fraction on transport property. This is ascribed to that most of the voids/pores are interlocked creating dense material by GF. This was explained by [79] that GF in concrete fills the voids and that reduces the permeability and prevents the development of shrinkage crack of concrete. GF could improve the bleeding of water and reduction in the permeability [80] and can similarly advance the properties to reactive powder concrete [81]. However, [63,82] showed a very little increment of WA and penetration depth, and this may ascribe to the extra length of GF which is 12 mm in comparison to other studies. In contrast, large quantity of GF may be harmful to the water transport.

Table 3. Effect of recycled glass on transport properties of concrete.

Glass Form	Type of Concrete	Transport Property	Replacement/ Addition Ratio	W/C	Findings	Ref.
GP	Normal	WA,WP	5%, 10%, 15%, 20% & 35%	0.438	WA and WP were improved up to 15% of GP.	[83]
	Normal	WA	10%, 20% & 30%	0.42	Increase of WA was observed with incorporation of GP in comparison to reference concrete.	[84]
	SCC	Oxygen permeability, water porosity, sorptivity, chloride diffusion, carbonation	20% & 40%	0.32 & 0.27	GP lowered sorptivity due to the refinement of pore structure of concrete. It reduced the gas permeability coefficient and exhibited higher CP resistance. On contrary, it did not show performance against carbonation.	[75]
	Normal	WA	22.5% & 45%	0.55 & 0.65	GP does not increase WA of concrete.	[69]
	Normal	WA, RCPT	5%, 10%, 15% & 20%	0.50	Replacement of cement with GP showed lower WA and lower coulomb values, which signifies that the concrete was less porous and denser. The optimum ratio of GP was 20%	[85]
	Normal	Carbonation	10% & 20%	0.40	There was no positive influence on the carbonation resistance.	[67]
	Normal	WA	10% & 20%	0.42	GP rubberized concrete showed the least WA rate than all other batches.	[86]
	Normal	Oxygen permeability, chloride diffusion-electrical resistivity, water porosity	20%, 30% & 40%	0.40	GP exhibited lower oxygen permeability and chloride diffusion coefficient along with high electrical resistivity confirming a refinement of pore structure. The optimum ratio of GP replacement was 20–30%.	[54]
	Normal	WA, WP, RCPT	5%, 10%, 15%, 20% & 25%	0.53	WA and WP of mixes were reduced with an increase up to 15% of GP. The reason was a reduction in porosity and voids due to filler effect.	[87]
	Normal	RCPT, CP, chloride diffusion, electrical resistivity	10% & 20%	0.60	The use of GP improved CP resistance in chloride diffusion test. Electrical resistivity confirmed the gains of resistance against CP of the concretes with GP.	[56]
	HPC	RCPT	10%	0.50	The RCPT of GP in concrete was in the low and the very low range at 28 and 91 days respectively.	[41]
	Normal	Water porosity, RCPT, CP, chloride diffusion	20%	0.35	The different chlorides tests confirm the durability improvement of GP due to micro filler effect and reactivity.	[68]
	SCC	WA	5–30%	0.51	The results showed that up to 20% GP replacement, the WA is less or could be compared with the control mix.	[88]
	Normal	RCPT	10%, 20% & 30%	0.42–0.50	GP reduces CP of concrete to approximately one-third. The optimum ratio of GP was 20%.	[89]
	Normal	RCPT, WP sorptivity, water porosity	15%, 30%, 45% & 60%	0.487	All mixes containing GP exhibited much better resistance to water transport and chloride ions, attributed to the refined pore system. The optimum ratios were 15% and 30%.	[90]
	Normal	WA, WP chloride diffusion, sorptivity	15%, 30%, 45% & 60%	0.487	Concrete exhibited a higher resistance to WA, WP and chloride diffusivity, with cement partially substituted by GP. The reason is due to the refined microstructure of paste and pozzolanic reaction. The optimum ratio was 30%.	[91]
	Normal	Water porosity, RCPT, CP chloride diffusion, electrical resistivity	5%, 10%, 15% & 20%	0.50	Concrete modified with GP was found to exhibit improved resistance to CP and electrical resistivity. Porosity did not show noticeable changes. The optimum ratio was 20%	[57]
	Normal	RCPT, oxygen permeability	30%	0.30	CP is very low on concrete with GP. The diffusion of chloride ions decreases significantly because of the effect of denser microstructure. The oxygen permeability of mixes with GP was improved.	[11]
	Normal	RCPT,WP	15%, 30%, 45% & 60%	0.487	Resistance to chloride ion and WP resistance were greatly improved by replacing cement with GP, due to the refined microstructure of paste and pozzolanic reaction. The optimum ratio was 15%	[49]
	Normal	Chloride diffusion	5% & 10%	0.45	All mixture containing GP have lower values of chloride diffusion coefficient than control sample, thus improved the resistance of concrete to CP.	[51]
	Normal	WA,RCPT sorptivity	20%	0.38 & 0.50	The use GP in recycled aggregate concrete results in enhanced WA, sorptivity, and CP.	[8]
GA	UHPC	Carbonation, Chloride diffusion	25% (FGA)	0.21	A very low carbonation coefficient of 0.5 mm/year−1 was obtained allowed the concrete cover to be reduced. The chloride diffusion coefficient was low allowed structures to come into contact with salt water.	[53]
	Normal	Oxygen permeability, sorptivity	15% & 30% (FGA)	0.50	The inclusion of FGA in concrete resulted in a concrete with low permeability against oxygen and sorptivity.	[92]
	SCC	Electrical resistivity	15% & 25% (FGA)	0.47	The electrical resistivity values of all the mixtures containing FGA remained close to 5 kΩ-cm on day 7 and then steeply increased with age.	[58]
	Normal	WA	5%, 10%, 15% & 20% (FGA&CGA)	0.42	The combination of FGA and CGA is effective in the reduction of WA. The optimum ratio was 10%.	[35]
	Normal	RCPT	10%, 20%, 30%, 40% & 50% (FGA)	0.50, 0.45, 0.40, 0.35 & 0.30	The RCPT test results show that chloride ion penetration rate was highly reduced with addition of FGA and permeability of concrete is enhanced up to 50% replacement levels without affecting the strength.	[9]
	Normal	WA, CP, Chloride diffusion	0–100% (FGA)	0.35, 0.40 & 0.45	WA, CP and diffusion coefficient decreased as FGA ratio increased in all of the mixing conditions. This lead to an increase of the permeability resistance of the concrete.	[39]
	Normal	WA, WP, sorptivity	18–24% (FGA)	0.40	Increase in WA, WP and sorptivity of FGA concrete has been observed when compared with control concrete due to generation of permeable pores.	[77]
	Normal	WA, WP sorptivity, RCPT	15%, 30%, 45% & 60% (FGA)	0.45	WA, WP and sorptivity of the concrete mixture was improved slightly with increasing GA content.	[93]
	Normal	RCPT, electrical resistance	20%, 40%, 60% & 80% (FGA)	0.485	The penetration level of the chloride ion for specimens with glass sand replacement, was less than that of the control group. The electrical resistances of the concretes were less than 20 kΩ cm and larger than that of the control group for the mixes when measured at 90 days. It is increasing with increased amounts of glass sand replacement.	[94]
	Normal	WA, CP, sorptivity, carbonation	5%, 10% & 20 (FGA&CGA)	0.55, 0.57 & 0.58	WA by immersion of simultaneous incorporation of FGA and CGA was similar to the reference concrete and is better in terms of WA by capillarity, as do the mixes with either CGA or FGA for replacement amounts up to 10%. There was an improvement in carbonation resistance in the long-term. CP with any size and combination of FGA and CGA proved to be slightly lower than the reference concrete.	[50]
GF	HPC	Sorptivity	0.5% & 1% vol. fraction	0.25	The sorptivity index values less than 0.06 mm/min1/2 were achieved for all mixtures.	[95]
	Normal	WA, RCPT Sorptivity, water porosity, chloride diffusion	1% vol. fraction	0.45	WA and sorptivity of the mix were found to be reduced with the addition of GF. CP depth and bulk diffusion coefficient of GF reinforced concrete mixes were less than that of conventional concrete mixes.	[96]
	Normal	WA, CP	1%, 1.5%, 2%, 2.5% & 3% cement wt.	0.45	WA decreased with GF addition. Chloride ions passage is reduced with addition of GF because Most of the voids/pores of concrete were interlocked by GF. 2% of cement weight was the optimum ratio.	[97]
	Normal	WP, Sorptivity	1.5% wt. fraction	0.50	GF proved the effectiveness of the sorptivity and WP at high temperatures.	[98]
	Normal	WA, CP	0.5% vol. fraction	0.40	WA and CP increased with the incorporation of GF into concrete due to increase in connectivity of pore volume.	[45]
	Normal	WA, CP	0.5% vol. fraction	0.50	GF showed slightly higher WA and CP compared to control concrete.	[63]
	Normal	WA, CP	0.50% vol. fraction	0.40	GF showed slightly higher WA and CP compared to control concrete.	[82]
	Shotcrete	WA	0.5%, 0.7%, & 1% vol. fraction	0.50	WA was reduced which will make it an appropriate protective layer where there might be water dripping problems.	[99]
	Normal	RCPT, CP chloride diffusion	0.5%, 1% & 1.5% vol. fraction	0.42	Adding the fiber material in concrete could significantly reduce the chloride migration depth and coefficient of the fiber reinforced concrete.	[79]
	HSC	WA, RCPT sorptivity	0.5%, 1%, 1.5% & 2% vol. fraction	0.54	GF absorbed less water when compared to the other mix proportions. Sorptivity showed that it had low number of pores. GF had higher resistance to CP. 1.5% volume fraction is optimum ratio in comparison to other mixes.	[100]

Table 3. Effect of recycled glass on transport properties of concrete.

Glass Form	Type of Concrete	Transport Property	Replacement/ Addition Ratio	W/C	Findings	Ref.
GP	Normal	WA,WP	5%, 10%, 15%, 20% & 35%	0.438	WA and WP were improved up to 15% of GP.	[83]
	Normal	WA	10%, 20% & 30%	0.42	Increase of WA was observed with incorporation of GP in comparison to reference concrete.	[84]
	SCC	Oxygen permeability, water porosity, sorptivity, chloride diffusion, carbonation	20% & 40%	0.32 & 0.27	GP lowered sorptivity due to the refinement of pore structure of concrete. It reduced the gas permeability coefficient and exhibited higher CP resistance. On contrary, it did not show performance against carbonation.	[75]
	Normal	WA	22.5% & 45%	0.55 & 0.65	GP does not increase WA of concrete.	[69]
	Normal	WA, RCPT	5%, 10%, 15% & 20%	0.50	Replacement of cement with GP showed lower WA and lower coulomb values, which signifies that the concrete was less porous and denser. The optimum ratio of GP was 20%	[85]
	Normal	Carbonation	10% & 20%	0.40	There was no positive influence on the carbonation resistance.	[67]
	Normal	WA	10% & 20%	0.42	GP rubberized concrete showed the least WA rate than all other batches.	[86]
	Normal	Oxygen permeability, chloride diffusion-electrical resistivity, water porosity	20%, 30% & 40%	0.40	GP exhibited lower oxygen permeability and chloride diffusion coefficient along with high electrical resistivity confirming a refinement of pore structure. The optimum ratio of GP replacement was 20–30%.	[54]
	Normal	WA, WP, RCPT	5%, 10%, 15%, 20% & 25%	0.53	WA and WP of mixes were reduced with an increase up to 15% of GP. The reason was a reduction in porosity and voids due to filler effect.	[87]
	Normal	RCPT, CP, chloride diffusion, electrical resistivity	10% & 20%	0.60	The use of GP improved CP resistance in chloride diffusion test. Electrical resistivity confirmed the gains of resistance against CP of the concretes with GP.	[56]
	HPC	RCPT	10%	0.50	The RCPT of GP in concrete was in the low and the very low range at 28 and 91 days respectively.	[41]
	Normal	Water porosity, RCPT, CP, chloride diffusion	20%	0.35	The different chlorides tests confirm the durability improvement of GP due to micro filler effect and reactivity.	[68]
	SCC	WA	5–30%	0.51	The results showed that up to 20% GP replacement, the WA is less or could be compared with the control mix.	[88]
	Normal	RCPT	10%, 20% & 30%	0.42–0.50	GP reduces CP of concrete to approximately one-third. The optimum ratio of GP was 20%.	[89]
	Normal	RCPT, WP sorptivity, water porosity	15%, 30%, 45% & 60%	0.487	All mixes containing GP exhibited much better resistance to water transport and chloride ions, attributed to the refined pore system. The optimum ratios were 15% and 30%.	[90]
	Normal	WA, WP chloride diffusion, sorptivity	15%, 30%, 45% & 60%	0.487	Concrete exhibited a higher resistance to WA, WP and chloride diffusivity, with cement partially substituted by GP. The reason is due to the refined microstructure of paste and pozzolanic reaction. The optimum ratio was 30%.	[91]
	Normal	Water porosity, RCPT, CP chloride diffusion, electrical resistivity	5%, 10%, 15% & 20%	0.50	Concrete modified with GP was found to exhibit improved resistance to CP and electrical resistivity. Porosity did not show noticeable changes. The optimum ratio was 20%	[57]
	Normal	RCPT, oxygen permeability	30%	0.30	CP is very low on concrete with GP. The diffusion of chloride ions decreases significantly because of the effect of denser microstructure. The oxygen permeability of mixes with GP was improved.	[11]
	Normal	RCPT,WP	15%, 30%, 45% & 60%	0.487	Resistance to chloride ion and WP resistance were greatly improved by replacing cement with GP, due to the refined microstructure of paste and pozzolanic reaction. The optimum ratio was 15%	[49]
	Normal	Chloride diffusion	5% & 10%	0.45	All mixture containing GP have lower values of chloride diffusion coefficient than control sample, thus improved the resistance of concrete to CP.	[51]
	Normal	WA,RCPT sorptivity	20%	0.38 & 0.50	The use GP in recycled aggregate concrete results in enhanced WA, sorptivity, and CP.	[8]
GA	UHPC	Carbonation, Chloride diffusion	25% (FGA)	0.21	A very low carbonation coefficient of 0.5 mm/year−1 was obtained allowed the concrete cover to be reduced. The chloride diffusion coefficient was low allowed structures to come into contact with salt water.	[53]
	Normal	Oxygen permeability, sorptivity	15% & 30% (FGA)	0.50	The inclusion of FGA in concrete resulted in a concrete with low permeability against oxygen and sorptivity.	[92]
	SCC	Electrical resistivity	15% & 25% (FGA)	0.47	The electrical resistivity values of all the mixtures containing FGA remained close to 5 kΩ-cm on day 7 and then steeply increased with age.	[58]
	Normal	WA	5%, 10%, 15% & 20% (FGA&CGA)	0.42	The combination of FGA and CGA is effective in the reduction of WA. The optimum ratio was 10%.	[35]
	Normal	RCPT	10%, 20%, 30%, 40% & 50% (FGA)	0.50, 0.45, 0.40, 0.35 & 0.30	The RCPT test results show that chloride ion penetration rate was highly reduced with addition of FGA and permeability of concrete is enhanced up to 50% replacement levels without affecting the strength.	[9]
	Normal	WA, CP, Chloride diffusion	0–100% (FGA)	0.35, 0.40 & 0.45	WA, CP and diffusion coefficient decreased as FGA ratio increased in all of the mixing conditions. This lead to an increase of the permeability resistance of the concrete.	[39]
	Normal	WA, WP, sorptivity	18–24% (FGA)	0.40	Increase in WA, WP and sorptivity of FGA concrete has been observed when compared with control concrete due to generation of permeable pores.	[77]
	Normal	WA, WP sorptivity, RCPT	15%, 30%, 45% & 60% (FGA)	0.45	WA, WP and sorptivity of the concrete mixture was improved slightly with increasing GA content.	[93]
	Normal	RCPT, electrical resistance	20%, 40%, 60% & 80% (FGA)	0.485	The penetration level of the chloride ion for specimens with glass sand replacement, was less than that of the control group. The electrical resistances of the concretes were less than 20 kΩ cm and larger than that of the control group for the mixes when measured at 90 days. It is increasing with increased amounts of glass sand replacement.	[94]
	Normal	WA, CP, sorptivity, carbonation	5%, 10% & 20 (FGA&CGA)	0.55, 0.57 & 0.58	WA by immersion of simultaneous incorporation of FGA and CGA was similar to the reference concrete and is better in terms of WA by capillarity, as do the mixes with either CGA or FGA for replacement amounts up to 10%. There was an improvement in carbonation resistance in the long-term. CP with any size and combination of FGA and CGA proved to be slightly lower than the reference concrete.	[50]
GF	HPC	Sorptivity	0.5% & 1% vol. fraction	0.25	The sorptivity index values less than 0.06 mm/min1/2 were achieved for all mixtures.	[95]
	Normal	WA, RCPT Sorptivity, water porosity, chloride diffusion	1% vol. fraction	0.45	WA and sorptivity of the mix were found to be reduced with the addition of GF. CP depth and bulk diffusion coefficient of GF reinforced concrete mixes were less than that of conventional concrete mixes.	[96]
	Normal	WA, CP	1%, 1.5%, 2%, 2.5% & 3% cement wt.	0.45	WA decreased with GF addition. Chloride ions passage is reduced with addition of GF because Most of the voids/pores of concrete were interlocked by GF. 2% of cement weight was the optimum ratio.	[97]
	Normal	WP, Sorptivity	1.5% wt. fraction	0.50	GF proved the effectiveness of the sorptivity and WP at high temperatures.	[98]
	Normal	WA, CP	0.5% vol. fraction	0.40	WA and CP increased with the incorporation of GF into concrete due to increase in connectivity of pore volume.	[45]
	Normal	WA, CP	0.5% vol. fraction	0.50	GF showed slightly higher WA and CP compared to control concrete.	[63]
	Normal	WA, CP	0.50% vol. fraction	0.40	GF showed slightly higher WA and CP compared to control concrete.	[82]
	Shotcrete	WA	0.5%, 0.7%, & 1% vol. fraction	0.50	WA was reduced which will make it an appropriate protective layer where there might be water dripping problems.	[99]
	Normal	RCPT, CP chloride diffusion	0.5%, 1% & 1.5% vol. fraction	0.42	Adding the fiber material in concrete could significantly reduce the chloride migration depth and coefficient of the fiber reinforced concrete.	[79]
	HSC	WA, RCPT sorptivity	0.5%, 1%, 1.5% & 2% vol. fraction	0.54	GF absorbed less water when compared to the other mix proportions. Sorptivity showed that it had low number of pores. GF had higher resistance to CP. 1.5% volume fraction is optimum ratio in comparison to other mixes.	[100]

4.3.2. Effect of Recycled Glass on Chemical Attack of Concrete

Table 4 shows the effect of RG on chemical attack of concrete. The chemical resistance of GP as partial cement replacement of the concrete results in the improvement of sulfate and acid attacks among the most previous studies. The optimum value of GP as partial cement replacement is 10–20%. This is explained that GP incorporation reduces the calcium oxide content of binder and leads to low production of calcium hydroxide compared to control mix. The pozzolanic reaction of GP consumes part of the calcium hydroxide and clings to aggregate surface forming secondary C-S-H which enhances the density of cement paste around the aggregate [84]. This fills the capillary pores during the hydration of cement. Moreover, the replacement of a portion of cement with GP reduces the total amount of tri-calcium aluminate hydrate in the concrete, which is responsible for the formation of ettringite. Thus, the quantity of expansive gypsum formed by the reaction of calcium hydroxide will be less in concrete [61].

The chemical resistance of GA was reviewed by three previous studies. Ref. [35] tested the sulfuric acid attack by adding FGA and CGA together according to the distribution of glass particles (0.15–12.5 mm) with different ratios, while Refs. [39,53] tested sulfate attack by replacing aggregates with FGA. It is noticed from the aforementioned studies that there is an improvement in chemical resistance. The chemical resistance improvement of concrete specimens comprising FGA and CGA may be related to higher resistance of glass particles against sulfate and sulfuric acid attack, and the lower WA of glass improves the chemical resistance of concrete [35]. GA reduces the disintegration of concrete constituents. Hence, it retains the weight and compressive strength of concrete specimens at higher substitution percentages [65].

Adding GF to concrete was enhanced against chemical attack as emphasized by all reviewed studies when using up to 1.5% volume fraction of cement.

Table 4. Effect of recycled glass on chemical attack of concrete.

Glass Form	Type of Concrete	Chemical Property	Replacement/ Addition Ratio	W/C	Findings	Ref.
GP	Normal	Sulfate attack	5%, 10%, 15, 20% & 35%	0.438	Concrete composition with replacement of cement with GP up to 15% meets the requirements for practical use of concrete which is exposed to aggressive environment.	[83]
	Normal	Sulfate attack	10% & 20%	0.40	GP proved to be very effective in improving the resistance to sulfate resistance of modified concretes up to 20% replacement.	[67]
	Normal	Sulfuric acid attack	10%, 20% & 30%	0.42	Acid resistance increased with incorporation of GP up to 20% substitution. It is due to formation C-S-H which enhances the density of cement paste around the aggregate.	[84]
	Normal	Hydrochloride acid attack, magnesium sulfate attack	5%, 10%, 15% & 20%	0.50	Replacement up to 15% of GP slightly improved the reduced strength of plastic admixed specimen immersed in 5% HCl for 90 days. Replacement up to 20% of GP slightly improved the reduced strength of plastic admixed specimen immersed in 5% MgSO4 for 90 days.	[85]
	Normal	Sulfate attack	30%	0.43	The incorporation of recycled fine aggregate accompanied GP leads to significant improvements in the development of concrete compressive strength in sulfate environment. This is ascribed to interaction of GP with the adhered mortar on the surface of recycled aggregate to form C-S-H	[101]
	Normal	Acid attack, sulfate attack	5%, 10%, 15%, 20% & 25%	0.53	Behavior of blended concrete mixes in acid and sulfate attack was better than control concrete in terms of the loss in compressive strength in sulfuric acid and sodium sulfate solutions. This is due to the packing of concrete by a finer particle of GP. The optimum ratio was 15%.	[87]
	Normal	Sulfate attack, chloride attack	5%, 10%, 15%, 20%, 25%, 30%, 35% & 40%	0.45	Concrete supplanting 20% of the cement by GP indicated more strength by 3–23% when cement exposed to chloride attack and 6–27% when cement exposed to sulfate attack. Chloride attack brought down the compressive strength ranges between 3% and 19%. Sulfate attack brought down the compressive strength ranges somewhere in the range of 2% and 17%.	[13]
	Normal	Sulfate attack	10%, 20% & 30%	0.54, 0.41	Replacing cement by GP up to 30% has a positive effect on the durability of concrete exposed to sodium sulfate solution. The W/C ratio is an important factor in controlling the damage of concrete subjected to sulfate attack.	[61]
	-Normal -SCC	Hydrochloride acid attack	6%, 13% & 20%	0.376	Better durability in the acidic medium can be obtained by minimizing the usage of GP and superplasticizer.	[102]
	-SCC -Normal	Sulfuric acid	6%, 13% & 20%	0.376	Based on artificial neural networks analysis, higher GP contents and even concretes with low compressive strength enhance the performance in an H2SO4 acid medium. Therefore, higher compressive strengths do not necessarily ensure improved durability.	[103]
	HPC	Sulfate attack	10%	0.50	The pozzolanic reaction of GP contributes to control expansions of sulfate attack.	[41]
	Normal	Sulfates attack	30%	0.30	From X-ray diffraction analyses, it is observed that GP helps reduce the amount of portlandite in cement pastes due to the pozzolanic effect.	[11]
GA	UHPC	Sulfuric acid	25% (FGA)	0.21	FGA in concrete showed very good resistance to acid attack at pH 3.5.	[53]
	SCC	Sulfuric acid attack	5%, 10%, 15% & 20% (FGA&CGA)	0.42	The resistance of mixtures against sulfuric acid attack was enhanced by increasing of GA and peak at 20% substitution. According to the results of mass loss, the maximum improvement for the mixtures was 52.23% when compared to the control mixture.	[35]
	Normal	Sulfate attack	0–100% (FGA)	0.35, 0.40 & 0.45	FGA in concrete may have improved the sulfate attack resistance of the concrete.	[39]
GF	HPC	Sulfuric acid attack	0.5% & 1% vol. fraction	0.25	Mixtures lost more than 25% of their mass after the 2-month sulfuric acid attack. About an average 9% reduction in their dimensions was observed.	[95]
	Normal	Acid attack	1% vol. fraction	0.45	GF exhibited better chemical resistance compared to conventional concrete. It may be due to GF increases concrete toughness and density.	[96]
	Normal	Acid attack	0.5% vol. fraction	0.50	Acid attack resistance of GF in concrete was more than the corresponding PC mix.	[63]
	Normal	Acid attack	0.5% vol. fraction	0.40	Despite the increased permeability, GF was more useful to acid resistance of concrete.	[82]
	Normal	Sulfuric acid, hydrochloric acid	0.1%, 0.15%, 0.2% & 0.25% cement wt.	0.45	The durability of designed pervious concrete was found to be satisfactory when the mixes were tested against acids. Hence there is no much degradation of fibers was found.	[104]
	HSC	Sulfate attack, acid attack	0.5%, 1%, 1.5% & 2% vol. fraction	0.54	In the sulfate attack test, the compressive strength loss of the 1.5% GF specimen ranged from 9.91% to 12.6%. The compressive strength loss for the specimen exposed to 1% sulfuric acid was 17.49% to 22.8%. The recommended ratio of GF was 1.5%.	[100]

Table 4. Effect of recycled glass on chemical attack of concrete.

Glass Form	Type of Concrete	Chemical Property	Replacement/ Addition Ratio	W/C	Findings	Ref.
GP	Normal	Sulfate attack	5%, 10%, 15, 20% & 35%	0.438	Concrete composition with replacement of cement with GP up to 15% meets the requirements for practical use of concrete which is exposed to aggressive environment.	[83]
	Normal	Sulfate attack	10% & 20%	0.40	GP proved to be very effective in improving the resistance to sulfate resistance of modified concretes up to 20% replacement.	[67]
	Normal	Sulfuric acid attack	10%, 20% & 30%	0.42	Acid resistance increased with incorporation of GP up to 20% substitution. It is due to formation C-S-H which enhances the density of cement paste around the aggregate.	[84]
	Normal	Hydrochloride acid attack, magnesium sulfate attack	5%, 10%, 15% & 20%	0.50	Replacement up to 15% of GP slightly improved the reduced strength of plastic admixed specimen immersed in 5% HCl for 90 days. Replacement up to 20% of GP slightly improved the reduced strength of plastic admixed specimen immersed in 5% MgSO4 for 90 days.	[85]
	Normal	Sulfate attack	30%	0.43	The incorporation of recycled fine aggregate accompanied GP leads to significant improvements in the development of concrete compressive strength in sulfate environment. This is ascribed to interaction of GP with the adhered mortar on the surface of recycled aggregate to form C-S-H	[101]
	Normal	Acid attack, sulfate attack	5%, 10%, 15%, 20% & 25%	0.53	Behavior of blended concrete mixes in acid and sulfate attack was better than control concrete in terms of the loss in compressive strength in sulfuric acid and sodium sulfate solutions. This is due to the packing of concrete by a finer particle of GP. The optimum ratio was 15%.	[87]
	Normal	Sulfate attack, chloride attack	5%, 10%, 15%, 20%, 25%, 30%, 35% & 40%	0.45	Concrete supplanting 20% of the cement by GP indicated more strength by 3–23% when cement exposed to chloride attack and 6–27% when cement exposed to sulfate attack. Chloride attack brought down the compressive strength ranges between 3% and 19%. Sulfate attack brought down the compressive strength ranges somewhere in the range of 2% and 17%.	[13]
	Normal	Sulfate attack	10%, 20% & 30%	0.54, 0.41	Replacing cement by GP up to 30% has a positive effect on the durability of concrete exposed to sodium sulfate solution. The W/C ratio is an important factor in controlling the damage of concrete subjected to sulfate attack.	[61]
	-Normal -SCC	Hydrochloride acid attack	6%, 13% & 20%	0.376	Better durability in the acidic medium can be obtained by minimizing the usage of GP and superplasticizer.	[102]
	-SCC -Normal	Sulfuric acid	6%, 13% & 20%	0.376	Based on artificial neural networks analysis, higher GP contents and even concretes with low compressive strength enhance the performance in an H2SO4 acid medium. Therefore, higher compressive strengths do not necessarily ensure improved durability.	[103]
	HPC	Sulfate attack	10%	0.50	The pozzolanic reaction of GP contributes to control expansions of sulfate attack.	[41]
	Normal	Sulfates attack	30%	0.30	From X-ray diffraction analyses, it is observed that GP helps reduce the amount of portlandite in cement pastes due to the pozzolanic effect.	[11]
GA	UHPC	Sulfuric acid	25% (FGA)	0.21	FGA in concrete showed very good resistance to acid attack at pH 3.5.	[53]
	SCC	Sulfuric acid attack	5%, 10%, 15% & 20% (FGA&CGA)	0.42	The resistance of mixtures against sulfuric acid attack was enhanced by increasing of GA and peak at 20% substitution. According to the results of mass loss, the maximum improvement for the mixtures was 52.23% when compared to the control mixture.	[35]
	Normal	Sulfate attack	0–100% (FGA)	0.35, 0.40 & 0.45	FGA in concrete may have improved the sulfate attack resistance of the concrete.	[39]
GF	HPC	Sulfuric acid attack	0.5% & 1% vol. fraction	0.25	Mixtures lost more than 25% of their mass after the 2-month sulfuric acid attack. About an average 9% reduction in their dimensions was observed.	[95]
	Normal	Acid attack	1% vol. fraction	0.45	GF exhibited better chemical resistance compared to conventional concrete. It may be due to GF increases concrete toughness and density.	[96]
	Normal	Acid attack	0.5% vol. fraction	0.50	Acid attack resistance of GF in concrete was more than the corresponding PC mix.	[63]
	Normal	Acid attack	0.5% vol. fraction	0.40	Despite the increased permeability, GF was more useful to acid resistance of concrete.	[82]
	Normal	Sulfuric acid, hydrochloric acid	0.1%, 0.15%, 0.2% & 0.25% cement wt.	0.45	The durability of designed pervious concrete was found to be satisfactory when the mixes were tested against acids. Hence there is no much degradation of fibers was found.	[104]
	HSC	Sulfate attack, acid attack	0.5%, 1%, 1.5% & 2% vol. fraction	0.54	In the sulfate attack test, the compressive strength loss of the 1.5% GF specimen ranged from 9.91% to 12.6%. The compressive strength loss for the specimen exposed to 1% sulfuric acid was 17.49% to 22.8%. The recommended ratio of GF was 1.5%.	[100]

4.3.3. Effect of Recycled Glass on Freeze-Thaw of Concrete

Table 5 shows the effect of RG on FT of concrete. All reviewed studies have indicated the good effectiveness of GP in resisting FT. Refs. [36,69], satisfied FT the resistance criteria defined for concrete Polish standard no. PN-S-96014:1997 and PN-B 06250:1988 respectively. Ref. [68] reported high durability factor for GP sample based on entrained air and strength of cement matrix rather than the packing effect and contribution of pozzolanic reaction. Moreover, refs. [51,89] reported that the durability factors of the RDME were 60% higher than that specified in ASTM C666. The optimum ratio for incorporation of GP is 15–20%. Therefore, GP is favorable for FT resistance because it serves as a nucleation for air bubbles due to its angularity and finer particle size than ordinary concrete.

Two reviewed studies have been addressed to test GA in concrete. Ref. [39] tested FGA replacement with a ratio of 0–100% as fine aggregate replacement for different W/C ratios. The test results shows that concrete has no significant weight change before and after the FT and have good ratio of RDME in FT resistance indicating the concrete containing FGA has a good FT resistance. Due to low absorption capacity, GA is potentially able to improve resistance to FT attack [105]. In addition, expanded GA is effective as light-weight aggregate for frost resistance [19].

Table 5. Effect of recycled glass on freeze-thaw of concrete.

Glass Form	Type of Concrete	Replacement/ Addition Ratio	W/C	Findings	Ref.
GP	Normal	5%, 10%, 15%, 20% & 35%	0.438	The concretes modified with 20% GP reached the ultimate values in terms of resistance to FT action and simultaneous action of freezing and defrosting salt.	[83]
	Normal	22.5% & 45%	0.55 & 0.65	Mixes with GP satisfied FT resistance criteria defined for concrete in the Polish standard no. PN-S-96014:1997	[69]
	Normal	20%, 30% & 40%	0.41	The effect of GP after several FT cycles was clearly noticeable. It satisfied the requirements of either the F25 or F100 class, as per PN-B 06250:1988.	[36]
	Normal	10% & 20%	0.40	GP proved to be very effective in improving the resistance to FT.	[67]
	Normal	10% & 20%	0.42	GP rubberized concrete mixes exhibited good FT performance.	[86]
	Roller compacted	10%, 15% & 20%	0.37	The compacted concrete containing an air-entraining agent was not susceptible to frost damage.GP mixture was ruptured after a larger number of FT cycles 267 compared to that of the reference mixture.	[106]
	Normal	20%	0.35	The highest durability factor is presented when GP is mixed. This is because FT resistance is determined by entrained air and strength of cement matrix rather than the packing effect and contribution of pozzolanic reaction.	[68]
	Normal	10%, 20% & 30%	0.42–0.50	After 300 FT cycles, durability factors of the RDME were 60% higher than that specified in ASTM C666 to ensure good durability. No deterioration or cracking was observed in any of the specimens.	[89]
	Normal	10%	0.45	The results showed that the RDME of all mixtures with glass sludge in both conditions, water and salt solution, are higher than that of the control mixture. The RDME of the glass sludge samples did not fall below 80% after 300 cycles.	[51]
	Normal	6–18%	0.40 & 0.60	The performance of GP concrete to FT cycling was observed higher compared to that of plain concrete. It increased with increasing the GP replacement level. The influence of W/C ratio on the performance of concrete to FT damage is more effective for GP concrete than for plain concrete.	[66]
	Normal	20%	0.38 & 0.50	The use GP in recycled aggregate concrete results in enhanced FT.	[8]
GA	UHPC	25% (FGA)	0.21	In frost tests, the high impermeability of the concrete containing FGA ensured very good properties. Little weathering (68 g/m2) was measured.	[53]
	Normal	0–100% (FGA)	0.35, 0.40, & 0.45	The FT resistance test showed that the weight of the concrete did not significantly change due to FT. The ratio of the RDME was higher than 80% in all of the mixing conditions, indicating that concrete containing GA had good FT resistance.	[39]
GF	Normal	0.3%, 0.5%, 0.7% & 1% vol. fraction	0.49	GF can greatly improve the FT resistance.	[107]

Table 5. Effect of recycled glass on freeze-thaw of concrete.

Glass Form	Type of Concrete	Replacement/ Addition Ratio	W/C	Findings	Ref.
GP	Normal	5%, 10%, 15%, 20% & 35%	0.438	The concretes modified with 20% GP reached the ultimate values in terms of resistance to FT action and simultaneous action of freezing and defrosting salt.	[83]
	Normal	22.5% & 45%	0.55 & 0.65	Mixes with GP satisfied FT resistance criteria defined for concrete in the Polish standard no. PN-S-96014:1997	[69]
	Normal	20%, 30% & 40%	0.41	The effect of GP after several FT cycles was clearly noticeable. It satisfied the requirements of either the F25 or F100 class, as per PN-B 06250:1988.	[36]
	Normal	10% & 20%	0.40	GP proved to be very effective in improving the resistance to FT.	[67]
	Normal	10% & 20%	0.42	GP rubberized concrete mixes exhibited good FT performance.	[86]
	Roller compacted	10%, 15% & 20%	0.37	The compacted concrete containing an air-entraining agent was not susceptible to frost damage.GP mixture was ruptured after a larger number of FT cycles 267 compared to that of the reference mixture.	[106]
	Normal	20%	0.35	The highest durability factor is presented when GP is mixed. This is because FT resistance is determined by entrained air and strength of cement matrix rather than the packing effect and contribution of pozzolanic reaction.	[68]
	Normal	10%, 20% & 30%	0.42–0.50	After 300 FT cycles, durability factors of the RDME were 60% higher than that specified in ASTM C666 to ensure good durability. No deterioration or cracking was observed in any of the specimens.	[89]
	Normal	10%	0.45	The results showed that the RDME of all mixtures with glass sludge in both conditions, water and salt solution, are higher than that of the control mixture. The RDME of the glass sludge samples did not fall below 80% after 300 cycles.	[51]
	Normal	6–18%	0.40 & 0.60	The performance of GP concrete to FT cycling was observed higher compared to that of plain concrete. It increased with increasing the GP replacement level. The influence of W/C ratio on the performance of concrete to FT damage is more effective for GP concrete than for plain concrete.	[66]
	Normal	20%	0.38 & 0.50	The use GP in recycled aggregate concrete results in enhanced FT.	[8]
GA	UHPC	25% (FGA)	0.21	In frost tests, the high impermeability of the concrete containing FGA ensured very good properties. Little weathering (68 g/m2) was measured.	[53]
	Normal	0–100% (FGA)	0.35, 0.40, & 0.45	The FT resistance test showed that the weight of the concrete did not significantly change due to FT. The ratio of the RDME was higher than 80% in all of the mixing conditions, indicating that concrete containing GA had good FT resistance.	[39]
GF	Normal	0.3%, 0.5%, 0.7% & 1% vol. fraction	0.49	GF can greatly improve the FT resistance.	[107]

4.3.4. Effect of Recycled Glass on Alkali-Silica Reaction

Table 6 shows the effect of RG on ASR gel of concrete. It is very clear that the expansion of mortar bar decreases as the GP replacement level increases. One possible reason may be due to the high reactivity of GP with lime forming C-S-H gel in which the alkalis in the concrete partly was consumed in the C-S-H. GP dissipates a higher percentage of calcium (Ca²⁺) in both pozzolanic reaction and hydration products reducing SiO₂ to form the ASR gel, so the level of alkalis (Na/K) utilized in the ASR pore solution is reduced. [108]. The ratio 10–20% is appropriate to combat ASR in concrete. However, crystal glass exhibited the highest expansivity indicating ASR when cured in an alkali medium to simulate its behaviour in a PC mix due to its high content of elements that accelerate ASR (K, Na, Pb and Si) and its low content of glass stabilizers (CaO + MgO) [109].

Two previous studies highlighting the effect of GA in forming ASR were reviewed and concluded different results. Ref. [71] tested FGA with maximum size that did not exceed 1.25 mm in concrete with replacements 10%, 20%, 30%, and 50%. The analysis of the SEM-EDS images showed that no production of deleterious ASR. On contrary, ref. [58] tested FGA finer than 2.36 mm with replacements 40%, 60%, and 80%. SEM image showed that ASR expansion can be explained by analysis of size-effect behavior of glass and forms in interior cracks of the GA. In addition, the main concerns in the use of crushed glass as aggregates for PC concrete is the expansion and cracking caused by GA [94]. Large sizes of glass particles experience greater ASR deterioration in concrete [26]. This was explained by the schematic Figure 7 of the size effect on the ASR expansion. When the glass sizes are small, the pores in the concrete matrix are likely able to accommodate the expansive ASR gel [21].

Table 6. Effect of recycled glass on ASR gel of concrete.

Glass Form	Type of Concrete	Replacement/ Addition Ratio	W/C	Findings	Ref.
GP	Normal	10%, 20% & 30%	0.47	30% replacement with GP was the only mixtures to mitigate the ASR expansion of samples and keep it under the specified limit of the respective test methods. GP dissipates a higher percentage of calcium in both pozzolanic reaction and hydration products causing the insufficient presence of SiO2 to form the ASR gel.	[108]
	Normal	10% & 20%	0.60	Although the GP presented the alkali content above the normative limits, it was found that its use GP reduced the occurrence of ASR.	[56]
	HPC	10%	0.50	Glass fume of sample in ASR test expanded near to the level of the control sample due to the available alkali in the pore solution. At late age, the pozzolanic reaction of glass was triggered and expansion was stabilized.	[41]
	SCC	5–30%	0.51	The expansions in the ASR of GP are similar to those of the control mix and all can be considered innocuous. This indicates GP incur no more ASR risks than the cement in concrete.	[88]
	Normal	5%, 10%, 15% & 20%	0.50	GP is effective at replacement levels of 10% and 20% in suppressing ASR in cementitious materials.	[57]
	Normal	20%	0.38 & 0.50	The high surface area of GP changes the kinetics of chemical reaction towards pozzolanic reaction utilizing the available alkalis before production of a potential ASR gel.	[8]
GA	Normal	10%, 20%, 30% & 50% (FGA)	0.43	The analysis of the SEM-EDS pictures showed that the incorporation of FGA with maximum size 1.25 mm in concrete did not produce deleterious ASR and below the limit expansion value of 0.15%.	[71]
	SCC	15% & 25% (FGA)	0.47	The ASR test results and SEM analysis demonstrated that the larger particles of GA (2.36–1.18 mm) can result in higher ASR expansion because they contain wider and more accessible preexisting cracks for rapid progression of ASR.	[58]

Table 6. Effect of recycled glass on ASR gel of concrete.

Glass Form	Type of Concrete	Replacement/ Addition Ratio	W/C	Findings	Ref.
GP	Normal	10%, 20% & 30%	0.47	30% replacement with GP was the only mixtures to mitigate the ASR expansion of samples and keep it under the specified limit of the respective test methods. GP dissipates a higher percentage of calcium in both pozzolanic reaction and hydration products causing the insufficient presence of SiO2 to form the ASR gel.	[108]
	Normal	10% & 20%	0.60	Although the GP presented the alkali content above the normative limits, it was found that its use GP reduced the occurrence of ASR.	[56]
	HPC	10%	0.50	Glass fume of sample in ASR test expanded near to the level of the control sample due to the available alkali in the pore solution. At late age, the pozzolanic reaction of glass was triggered and expansion was stabilized.	[41]
	SCC	5–30%	0.51	The expansions in the ASR of GP are similar to those of the control mix and all can be considered innocuous. This indicates GP incur no more ASR risks than the cement in concrete.	[88]
	Normal	5%, 10%, 15% & 20%	0.50	GP is effective at replacement levels of 10% and 20% in suppressing ASR in cementitious materials.	[57]
	Normal	20%	0.38 & 0.50	The high surface area of GP changes the kinetics of chemical reaction towards pozzolanic reaction utilizing the available alkalis before production of a potential ASR gel.	[8]
GA	Normal	10%, 20%, 30% & 50% (FGA)	0.43	The analysis of the SEM-EDS pictures showed that the incorporation of FGA with maximum size 1.25 mm in concrete did not produce deleterious ASR and below the limit expansion value of 0.15%.	[71]
	SCC	15% & 25% (FGA)	0.47	The ASR test results and SEM analysis demonstrated that the larger particles of GA (2.36–1.18 mm) can result in higher ASR expansion because they contain wider and more accessible preexisting cracks for rapid progression of ASR.	[58]

4.4. Combined Effect of Recycled Glass and Pozzolanic Materials on Durability Properties

This section examines the combined effect of RG and pozzolanic materials on durability properties. Combining various forms of glass with pozzolanic materials in concrete enhances a synergistic effect so that concrete gain different properties related to the impact of pozzolanic activity and packing effect. The combination of different pozzolans in cementitious systems changes reaction processes, phase compositions and microstructure development as well as the behavior of the concrete [110]. Besides, adding pozzolanic to GA and GF helps overcome the limitations of RG and enhance the durability of concrete.

4.4.1. Combined Effect of Recycled Glass and Pozzolanic Materials on Transport Properties

Table 7. Combined effect of recycled glass and pozzolanic materials on transport properties.

Glass Form	Type of Concrete	Transport Property	Replacement/ Addition Ratio	W/C	Findings	Ref.
GP	UHPC	Sorptivity	1%, 2% & 3% GP 15% silica fume	0.19	The addition of nano GP significantly reduced WA under all curing regimes. The reduction rate was 48% for under internal curing.	[111]
	Normal	RCPT, CP, chloride diffusion, electrical resistivity	10% & 20% GP 10% & 20% metakaolin	0.60	The use of GP and metakaolin, in the combined form, improved CP and diffusion tests. Electrical resistivity confirmed the gains of resistance against CP.	[56]
	SCC	Electrical resistivity	15% & 25% GP 10% & 20% zeolite	0.47	Use of zeolite enhanced the electrical resistivity of mixtures, especially at 20% replacement levels of cement with zeolite.	[58]
	Normal	RCPT	10%, 20% & 30% GP 25% fly ash	0.45	Use of ground GF at all levels of cement replacement reduced chloride ion permeability values in concrete significantly.	[62]
	Normal	WA, sorptivity	5–45% GP 5–45% steel slag	0.50	For sorptivity test, the two ratios, (20% GP & 30% steel slag) and (15% GP & 35% steel slag) were found to absorb less water than the control mix by 37.3% and 17.7% respectively. For WA test, the same two ratios were found to absorb less water than the control mix by 15.15% and 6.1% respectively.	[112]
	Normal	Chloride diffusion	10% GP 10% fly ash	0.45	All mixtures containing glass sludge have lower values than the control mix with 20% fly ash. So it provided a better resistance to CP.	[51]
GA	Steel slag based	WA, WP	5%, 10%, 15% & 20% (FGA) 45% steel slag	0.40	WP lies in scale of medium penetration as per the stipulations of DIN-1048. The positive effect of FGA in steel slag based concrete was up to 10% substitution level.	[65]
	Normal	WA, CP, chloride diffusion	30%, 60% & 100% (FGA) volume 20% fly ash	0.53	The lower porosity and WA capacity of glass, compared with natural sand, poses a negative effect on chloride diffusion. Resistance to CP can be enhanced for concrete with FGA in long-term.	[78]
	Normal	WP, carbonation	15% (FGA) 25% & 30% steel slag, 30% fly ash, 8% & 10% silica fume	0.39–0.59	FGA mixes increased the permeability slightly compared to control mixes and had no effect on carbonation resistance.	[113]
	Normal lightwt.	Electrical resistivity	5% & 10% (FGA) 7% fly ash 7% slag	0.40	The lightweight aggregate concrete containing FGA had better electrical resistivity than control group, and higher than that of normal-weight concrete with the addition crumb rubber.	[114]
	Normal	RCPT, sorptivity	100% (FGA) 20% fly ash	0.42, 0.46, 0.48 & 0.57	At a similar W/C, glasscrete mixtures have lower sorptivity and lower chloride ion penetrability.	[115]
	Paving block	WA	100% (FGA) 25% fly ash	0.30	Using FGA improved resistance to WA.	[116]
	Normal	RCPT	25%, 50%, 75% & 100% (FGA) 25%, 50%, 75% & 100%steel slag	0.40	A replacement amount of 75% FGA was non-detrimental to a concrete mixture. The chloride permeability of this concrete was significantly lower than the control mixture.	[117]
GF	Normal	WA,RCPT	1% vol. fraction 30%steel slag, 15%fly ash 15%rice husk ash, 10% microsilica cement vol.	0.38	Combination of GF and mineral admixtures reduces the WA more than the sum of their single effects. The combined incorporation of any of the mineral admixtures with GF can significantly lower the RCPT compared to conventional mix.	[118]
	SCC	WA, WP, electrical resistivity	0.5%, 1% & 1.5% vol. fraction 0.5%, 1%, 1.5%, 2% & 3% nano aluminum oxide cement wt.	0.48	The utilization of GF alongside aluminum oxide nanoparticles decreased WA and WP compared to control specimens.	[119]
	HPC	Sorptivity	0.5% & 1% vol. fraction 15% microsilica	0.25	The sorptivity index values less than 0.06 mm/min1/2 were achieved for all mixtures. The use of microsilica decreased sorptivity index values.	[95]
	Normal	WA	0.5%, 1%, 1.5% & 2% cement wt. 5%, 10%, 15% & 20% silica fume	0.55	When GF was added to concrete in existence of coconut shell, it displayed good WA because it reduced the porosity and improved density	[44]
	Normal	WA,CP	0.5% vol. fraction 5% & 10% silica fume	0.40	Silica fume and fiber reinforcement sowed superior WA and CP resistance than reference concrete.	[45]
	Normal	WA,CP	0.5% vol. fraction 20% fly ash	0.50	At a given level of recycled coarse aggregate, concrete containing GF and fly ash showed slightly higher WA and CP depth compared to control concrete.	[63]
	SCC	WA, RCPT, electrical resistivity	0.01–0.06% vol. fraction 22–26% fly ash 0.5%, 1% & 1.5% silica fume	0.51 & 0.26	Results of GF in addition of fly ash and silica fume had better performance.	[59]
	Normal	WA,CP	0.5% vol. fraction 10% silica fume	0.40	Silica fume helped to reduce WA of fiber reinforced concrete by more than 20% compared to control mix. It also upgraded the CP resistance.	[82]
	Shotcrete	WA	0.5, 0.7 & 1% vol. fraction 1%, 1.5%, 2% & 2.5% nano silica 0.5% & 1% nano alumina	0.50	GF and nano materials reduced WA which will make it an appropriate protective layer on tunnel roof.	[99]
	SCC	WA,RCPT	0.10–0.80% vol. fraction 10%metakaolin	0.389	GF reinforced concrete showed reduced CP up to 0.6% of GF inclusion due to the good bonding of GF with binders. The inclusion of GF showed slight increase in WA when compared to control mix.	[120]
	Fiber reinforced	Electrical resistance	0.10% wt. fraction 20% & 40% fly ash	0.35	Electrical resistivity of samples containing GF and fly ash showed higher value.	[121]

shows the combined effect of RG and pozzolanic materials on transport properties. Fly ash and slag were the most pozzolanic material combined with GP, GA, and GF used by researchers. They showed effective results for water and chloride transports. Silica, metakaolin, zeolite, and rice husk ash were also used as pozzolanic materials combined with glass and showed good results.

As discussed earlier, adding additional pozzolanic materials to GP enhances the transport properties by the filling effect and pozzolanic activity leading to densifying the particles and reducing the pores. Furthermore, utilizing FGA and GF along with pozzolanic materials had an effective role in transport property. This is ascribed to the permeability resistance of the concrete of FGA, in addition to pozzolanic reaction of additional pozzolans that help in improving transport properties by filling pores.

4.4.2. Combined Effect of Recycled Glass and Pozzolanic Materials on Chemical Attack

Table 8. Combined effect of recycled glass and pozzolanic materials on chemical properties.

Glass Form	Type of Concrete	Chemical Property	Replacement/ Addition Ratio	W/C	Findings	Ref.
GP	UHPC	Sulfate attack	1%, 2% & 3% GP (addition) 15% silica fume (addition)	0.19	Strength loss of sulfate attack for samples containing GP and silica fume was extremely low compared with traditional concrete.	[111]
	Normal	Sulfate attack	10%, 20%, 30% & 40% GP 10%, 20%, 30% & 40% fly ash	0.485	The combinations of 10% ground GF with 30% fly ash and 20% ground GF with 20% fly ash were the optimal blending levels to improve performance of sulfate attack.	[46]
	Normal	Sulfate attack	10%20% & 30% GP 25% fly ash	0.45	Addition of ground GF significantly improved the resistance of mix against sulfate attack. The lower expansion values could be related to the refined microstructure of the paste.	[62]
GA	Normal	Acid attack, sulfate attack	5%, 10%, 15% & 20% (FGA) 45% steel slag	0.40	Slight change was observed in weight and compressive strength of FGA incorporated in mixes after exposure to acidic and sulfate environment.	[65]
	Normal	Sulfate attack	30%, 60% & 100% (FGA) 20% fly ash	0.53	The relative increase in compressive strength of concrete containing FGA was obviously larger than that of the control concrete under sulfate attack.	[78]
	Normal Lighttwt	Sulfate attack	5% & 10% (FGA) 7% fly ash 7% steel slag	0.40	After 5 cycles of sulfate immersion, the concrete specimen with a mixture of FGA had the best resistance to sulfate attack.	[114]
GF	HPC	Acid sulfuric attack	0.5% & 1% vol. fraction 15% microsilica	0.25	The sulfuric acid attack exerted a substantial influence on the mechanical performance of mixtures and the physical appearance.	[95]
	Normal	Acid attack	0.5%, 1%, 1.5% & 2% cement wt. 5%, 10%, 15% & 20% silica fume	0.55	When GF was added to concrete in existence of silica fume and coconut shell, it displayed good behavior under the acid resistance test.	[44]
	SCC	Acid attack	0.01–0.06% vol. fraction 22–26% fly ash 7% silica fume	0.51, 0.26	Fly ash or silica fume exhibited a good performance for the acid attack.	[59]
	Normal	Sulfuric acid attack	0.5% vol. fraction 20% fly ash vol. fraction	0.0.50	Acid attack resistance of concrete mixed with GF and fly ash was more than the corresponding PC mix.	[63]
	Normal	sulfate attack acid attack	0.4% vol. fraction 60% steel slag	-	Samples containing GF exposed to sulfate and acid attacks showed better compressive strength in comparison to control sample.	[80]
	Normal	Sulfate attack, acid attack	0.4% vol. fraction 40% fly ash	0.40	Samples containing GF exposed to sulfate and acid attacks showed better compressive strength in comparison to control sample.	[122]

shows the combined effect of RG and pozzolanic materials on chemical properties. Fly ash, slag, and silica were the most pozzolanic material combined with GP, GA, and GF used by researchers. They showed effective results for chemical attack resistance in terms of sulfates and acids. Fly ash along with GP have been used by [46,62]. Fly ash along with GA have been used by [78], while steel slag along with GA have been used by [65]; however, Ref. [114] used each of fly ash and steel slag along with GA. In addition, fly ash along with GF have been used by [59,63,122] while steel slag along with GF used by [80] and microsilica along with GF used by [95]. As disused earlier, GP, GA, and GF combined with pozzolanic materials result in the consumption of calcium hydroxide and reduction of calcium oxide of binder, which in turn could slow the process of degradation of concrete.

4.4.3. Combined Effect of Recycled Glass and Pozzolanic Materials on Freeze/Thaw

Table 9 shows the combined effect of RG and pozzolanic materials on FT. Fly ash along with GP have been used by [51] and proved good performance for FT. As discussed earlier, the combined effect serves as nucleation for air bubbles due to its angularity and finer particle size than ordinary concrete.

On the other hand, steel slag along with GA have been used by [117] and no significant change is reported, while silica fume and metakaolin along with GF have been used by [123] and the composite showed improved FT resistance in de-icing salt solution.

Table 9. Combined effect of recycled glass and pozzolanic materials on freeze/thaw.

Glass Form	Type of Concrete	Replacement/ Addition Ratio	W/C	Findings	Ref.
GP	Normal	10% GP 10% fly ash	0.45	Incorporation of 10% GP and 10% fly ash improved the resistance of concrete to FT cycles with and without de-icing salt (NaCl + CaCl2, 4% solution).	[51]
GA	Normal	25%, 50%, 75% & 100% (FGA) 25%, 50%, 75% & 100% steel slag	0.40	A replacement of 25% FGA, FT durability was equal to a control mixture. A replacement of 75% FGA, the FT durability was slightly lower than the control. A replacement amount of 100% FGA, The FT durability was very low.	[117]
GF	Glass reinforced concrete	2.9% wt. fraction. 2.5%, 5% & 7.5% silica fume 2.5%, 5% & 7.5% metakaolin	0.36	The composites showed very good FT resistance after 112 cycles in de-icing salt solution.	[123]

Table 9. Combined effect of recycled glass and pozzolanic materials on freeze/thaw.

Glass Form	Type of Concrete	Replacement/ Addition Ratio	W/C	Findings	Ref.
GP	Normal	10% GP 10% fly ash	0.45	Incorporation of 10% GP and 10% fly ash improved the resistance of concrete to FT cycles with and without de-icing salt (NaCl + CaCl2, 4% solution).	[51]
GA	Normal	25%, 50%, 75% & 100% (FGA) 25%, 50%, 75% & 100% steel slag	0.40	A replacement of 25% FGA, FT durability was equal to a control mixture. A replacement of 75% FGA, the FT durability was slightly lower than the control. A replacement amount of 100% FGA, The FT durability was very low.	[117]
GF	Glass reinforced concrete	2.9% wt. fraction. 2.5%, 5% & 7.5% silica fume 2.5%, 5% & 7.5% metakaolin	0.36	The composites showed very good FT resistance after 112 cycles in de-icing salt solution.	[123]

4.4.4. Combined Effect of Recycled Glass and Pozzolanic Materials on Alkali-Silica Reaction

Table 10 shows the combined effect of RG and pozzolanic materials on ASR. There is a general improvement in mitigating ASR expansion. Ref. [108] used ternary blend of GP, slag, and silica fume at different dosage levels and concluded this combined effect mitigates the ASR expansion of concrete samples. Refs. [46,62] used GP blended with fly ash. They report the combined pozzolanity of GP and fly ash reduced free Ca ions, and thus, the ASR gel was less expansive. Ref. [56] used GP with metakaolin and emphasized on the glass particle dimension to reduce the ASR.

Regarding GA, refs. [58,117] used zeolite and steel slag respectively. They found the pozzolanic effect mitigates these expansions to a negligible level.

Table 10. Combined effect of recycled glass and pozzolanic materials on ASR.

Glass Form	Type of Concrete	Replacement/ Addition Ratio	W/C	Findings	Ref.
GP	Normal	10% & 15%, 20% 10% steel slag 10% & 15% silica fume	0.47	Ternary blend of GP, slag, and silica fume at different dosage levels can successfully mitigate the ASR expansion of mortar and concrete samples.	[108]
	Normal	10%, 20%, 30%,& 40% 10%, 20%, 30% & 40% fly ash	0.485	The ASR was less expansive due to pozzolanic reaction and a less free Ca ions. The optimum combinations were 10% ground GF with 30% fly ash and 20% ground GF with 20% fly ash.	[46]
	Normal	10% & 20% 10% & 20% metakaolin	0.60	Use combined GP with metakaolin considering the glass particle dimensions reduced the occurrence of ASR.	[56]
	Normal	10%, 20%, & 30% 25% fly ash	0.45	At replacement levels of 20% and 30%, GP combined with fly ash was able to meet the expansion limit of 0.10% indicating its ability to mitigate ASR.	[62]
GA	SCC	15% & 25% (FGA) 10% & 20% zeolite	0.47	Replacing 20% of PC with zeolite was highly effective to control the deleterious expansion containing various size ranges of FGA.	[58]
	UHPC	50% & 100% (FGA) 22% silica fume	0.189	Incorporating 50% glass sand as quartz-sand replacement along with silica fume can yield a very dense microstructure and without any expansion from ASR.	[124]
	Normal	25%, 50%, 75% & 100% (FGA) 25%, 50%, 75% & 100% steel slag	0.40	The use of 50% steel slag with FGA as cementitious was found to mitigate these expansions to a negligible level.	[117]

Table 10. Combined effect of recycled glass and pozzolanic materials on ASR.

Glass Form	Type of Concrete	Replacement/ Addition Ratio	W/C	Findings	Ref.
GP	Normal	10% & 15%, 20% 10% steel slag 10% & 15% silica fume	0.47	Ternary blend of GP, slag, and silica fume at different dosage levels can successfully mitigate the ASR expansion of mortar and concrete samples.	[108]
	Normal	10%, 20%, 30%,& 40% 10%, 20%, 30% & 40% fly ash	0.485	The ASR was less expansive due to pozzolanic reaction and a less free Ca ions. The optimum combinations were 10% ground GF with 30% fly ash and 20% ground GF with 20% fly ash.	[46]
	Normal	10% & 20% 10% & 20% metakaolin	0.60	Use combined GP with metakaolin considering the glass particle dimensions reduced the occurrence of ASR.	[56]
	Normal	10%, 20%, & 30% 25% fly ash	0.45	At replacement levels of 20% and 30%, GP combined with fly ash was able to meet the expansion limit of 0.10% indicating its ability to mitigate ASR.	[62]
GA	SCC	15% & 25% (FGA) 10% & 20% zeolite	0.47	Replacing 20% of PC with zeolite was highly effective to control the deleterious expansion containing various size ranges of FGA.	[58]
	UHPC	50% & 100% (FGA) 22% silica fume	0.189	Incorporating 50% glass sand as quartz-sand replacement along with silica fume can yield a very dense microstructure and without any expansion from ASR.	[124]
	Normal	25%, 50%, 75% & 100% (FGA) 25%, 50%, 75% & 100% steel slag	0.40	The use of 50% steel slag with FGA as cementitious was found to mitigate these expansions to a negligible level.	[117]

5. Discussion of Findings and Future Directions

Based on the studies reviewed in this SLR, analyzing the results of the alternative types of RG were determined based on better substitutes and correlations with the chemical compositions and treatment processes. In addition, the valorization of RG has a positive impact on the durability of concrete; in addition, the mutual synergy of multiple substitutions of pozzolanic materials and glass manifests promising results.

After a comprehensive review of the effect of RG on the durability of concrete, it can be seen that RG can improve the durability of concrete, as compared to conventional materials. The addition of RG to concrete provides a higher resistance transport properties and chemical resistance by providing an extended lifespan through minimizing connectivity between voids/pores and thus preventing ion penetration and detrimental chemicals suppression. In addition, RG plays a great role for FT action in cold climate due to sharp angularity allowing existed air bubbles resist the cycles of FT. Furthermore, refinement of glass provides effective results for ASR to overcome the expansion and cracks of concrete. Consequently, glass is a promising material that can be used in the production of durable concrete to mitigate the negative effects of conventional construction materials such as cement and aggregate. Based on the analysis of the reviewed studies, the analytical framework highlights the durability improvement of glass-modified concrete, as seen in Figure 8. It could be adopted to present the different findings of previous studies and highlights the summary of effects of different forms of glass on the durability parameters of concrete.

As the quantities SiO₂, CaO, and Na₂O of WG differ according to the type of glass being manufactured. However, the alkaline oxides (CaO, Na₂O, and K₂O) aggravate the disorder extent of the amorphous structure. Hence, the pH value is increased in concrete pore solution because more alkaline hydroxide (Ca(OH)₂, KOH, NaOH) is generated. The increased OH⁻ ions help break the ≡Si-O-Si≡ bond and promote the dissolution of glass. The reactivity of the silica is based on the dissolution rate of the amorphous silica [21]. Thus, the pozzolanic activity of glass could be evaluated. As mentioned in the literature, soda lime glass has more alkaline oxides than other types, such as CRT glass. Most of the reviewed studies utilized soda lime glass for testing durability properties. It is critical whether the results could be applied to other types of glass rather than soda lime. To evaluate the pozzolanic performance of a specific GP, it is recommended for any research in the future to carry out chemical composition analysis to meet the minimum chemical requirement for pozzolans, determine the durability activity index and investigate the proper range of replacement levels for durability performances of concrete. The research should be directed to creating methods for manufacturing RG, specifically GP. Most of the reviewed studies have focused on using FGA rather than CGA as an aggregate substitute. Currently, FGA could be promoted to be used as a partial substitute for sand irrespective of chemical composition due to the ease of recycling process of glass because it is a safe, strong, and economical alternative to sand used in concrete [125]. As observed in the reviewed studies, FGA could be used as a 100% sand replacement. However, high ratio replacement of FGA is not practical for concrete production. Optimizing a practical percentage range of FGA without/with other pozzolanic materials, provided it does not compromise mechanical properties, is recommended since few studies have investigated its use as a fine aggregate.

The direction of using glass in concrete is challenging for the following reasons: difficulties in recycling process, complicated refinement process, and optimizing proper mix design for durable concrete. Nevertheless, GP could be obtained as a byproduct of manufacturing processes of glass plant by cutting and polishing resulted WG sludge. Refs. [51,68,87] used WG sludge as a cement replacement. In addition, GP could be produced by grinding GF, which is easier than crushing WG. Refs. [46,62] used ground GF as cement replacement. However, GF is strongly encouraged to be used in fiber concrete which is a material made of a cement matrix composed of cement, sand, water, and admixtures, in which short length GF are dispersed. It has many advantages over other fibers when it comes to economy and durability [82]. It could be widely used in the construction industry for non-structural elements, such as architectural decoration. On the other hand, RG could be used in various types of concrete; however, the performance of self-consolidating concrete mixtures becomes more reliable while GP is substituted [60].

6. Conclusions and Future Research

This SLR tried to highlight the current discussions on the effects of RG on the durability properties of concrete and analyzed the main parameters of the durability in experiments. Eventually, the test results reported by different researchers were compared and discussed based on the parameters. The current study has reviewed the durability of concrete with GP as a replacement for cement and GA as a replacement for aggregate or the addition of GF to concrete. The durability of concrete in terms of late hardening containing glass, specifically refined glass, can be improved over that normal concrete through the use of an appropriate mix design. Moreover, a concrete mix containing both glass and other pozzolanic materials exhibited improved durability compared to other mixes. Based on the review, the following concluding remarks can be drawn:

• Using glass particles to replace cement can further densify the microstructure of the mixture due to pozzolanic reaction and filler effect accompanied with extremely low permeability, therefore, improving durability properties. On the other hand, using glass particles to replace sand requires finding the proper glass particle size to ensure the particle packing density and prevent gap grading.
• Quality control of glass is essential to ensure the suitable selection based on physical and chemical characteristics and the purpose of applications. It is recommended to select the appropriate type, particle size, chemical composition, and replacement levels of RG to achieve adequate long-term durability of concrete and comparable mechanical strength depending on the intended applications.
• Glass, particularly refined particles, has shown improved and high resistance for transport properties indicated in this study, specifically WA, WP, and CP, which substantiates the concrete has low porosity and high density as a result of stronger bonding between GP and the cement paste. This is ascribed to the refined microstructure of both in the cement matrix and in the ITZ, as a consequence of pozzolanic and filling effects.
• Glass improves the chemical resistance improvement in terms of sulfates and acid attack of glass inclusion in concrete. GP could reduce of the total amount of tri-calcium aluminate hydrate in the concrete, which is responsible for the formation of ettringite; in addition, the pozzolanic reaction consumes part of the calcium hydroxides forming secondary C-S-H. On the other hand, GA and GF could improve the chemical resistance due to the reason of lower WA and high resistance of glass against sulfate and acid attack.
• Glass has a positive effect on the FT property. The effectiveness of glass is associated with angularity and finer particle size leading to a nucleation for air bubbles. The use of glass-modified concrete may be useful in cold regions as well as in places with high concentration of ions and salts.
• The ASR expansion is associated with the type, size, and content of glass. Using GA in concrete promotes ASR expansion. Inclusion of micro glass particle size is effective in ASR expansion. From this study, it may be concluded that the use of GP as cement substitution improves ASR. In order to compensate the negative ASR durability of concrete for GA, additional pozzolanic materials such as fly ash, slag, and silica fume with different combinations and quantities can be used in mix designs and trial batching.
• Up to 20% of PC and up to 30% of NA could be replaced with RG depending on W/C ratio as an important factor in controlling the durability of concrete. However, it has a significant effect on the roles of glass particle size and replacement percentage on the durability. This results in producing sustainable concrete with improved durability provided keeping reasonable strength development. Moreover, this would reduce consumption of PC and NA and relieve the pressure of landfilling.
• Other glass types rather than soda lime glass could be tested for durability of concrete. The pozzolanic activity of any glass type could be evaluated in regard to alkaline oxides and amorphous structure. Hence, the durability of concrete could be evaluated due to the pozzolanic reaction. Nevertheless, ASR may be affected by excess of alkaline of Glass.

To sum up, this review approach was adopted to provide new insights into the impact of the incorporation of glass with or without supplementary cementitious materials on the durability of concrete. This paper also aimed to provide several valuable insights on improving the quality of concrete and reduce the environmental impact. The results suggested that it is technically feasible to utilize glass as a part of concrete in the production of durable concrete. Strength properties should not be compromised when utilizing RG to enhance the durability of concrete. The long-term performance of glass-modified concrete could be utilized in structural elements and not limiting the applicability in non-structural concrete. Guidelines will be beneficial if followed the trends for various combinations of RG with other materials. Besides, the utilization of RG in concrete either GP, PA, or GF can be environmentally and economically viable caused by cement production and aggregate utilization. Incorporation of these by-products help protect environmental resources, which result in sustainable construction in the future.

This SLR would substantiate beneficial effects of glass use in concrete to enhance functionality and sustainability of concrete. Further work for understanding various properties of concrete such as creep, fatigue, shrinkage, thermal performance, and fire resistance should be carried out to ascertain how glass-modified concrete would satisfy high-performance concrete.