Utilisation of Different Types of Glass Waste as Pozzolanic Additive or Aggregate in Construction Materials

Abstract

Unprocessed glass waste is commonly disposed of in landfills, posing a significant environmental threat worldwide due to its non-biodegradable nature and long decomposition period. The volume of this waste continues to increase annually, driven by increasing consumption of electronic and household devices, as well as the growing popularity and end-of-life disposal of solar panels and other glass products. Therefore, to promote the development of the circular economy and the principles of sustainability, it is necessary to address the problem of reusing this waste. This review article examines the chemical and physical properties of various types of glass waste, including window glass, bottles, solar panels, and glass recovered from discarded electronic and household appliances. It was determined that the most promising and applicable reuse, which does not require high energy consumption, could be in the manufacture of concrete, which is the most developed construction material worldwide. Glass waste can be incorporated into concrete in three different particle sizes according to their function: (a) cement-sized particles, used as a partial binder replacement; (b) sand-sized particles, replacing fine aggregate; and (c) coarse aggregate-sized particles, substituting natural coarse aggregate either partially or fully. The article analyses the impact of glass waste on the properties of concrete or binder, presents controversial results, and provides recommendations for future research. In addition, the advantages and challenges of incorporating glass waste in ceramics and asphalt concrete are highlighted.

1. Introduction

Glass is one of the most common materials in the world. Therefore, a wide range of glass products is manufactured for a variety of applications, such as packaging glass for bottles, household appliances, liquid crystal displays, optical devices, and solar panels, among others. The properties of these different glass products vary significantly [1]. As global glass production and consumption increase annually, so does the amount of glass waste (GW) of all types [2,3,4,5,6]. This is due to the fact that recycling rates remain low, at a maximum of 35% in general, and the focus is limited to the recycling of glass containers and packaging [4,7]. In the United States, the volume of glass containers was recorded at 3.1 million tons in 2018, with a recycling rate of only 31.3% [8]. The highest recycling rates for GW have been recorded in Europe. In 2018, the Federation of European Recycling of Glass (FERVER) found that the overall recycling rate for glass in Europe was 70%, rising to 76% in 2020 [9]. In Australia, the generation of waste glass has increased by 43% since 2014. Between 2017 and 2018, 1.1 million tons of waste glass were generated, of which 57% were recycled. However, only a small proportion of nonrecycled glass was used for other products, such as concrete aggregates [3,10]. In 2018, the glass recycling rate in China was approximately 1.1 billion, which represented 53.5% of the total GW generated. However, the remaining 46.5% was disposed of in landfills [4,11]. As a result, since the beginning of 2018, China has prohibited the importation of various categories of GW. Similarly, Australia has decided to ban the export of waste tyres, plastics, paper and glass from 2021 [10,12]. Furthermore, recent studies indicate that photovoltaic panel (PVP) production accounted for 95% of total production in 2020 and over the last two decades has maintained a market share of nearly 90%. The expected lifetime of a PVP is approximately 25–30 years [13]. The projections indicate that the amount of waste generated by PVP will reach 1.7–8 million tons by 2030 and will continue to increase to 60–78 million tons by 2050 [14]. This substantial amount of waste will pose significant challenges both to the environment and to the global economy, requiring researchers to develop effective recycling technology systems [15].

However, at the end of their lifecycle, glass products can undergo a screening, sorting, and recycling process, subsequently allowing the production of new glass products. To illustrate, recycling one ton of glass saves approximately 590 kg of sand, 186 kg of soda ash, 172 kg of limestone, 19 l of fuel, 3.4 kg of air pollutants, and 42 kW/h of energy [4]. However, the heterogeneity of glass types, colours, and impurities poses significant challenges to glass reuse, often leading to the disposal of waste glass in landfills [16]. For example, glass recovered from municipal solid waste is used in the production of glass bottles. Typically, up to 60% of each new glass bottle is made from recycled glass. This process is repeated for a limited period of time, after which the glass is usually disposed of in landfills due to the high level of contamination [17]. The presence of GW in landfills constitutes a danger to the global environment due to its unique chemical composition and structure [18], its nonbiodegradable nature, and the inherent difficulties associated with its recycling process. To ensure the preservation of natural resources, reduce landfill space requirements and financial expenditures, as well as minimise energy consumption [7,10,19], addressing these challenges is imperative.

For many decades, GW has been utilised globally, primarily to produce glass fibres and blown glass pellets. These products, however, cannot absorb the significant amount of glass waste produced on a global scale [10]. On a worldwide basis, the prospect of recycling non-containerised waste glass is being investigated for a multitude of applications, for instance in asphalt pavement aggregates, aggregates used in concrete production, replacement of cement in certain formulations, glass tile fabrication, and the production of glass fibre insulation materials [19,20,21,22]. According to the literature, crushed GW can be used as a fluxing agent to reduce the firing temperature in the production of ceramics. Beyond this, it can also be used as an additive for clay and glass aggregates in the context of building construction. Moreover, this waste can be used in the production of glass ceramics [3,23].

Furthermore, in recent decades, humanity has faced climate change and increased CO₂ emissions, making the utilisation of alternative resources a primary subject of research. The construction sector has been identified as the main contributor to CO₂ emissions, ranking as the third-largest source of anthropogenic carbon dioxide emissions. This is particularly due to CO₂ emissions from cement production [24]. Consequently, there has been a surge in research efforts aimed at exploring alternative materials to replace cement. Among these materials, the use of recycled glass as a pozzolanic additive to replace part of the cement has received significant attention. Alternatively, glass could be used as an aggregate, replacing part of fine or coarse natural aggregates in mortars and concrete [25,26,27]. Omran et al. [28] investigated the effect of bottle glass on the durability of concrete when used outdoors for pavements, walls, etc. Their findings suggest that the incorporation of waste glass leads to an improvement in the long-term compaction of the concrete microstructure, thus increasing its durability, compressive and flexural strength, as well as other mechanical and physical properties. In contrast, the utilisation of glass waste as a concrete aggregate depends on its inherent characteristics, such as its granulometry, particle shape, chemical composition, and reactivity. In a study by Khmiri et al. [29], the pozzolanic activity of container GW was evaluated for its potential application as a partial replacement of cement in concrete. Their findings indicated that the waste glass exhibited comparatively high pozzolanic activity when its particle size was less than 20 μm, in contrast to other glass particle sizes ranging from less than 40 μm to 100 μm. Given the high content of amorphous silica in glass waste, which is essential for pozzolanic activity, there has been an increase in research on the use of glass powder in concrete production. In addition to silica, the high concentration of alkali metal oxides in glass (mainly sodium oxide and calcium oxide) plays an important role in the performance of concrete containing waste glass, due to the potential alkali–silica reaction (ASR) [30]. Rajabipour et al. [31,32] conclude that the reactivity of a material depends on the type of silica mineral it contains, the size and distribution of these minerals, and the amount of calcium that reacts with silica. In general, an increase in the fineness of glass particles has been shown to increase the pozzolanic activity and inhibit the expansion of concrete due to ASR [33,34]. It is imperative to investigate how different glass chemistries influence concrete properties by promoting or inhibiting pozzolanic activity and/or ASR [35]. The combined effects of pozzolanic reactivity and the alkali–silica reaction (ASR) have a significant impact on the various mechanical properties and durability of cementitious materials with waste glass. To mitigate the adverse effects of ASR, proactive measures can be implemented by incorporating a suitable pozzolanic material, such as fly ash, microsilica fume (MSF), or ground blast furnace slag, into the concrete mixture in optimal proportions [19].

Furthermore, global observations have documented the impact of the construction sector on natural resources in the production of aggregates for cementitious materials. The primary natural aggregates used in construction are crushed stone, gravel, and sand [36]. Between 32 and 50 billion tons of sand and gravel are estimated to be extracted worldwide each year, utilised mainly in construction [37]. However, global studies have shown that sand extraction far exceeds its regeneration rate, potentially compromising ecosystem integrity and causing problems such as loss of biodiversity, beach erosion, and landscape degradation [37,38]. One potential solution to reduce the consumption of natural sand is the use of recycled waste as an alternative material. Specifically, the use of glass waste as an alternative to sand in cementitious materials. Providing a promising way to reduce the demand for natural sand. Typically, GW particles have a rough surface, and their geotechnical parameters are analogous to those of natural aggregates [39].

The objective of this study is to examine the differences in the chemical composition of the different types of GW, their different effects on properties, and the potential opportunities for their reuse in the construction materials industry in the context of the development of the circular economy and the principles of sustainability.

2. Research Methods

In the scientific articles analysed, the properties of the materials were determined by standard methods. The chemical composition of the GW was determined by using an X-ray fluorescence spectrometer (XRF) and the mineral composition by an X-ray diffractometer (XRD). The average particle size of the milled GW was investigated using laser diffraction. To determine the leaching of harmful substances, the samples were prepared according to EN 12457-2 [40] in a 10 L/kg water–solid ratio, with a particle size below 4 mm. The amount of Ca(OH)₂ was determined by thermogravimetric analysis based on the mass loss that occurs approximately between 430 and 550 °C. The reactivity of GW was evaluated according to ASTM C1260 or an Australian method, RTA T363 AMBT or RILEM recommendations, keeping the samples in 1 M NaOH at 80 °C for 14–28 days and recording the changes in dimensions.

Concrete consistency tests were carried out according to EN 12350-2 [41]. Concrete samples were made and cured for strength tests according to EN 12390-2 [42]. The density was tested according to EN 12390-7 [43], and the compressive strength was tested according to EN 12390-3 [44]. Water penetration depth tests were carried out under pressure in accordance with EN 12390-8 [45]. Rapid chloride permeability was determined according to ASTM C 1202 [46] and a non-steady-state migration test according to NT Build 492. The flexural and compressive strength of cementitious stone and mortars was determined according to EN 196-1 [47] or EN 1015-11 [48] standards. The density, water absorption, and consistency of mortars were calculated according to EN 1097-3 [49], EN 1097-6 [50], and EN 1015-3 [51], respectively.

In this study, the grouping and analysis of literature data were performed using Excel (Version 2108, Build 14332.21017) and Statistica 8 (version 8.0.360.0) software.

3. Results and Discussion

3.1. Chemical and Physical Properties of Different Types of GW

Glass is classified as an amorphous solid. Its composition is determined by the bond energy (BE), network formers (NF), network modifiers (NM), and incorporation of various additives. These components are considered the primary elements that define the structure and properties of glass [11]. From a chemical perspective, glass is made up of metal oxides that are melted and subsequently cooled to form a solid substance. Glass demonstrates notable chemical resistance, showing minimal reactivity with a wide range of common chemicals. These properties make glass highly suitable for various applications, such as packaging, laboratory supplies, and other contexts where chemical resistance is imperative [52]. Glass classification is based primarily on its predominant composition, with the most common classifications, including soda–lime glass, borosilicate glass, lead glass, barium glass, and aluminosilicate glass [20]. Figure 1 provides a comprehensive representation of the chemical composition of various glasses, categorised according to their classification. It is evident that the amounts of calcium, silicon, alumina, and magnesia exhibit significant variation between the diverse categories of glass. In general, silica (65–75%) constitutes the main component of the main segregated container waste, followed by sodium oxide (12–15%), calcium (6–12%), and alumina (0.5–5%) [11].

Glass is not homogeneous; rather, it is composed of disparate components that influence its properties. For example, the presence of substances that dissolve easily in water or react with other materials can compromise its durability and longevity. However, in certain circumstances, the various components of glass can combine to create a more robust and resilient structure. Borosilicate glass is a notable example of a material that is characterised by a substantial boron content (10–15%), resulting in the presence of a boron glass phase. This phase is susceptible to leaching or the formation of water–soluble alkaline molybdate compounds. In contrast, in silicon-rich borosilicate glass, phase separation can increase the durability of the glass if a durable silicate phase containing dispersed boron phases is formed. Even in the absence of phase separation, microheterogeneity may occur [53]. It is of significant concern that certain types of glass, predominantly those originating from household appliances and electronic waste, have been found to contain heavy metals, such as lead. This is particularly worrying when such glass is utilised in cement and concrete, as it can potentially result in the leaching of hazardous chemical elements into the surrounding environment [20,54].

A chemical analysis of plain bottle glass revealed that the chemical composition of powdered glass is primarily SiO₂ (68%), CaO (14.5%), and Na₂O (12.2%) [55]. The chemical composition of window glass was found to be 71.7% SiO₂, 13.6% Na₂O, and 8.4% CaO, with minor impurities, such as 0.07% TiO₂ and 0.25% SO₃. The composition of the base of the glass light bulbs consists of 73% SiO₂, 17% Na₂O, 5% CaO and 4% MgO. The sheet glass strongly resembles the composition of lightbulb glass, with a composition ranging from 71 to 73% SiO₂, 12 to 15% Na₂O, 8 to 10% CaO and 1 to 3.5% MgO [2,5,56]. However, a chemical analysis of waste liquid crystal display (LCD) glass has shown that it may contain about 65% organic compounds and only about 25% SiO₂, 5–10% Al₂O₃, 3% Ca, and other metals found in low amounts, such as As, Zn, Sr, Ba, P, K, Fe, Ti, Cu [57]. Research [58] has demonstrated that, subsequent to organic fraction separation, the SiO₂, Al₂O₃, and Fe₂O₃ amount in LCD glass exceeds 85%, thereby meeting the minimum requirement for pozzolanic material as outlined in ASTM C618 [59]. The chemical composition of solar panel (SP) waste glass was found to be 73.0% SiO₂, 0.6% Al₂O₃, 6.3% CaO, 18.2% Na₂O, 1.3% MgO and 0.1% Fe₂O₃. Given that the primary objective of SPs is to achieve maximum light transmittance to optimise power generation efficiency in a solar module, elevated SiO₂ content is a notable characteristic [60]. It should be noted that the presence of Ca, Mg and Zn enhances the durability of the glass by stabilising its structure. This stabilisation occurs through the formation of polygonal compounds around Ca, Mg, and Zn, which facilitate the bonding of oxygen atoms to silicon [61].

A detailed examination of the mineral composition of the glass revealed a distinct broad halo of amorphous phase between 2θ 15° and 35°, suggesting that this glass, similar to most other glasses [60], is composed of amorphous phases [57,58]. The amorphous crystalline phases indicated in the X-ray diffraction (XRD) curves may also be related to the increased pozzolanic activity of the glass, which leads to the formation of a higher content of calcium hydrosilicates (C-S-H) when reacting with cement [62]. XRD analysis of LED glass revealed the presence of an amorphous phase at 2θ 18–28°, along with significant crystalline components, mainly SiO₂ [63].

The physical properties of the crushed glass particles are typically found to have a particle density of about 2.5 g/cm³, a bulk density of about 1.4 g/cm³, and a water absorption of 0.4 wt.%. It exhibits high bulk stability up to 700 °C, with a thermal expansion coefficient and softening point of 8.8–9.2 × 10⁻⁶ cm/°C and 718–738 °C, respectively [64]. Its shape index (%) is 30.5, and its flakiness index ranges from 84.3 to 94.7 [54,65]. Furthermore, the glass is classified as alkaline, with a pH of approximately 11 [66]. The specific gravity of the window glass was determined to be 2.6 g/cm³, while its water absorption was found to be approximately 1.0% [67]. In the case of container glass (i.e., bottles and packaging), it has been observed that the physical properties vary depending on the colour of the glass. Specifically, brown and clear glasses have higher pozzolanic reactivity compared to other colours. However, the reason for this difference has not yet been elucidated [68]. Container glass particles are typically angular in shape, with the potential for flat and elongated particles. The degree of angularity and the proportion of flat and elongated particles depend on the extent of processing, specifically the crushing stage. It should be noted that the presence of smaller particles, a consequence of additional comminution, results in a slight reduction in angularity and an increase in flat and elongated particles. Proper shredding can virtually eliminate sharp edges and the corresponding safety hazards associated with manual handling of the product. Container GW, in contrast, exhibits significantly more variability in its properties, with particle density ranging from 1.96 to 2.52 g/cm³ [69]. Studies on SP glass show that it exhibits a water absorption rate of more than 5%, a particle density ranging from 2.1 to 3.2 g/cm³, a silt content of less than 3%, and a pH of 10.7 [70,71].

Given the chemical composition and physical properties of GW, it is vital to analyse the effects of different glasses on the properties of building materials separately.

3.2. The Influence of Different Particle Size Glass Waste on the Properties of Cementitious Materials

Glass waste has the potential to be used as fine or coarse aggregate in concrete or mortar mixtures, thus replacing sand, gravel or crushed stone. Therefore, research is underway to investigate the feasibility of dispersed glass partially replacing cement. These studies are especially important due to the very high CO₂ emissions during clinker manufacturing, which can be reduced during the production of blended cements. However, the findings from these studies have been inconsistent, highlighting the need for further research on GW with significantly divergent chemical compositions. For example, there is a paucity of consensus on the modulus of elasticity of concrete that contains glass waste. Callaghan et al. [72] observed an increase in modulus with increasing glass content, while Paul et al. [30] reported a decrease and etc.

3.2.1. Influence of Cement-Sized Glass Waste, Used as a Partial Binder Replacement, on the Properties of Cementitious Materials

The main results of the properties of cementitious materials by replacing a part of cement with different types of GW are presented in Figure 2, Figure 3 and Figure 4 and

Table 1. The influence of different types of cement-sized GW on cementitious material properties.

Type of Glass	Replacement of Cement, %	Slump	Porosity %	Density	Chloride Permeability	ASR	References
Bottle glass	30, 50, 70	↓					[73]
	5, 10, 15, 20, 25	↑					[66]
Soda-lime glass	15, 30, 45, 60		↑				[76]
Window glass sheets	10				↓		[78]
Industrial glass	10, 20				↓		[93]
E-waste glass	20	↑↓		↓			[80]
CRT glass	5, 10, 15, 20, 35		↓	↓			[81]
CRT and mixed container glass (MRF)	20				↓		[82]
LCD glass	5, 10, 15, 20, 30				↓	↓	[85,94]
LCD, LED TV screen and washing machine glass (WM)	5, 10, 20	↓↑		↓			[86]
Household appliance glass	10, 20, 30	↓		↓			[87]
Milled window glass	20	↑		↑			[89]
Fluorescent lamp glass	20, 30, 40	↓					[90]
Photovoltaic solar panel glass	0,3, 1, 3, 5			↓			[92]

. The compressive strength of cementitious materials, as the main characteristic presented in all scientific works analysed, has been observed to increase when 10–15% of the cement is replaced with GW (Figure 2). In rare cases, up to 20% replacement has been known to improve compressive strength. However, different types of GW can result in a significant reduction in strength, for example, 10% old TV screen GW results in a reduction of up to 30%. A statistical analysis of the data (Figure 3), regardless of glass type, indicated that when using up to 20% GW, the compressive strength can be comparable to that of the control sample. However, further increases in GW content result in a marked decline in strength.

The water absorption results of cementitious materials (Figure 4) demonstrate that GW generally reduces water absorption when the replacement level is up to 20%. However, further increases in GW content lead to higher water absorption due to the formation of GW agglomerates and increased open porosity of the material [87]. A particularly notable increase in water absorption was observed when the GW photovoltaic solar panel was used. This type of GW frequently contains various organic impurities and metals, especially aluminium, which react with the alkaline environment to release hydrogen gas, thereby increasing open porosity and, consequently, water absorption.

In Table 1 shows the impact (improve or reduce) of different GW on the slump, porosity, density, chloride penetration and ASR of cementitious materials. The results vary according to the amount and type of GW.

The results indicate that, irrespective of the type of GW used, the substitution of a part of cement with GW during the initial curing period typically leads to a deceleration of cement hydration, a reduction in density, and a decline in strength. However, an increase in curing time has been shown to result in enhanced compressive strength [63], reduced porosity and water absorption, and the formation of a more compact cementitious material structure [60,79,80]. This, in turn, has been demonstrated to enhance resistance to chemical corrosion [60,79,80] and even to freeze–thaw cycles [62,89]. These effects become more pronounced with increasing fineness of glass particles [63]. The mineral composition of the samples is also of significant interest, as evidenced by the existing literature. Specifically, samples in which part of the cement has been replaced by GW have a lower content of cementitious minerals and portlandite (Ca(OH)₂). In some cases, the content of Ca(OH)₂ may be much lower than the amount of cement replaced. This suggests that GW acts as an active pozzolanic additive, reacting with Ca(OH)₂ to form various types of C-S-H, the amount increasing with extended curing time. SEM studies have shown that, after 28 days of curing, the control sample is predominantly composed of Ca(OH)₂, while the incorporation of GW leads to the formation of a SiO₂ layer on the surface of the particle. Subsequently, this layer reacts with Ca(OH)₂ to produce C-S-H. After observation, a contributing factor to the reduced strength of samples containing GW [89,95] could be the presence of an interfacial transition zone (ITZ) between the glass and the cementitious matrix.

The reduced strength of cementitious materials with GW may also be attributed to the poor distribution of the dispersed glass throughout the sample and the likely formation of agglomerates [87]. The agglomerate areas under consideration are partially filled with C-S-H and become barely visible after 90 days of curing. This is due to the growth of crystalline hydrates in various forms during the cement hydration process, filling most of the voids [87]. The formation of additional C-S-H resulted in a more compact structure of cementitious materials as well as an increased resistance to environmental impacts [94]. In addition, particularly within the ITZ, the microstructure of the concrete, between the aggregate and the cement paste, experiences densification, increased homogeneity, and a more uniform distribution of phases. Although the replacement of the active binder has been shown to reduce the rate of cement hydration [75], the high fineness of the GW contributes a micro-filler effect, therefore offsetting the reduction in compressive strength caused by binder dilution [75]. It has been noted that in samples with more than 30% GW, the portlandite content becomes inadequate for the additional pozzolanic reaction [76,83]. Due to this, it is recommended to use no more than 10% GW or to incorporate additives capable of accelerating the hydration of cement, e.g., silica fume [77]. This approach can also lessen the adverse developments associated with ASR [53,78,94]. It has been established [35] that increasing the number of glass formers to glass, further reduces the reaction between alkali and silica (glasses of soda lime and fluorescent lamps). On the contrary, the presence of glass modifiers, for example, fluorescent lamp glass, has been found to impede the pozzolanic reaction. A comparison between soda–lime and fluorescent lamp glasses reveals that the former has a higher content of Na₂Oeq + PbO and a lower content of glass stabilisers (CaO + MgO). This yields a high degree of sodium dissolution, which is also associated with the formation of the ASR gel. This, in turn, leads to a change within its chemical composition and a consequent deterioration of its mechanical properties [90]. Additionally, the study observed that mortar containing crystalline glass (and PbO) exhibited the highest degree of expansion, regardless of whether glass was used as a substitute for a part of cement or for a fine aggregate [96,97]. It is noteworthy that the utilisation of solar panel glass that has not been thoroughly cleaned may pose challenges due to the occurrence of early-stage reactions in an alkaline environment, further resulting in the release of hydrogen and the subsequent expansion of the material [92]. Therefore, J. Zhao et al. [98] investigated an alkaline-activated binder consisting of solar panel waste glass powder, and blast furnace slag (used in a ratio of 1:1.5 with a w/b of 0.4) adding different shrinkage-reducing additives to the mixtures, such as CMEA (3–9%), HPMC (0.2–0.6%) and PAM (0.5–1.5%). Microstructural analysis showed that for all blends, the main hydration products were C-(A)-S-H gels and calcite, while PAM provided a more compact matrix. Walczak [99] investigated the possibility of using glass as a substitute for cement in the production of autoclaved aerated concrete. It was found that porous concrete can be created by adding different types of glass. Such concrete that incorporates cathode ray tube (CRT) glass had a compressive strength very similar to that of the control samples [100].

However, the underlying causes of the controversial effects of GW on the properties of cementitious materials remain unclear. Consequently, future research should focus on analysing the influence of the chemical and mineralogical composition, as well as the morphology of different glass types, on the performance of cementitious materials. Furthermore, efforts must be made to optimise the cement replacement rate through the use of additives or blends of various types of glass, which have the capacity to mitigate the detrimental effects of GW.

3.2.2. Influence of Fine Aggregate-Sized Particles, Used as a Partial Fine Aggregate Replacement, in Cementitious Materials

The main results of the properties of cementitious materials by replacing a part of fine aggregate with different types of GW are presented in Figure 5, Figure 6 and Figure 7 and

Table 2. The influence of different types of fine aggregate-sized glass waste on the properties of cementitious materials.

Type of Glass	Replacement of Sand, %	Particle Size	Slump	Porosity	Density	Chloride Permeability	ASR	Elasticity	Flexural Strength	References
Container glass	5, 10, 15, 20	<4.75 mm	↓		↓					[100]
	20, 40, 60	<4.76 mm	↑							[101]
	0, 18, 19, 20, 21, 22, 23, 24	150–600 µm		↑	↓				↑	[102]
	15, 30	<4.75 mm		↑				↓		[103]
	10, 15, 20	0.15–4.75 mm	↓		↓				↑	[104]
	15, 20, 30, 50	<5 mm	↓							[105]
Container glass	25, 50, 70, 100	<5 mm							↓	[106]
	25, 50, 75, 100	<600 μm	↑						↓↑	[107]
	10, 20, 30, 40, 50	0.075–5 mm	↓					↓	↓	[108]
LCD glass	20, 40, 60, 80	<4.75 mm	↓			↓				[111]
	10, 20, 30	<3.37 mm	↑			↓			↓↑	[112,113]
CRT glass	50, 100	<5 mm	↑					↓	↓	[115]
	20, 40, 60, 80, 100	<4.75 mm						↓	↓	[118]
	25, 50, 75, 100	0.6–1.18 mm		↑					↓↑	[119,126]
Various e-waste glass	10, 20, 30, 40, 50	<4.75 mm	↓							[120]
	5, 10, 15, 20	<4.75 mm		↓				↑		[127]
Photovoltaic solar panel glass	20, 80, 100	<4.75 mm					↓			[121]
	100	<4.75 mm	↑							[122]
Fluorescent lamp glass	10, 20, 30, 40	<1.18 mm					↑		↓	[123]
	10, 30, 50, 100	<2 mm, 2–8 mm	↑	↑	↓					[124]
	100	∼10–20 μm					↓			[125,128]
	12.5, 25, 37.5, 100	<100 μm							↑	[129]

. When evaluating the influence of GW content on the compressive strength of cement-based materials (Figure 5 and Figure 6), it is evident that partial replacement of sand, particularly up to 30% can improve compressive strength. To illustrate this point, replacing the sand with a container GW replacement level of 75% resulted in a 27% increase in the compressive strength of fine-grained concrete. This enhancement can be ascribed to the advantageous chemical and physical characteristics of container GW, including its relatively uniform particle size and angularity. These characteristics can promote effective particle packing and enhance the interfacial bond with the cement matrix. However, it should be noted that not all types of GW produce equivalent results. The CRT GW or GW from photovoltaic solar panels decrease compressive strength by about 15–20%. This decline is probably attributable to several factors. First, it is important to note that both CRT and photovoltaic solar panel GW often contain impurities or coatings (e.g., lead, rare earth elements, anti-reflective layers). These impurities or coatings can interfere with cement hydration or adversely affect the microstructure. Secondly, the morphology and surface texture of these types of glass can hinder effective bonding with the cement paste, leading to the formation of a weak ITZ. Statistical analysis of the data indicates that, in most cases, there was a decrease in compressive strength of up to 20% when less compatible types of GW were used. This suggests that the type and origin of GW play a critical role in determining its suitability as a partial replacement for sand in cementitious materials.

In addition to strength performance, different types of GW also significantly affect water absorption behaviour (Figure 7). For example, experimental findings demonstrated that CRT glass exhibited a 25% reduction in water absorption, a phenomenon attributed to its dense structure and low porosity. On the contrary, GW derived from fluorescent lamps markedly increased water absorption by several times.

It can be concluded that the partial replacement of fine aggregate with GW can result in either an increase or decrease in compressive strength of cementitious materials, depending on the type of GW used. Researchers illuminate the reduction in compressive strength of cementitious materials through several statements: (1) Sharp edges and smooth particle surfaces result in poorer adhesion between cement mortar and glass particles in ITZ [18,54,130,131,132,133]; (2) The increase in the water content of glass aggregate mixtures is attributed to the poor water absorption capacity of GW [54,134]; (3) Cracks due to the escalating stress resulting from the reaction between alkali and silica [133] are a possible concern. Finally, the cracks and voids in the concrete matrix increase with the elevated GW content. However, some articles claim that the GW additive increases mechanical strength. This improvement is mainly due to the surface structure and strength of the GW particles in comparison to natural sand [135,136,137] and the pozzolanic reaction of the smaller GW particles [77,138]. Consequently, changes in the strength of cementitious materials are highly dependent on the chemical composition, the shape, and other properties of different types of GW. Several studies have been carried out regarding the influence of GW colour on cementitious materials properties; some of which have reported that when GW is used as an aggregate, the colour does not cause a noticeable change in strength [139,140]. Alternatively, Tan and Du [76] reported that transparent GW exhibited lower strengths. According to the findings of the studies [138,141,142], it is recommended that GW content ranging from 10% to 20% be incorporated, which, compared to control samples, can result in an increase in compressive strength. Research indicates that the incorporation of GW in concrete results in a reduction in tensile strength; however, more research is needed to provide a more robust and comprehensive understanding of this phenomenon. Researchers attributed the phenomenon to inadequate adhesion between the cement paste and the glass particles, akin to compressive strength. Nevertheless, there were articles [70,103,106,107,116,120,125,143,144] in which the tensile strength of concrete, where 25% to 100% of the sand had been substituted for GW, was higher than that of the reference sample. This occurrence may be attributable to the incorporation of steel fibres. Although the flexural strength of concrete typically decreases with the use of GW, there are scientific articles that have shown [138,145,146] that the flexural strength of concrete has increased. Contradictory results have also been obtained regarding the modulus of elasticity (MOE) of concrete, which is mainly dependent on the MOE of the aggregates used, the cement matrix, and their relative proportions within the mixtures [55]. Incorporation of GW aggregates in concrete has been shown to improve the modulus of elasticity [6,100]. In contrast, several studies have reported that GW has the potential to reduce the MOE of concrete. On account of these studies, it can be concluded that the differences in the mechanical properties of cementitious materials may be related to a multitude of factors, including the type, size, shape, crystalline, and liquid phase content of the GW used in the mixtures, and the composition of the cementitious materials themselves, etc. Therefore, as the mechanisms by which concrete interacts with the binder change, the properties of concrete and other cementitious materials are affected.

In the literature, two parallel approaches have been identified in regard to the slump (workability) of concrete containing GW (Table 2). A substantial body of scientific research has demonstrated that the incorporation of GW into concrete mixtures improves workability. This occurrence has been attributed to a decrease in the cohesion between cement mortar and smooth surfaces of GW [113,147,148,149]. The significance of smooth surfaces and the low absorption of GW in improving workability has been well analysed [147,150]. Improvement in workability is a notable benefit of incorporating GW [151,152,153], aiding in decreasing the need for costly superplasticisers in certain cases [154,155,156,157]. However, some studies have reported that the inclusion of GW in the mixtures has reduced their workability. This reduction has been correlated with the presence of sharp edges, an increased aspect ratio of glass particles, and an angular shape that disrupts the free flow between the particles and the cement mortar [129,158,159,160,161].

The authors agree that there is a reduction in the density of cementitious materials with GW, a reduction attributable to the lower density of GW compared to natural aggregate [132,158,162], as well as the lower GW particle density [54,104,130,162]. In contrast, the fresh mix density of GW-containing concrete can exceed the reference density. This phenomenon is likely attributed to a higher density of the glass used, compared to the fine aggregate [137,163,164]. Fine glass exhibits pozzolanic activity, leading to a reduction in porosity, water absorption, and impermeability of cementitious materials over time. This activity improves the resistance of these materials to chloride and sulphate attack, the resistance to freeze–thaw cycles, and reduces thermal conductivity due to glass impermeability and its low water absorption capacity [117,165,166,167,168].

Furthermore, the use of GW aggregate in concrete has been shown to mitigate drying shrinkage [14,130,150,169]. Primary factors contributing to this decrease in drying shrinkage include negligible water absorption [170,171], reduced porosity [171], and increased modulus of elasticity of glass aggregates [170]. Another assessment of the relatively low drying shrinkage could be expansion due to the formation of ASR gel, which counterbalances the drying shrinkage of concrete. Kashani et al. [172] investigated the drying shrinkage of concrete foam samples with glass aggregates and observed similar trends of ASR expansion counteracting drying shrinkage of the samples. A review of the literature indicates that the extent of expansion due to ASR depends on the type of glass, the level of sand replacement, and the granulometric composition of GW. It is evident that the degree of expansion is amplified in instances where the GW content is increased. This phenomenon can be attributed to the increased presence of siloxane groups when subjected to alkali, which subsequently forms the ASR gel. Regarding the chromatic properties of the glass, it has been determined that clear glass generates the most significant expansion of the ASR, a finding that contrasts with the observations reported for green and brown glass [173,174,175]. Green glass exhibits the lowest degree of expansion among all known glasses due to the presence of chromium [133,174]. This eventuality can be explained by the “double-layer repulsion theory” proposed by Prezzi et al. [176]. This theory exemplifies the observed expansion of mortar rods, which is primarily driven by swelling as a result of the electric double-layer repulsive forces [176]. As with other GW filler materials that have been the subject of research, the results of this study are not entirely consistent. For instance, Dhir et al. [34] reported that clear (cream) glass exhibited optimal properties and minimal expansion, while green glass resulted in the greatest expansion. Such discrepancies may be attributed to several factors: (1) variations in the glass comminution process; (2) the presence of microcracks in the glass particles that may impede the ASR gels, resulting in comparatively diminished expansion; (3) the phase composition of the glass that may be a relevant factor. Alkalis may also be a factor, as may the incorporation of air, or the use of a porous lightweight filler, which has been demonstrated to be an effective method of reducing or eliminating expansion [32,34,99,173]. The pozzolanic reactivity of glass powders is contingent upon their chemical and mineralogical composition, with particular emphasis on the particle size. It has been demonstrated that the pozzolanic reactivity of glass powders increases with decreasing particle size, resulting in a greater ASR reduction. Amorphous silica has been shown to be susceptible to corrosion at ambient pH levels exceeding 12 [20]. The pH of a Ca(OH)₂ saturated solution at 20 °C is approximately 12.4. Consequently, the pH of low-alkaline Portland cement is sufficiently elevated to induce corrosion of soda–lime glass. It is imperative to regulate the pH level of the concrete to 12 in order to prevent the detrimental expansion and cracking of concrete containing substantial glass particles [20].

In regard to environmental issues, Vicent et al. conducted leaching studies and determined that heavy metals do not leach out and remain in the structural network of the cementitious mix. This finding suggests that the mix with GW can be used for the production of urban pavements [131].

A body of research has identified a relationship between replacing sand with GW and an increase in the ductility of concrete. However, this assertion is not without contention, as other studies have reported contradictory trends. For example, Tamanna et al., Kim et al., Tan and Du, and Ali and Al.-Tersawy have reported results that indicate the opposite effect [132,165,177,178]. A prevailing conclusion from these studies is that the ductility outcome is dependent on the density of the waste glass used. Glass with a density lower than that of natural sand has been shown to decrease sliding performance, while glass with a density higher than that of natural sand, has been shown to increase sliding performance. While the modulus of elasticity of glass exceeds that of natural sand, an overall decrease in the modulus value is observed with an increase in the amount of waste glass in the concrete [179], which may be due to the weak bond between the glass and the cement matrix. Conversely, certain categories of GW have been found to exert a favourable influence on the durability of concrete, evidenced by a reduction in chloride penetration and porosity [32].

However, as previously mentioned, there are a multitude of challenges to overcome when using glass as a replacement for natural aggregates in concrete. These may include the chemical composition of glass, its reactivity, particle shape, contamination, sorting, variation in melting temperature according to the glass colour, costly transportation, and the possibility of ASR.

3.2.3. Influence of Coarse Aggregate-Sized Particles, Used as a Natural Coarse Aggregate Replacement, on the Properties of Concrete

The main results of the cementitious materials properties by replacing a part of the coarse aggregate with different types of GW are presented in Figure 8, Figure 9 and Figure 10 and

Table 3. The influence of different types of coarse aggregate-sized glass waste on the properties of cementitious materials.

Type of Glass	Replacement of Sand, %	Particle Size	Slump	Porosity	Density	Pb Leaching	ASR	Elasticity	Flexural Strength	References
Container glass	10, 20, 30	<20 mm	↓		↓					[179]
	25, 50, 75, 100	2.36–10 mm		↓	↓					[180]
Container glass	12,5, 25, 50, 100	10–20 mm	↓					↑↓		[181]
Bottle glass	25, 50, 75, 100	2.36–5 mm		↓↑	↓					[183]
	25, 50, 75, 100	4–16 mm			↓				↑	[131]
	10, 25, 50, 100	10–19 mm	↑							[116]
Bottle glass	16.5, 17.5	4.9–16 mm	↓		↑					[184]
Soda-lime glass	100	4.75–9.5 mm	↓	↑	↓					[185]
Windows and bottle glass	25, 50, 75, 100	<20 mm	↓							[186]
Windows and car front windshield glass	5, 10, 20	4–11.2 mm						↑↓		[187]
Car front windshield glass	25, 50, 75, 100	3–16 mm	↓							[188]
Photovoltaic solar panel glass	100	<10 mm	↓						↓	[189]
	50, 100	<8 mm			↓					[193]
CRT glass	50, 100	<20 mm	↓	↑	↑	↑				[190]
CRT glass	100	4.75–19 mm	↑			↓↑			↓	[191]
	10, 20, 30	4–10 mm	↑		↓	↑	↑	↓		[147,192]

.

The data presented show that as the replacement of the coarse natural aggregate by various GW increases, the mechanical properties of the concrete deteriorate. With a 100% replacement of coarse aggregate with GW, compressive strength decreases up to 37%, but a smaller amount of GW (up to 50%) could improve mechanical properties (Figure 8 and Figure 9). Statistical analysis, similar to the use of fine GW aggregate, shows that in most studies, the compressive strength decreased by up to 20%. The decrease in concrete strength may possibly be due to reactions associated with ASR [131] and to the irregular shape and smooth surface of GW particles, impacting adhesion to the cementitious matrix [184].

The water absorption results (Figure 10) depend on the type of GW used; bottle GW increased water absorption by up to 20%, whereas car front windshield GW decreased by 58%. The contrasting effects observed can be credited to the different physical characteristics and surface properties of the various types of GW. Bottle glass typically consists of more angular, porous, and irregularly shaped particles, which can create more gaps within the cement matrix and increase open capillary porosity. In contrast, front windshield glass is typically made up of laminated safety glass, possessing a smoother, denser surface, manufactured to resist cracking and moisture penetration. When ground and incorporated into cementitious materials, these glass particles have been shown to not only enhance the microstructural densification of the matrix but also reduce the overall porosity of the composite and improve particle packing.

It was also found that replacing part of the coarse aggregate with GW in water-pervious concrete reduced the development of ASR. This reduction was associated with the low water–binder ratio, the high content of other pozzolanic materials, and the adaptation of the porous structure [183]. It is hypothesised that the non-absorbent nature of the glass particles will facilitate the permeation of water through the concrete.

The incorporation of GW as a partial or total replacement for coarse natural aggregate in concrete mixes has been shown to adversely affect workability. This reduction in workability can be attributed to several interrelated physical and chemical properties of glass particles, differing significantly from those of conventional aggregates. The angularity and sharp edges of GW [194] appear to have a greater influence on the workability of concrete mixtures than the smoothness of its surface. As the glass content increases, the proportion of angular particles also increases, leading to heightened internal friction and reduced flowability of the mix, suggesting the water requirement is a critical factor in this context. Dilek et al. [195] attested that angular aggregates require more water under identical conditions, while Donza et al. [196] found that such aggregates also require higher doses of superplasticiser to maintain equivalent slump values compared to rounded aggregates. Excessive angularity disrupts particle cohesion, increases void content, and reduces packing efficiency. Consequently, more water is required to fill these voids, leaving less free water to facilitate flow, ultimately reducing the overall workability of the concrete mix. In addition, the lack of chemical reactivity and mechanical interlock between the glass surface and the hydrated cement compounds further affects the homogeneity and stability of the fresh concrete mix [197] and later reduces the strength of the concrete.

The thermal conductivity of concrete containing coarse waste glass exhibited a tendency to decrease with increasing GW content. This could likely be related to the significantly lower thermal conductivity of coarse GW (0.93 W/mK [198]), which is considerably lower than that of natural aggregates, such as granite (2.12–3.62 W/mK [199]).

Furthermore, the substitution of fine and coarse aggregates with GW aggregates had a deleterious effect on the pore structure of the concrete samples. The gamma-ray shielding capacity of the concrete samples demonstrated that CRT glass significantly increased the gamma-ray shielding capacity of the concrete. The linear attenuation coefficient μ was determined to be 0.154 with 100% CRT glass, which was found to be 13.8% higher than the values of the control specimen. This increase was associated with the higher density of the CRT glass [190].

In order to achieve clearer results and improve the compressive strength of concrete containing GW, future studies should focus on optimising the particle size, shape, and surface texture of GW through controlled crushing and grinding processes. Exploring surface treatments or coatings has the potential to enhance the bond between the GW and the cement matrix. The use of supplementary cementitious materials should be investigated in order to mitigate the ASR and enhance pozzolanic activity. In addition, a standardised methodology is required for the classification and characterisation of different types of GW in order to reduce variability in experimental results. Furthermore, additional research is required on mix design adjustments, such as optimal water-to-binder ratios and admixture use, to enhance workability while maintaining or increasing concrete strength and durability.

3.3. The Possibilities of GW Utilisation in Asphalt Concrete

As demonstrated in the literature, the utilisation of GW in the fabrication of asphalt pavement aggregates has been shown to be a viable option [2,200,201]. The application of GW as a natural aggregate substitute has yielded favourable outcomes, with replacement levels ranging from 20% to 100%. The highly porous pavement system (porosity 39–47%) has the potential to mitigate the effect of urban heat islands by increasing reflectivity [12]. Using GW in asphalt has been demonstrated to improve visibility at night as a consequence of its light reflecting qualities, thus promoting safety on roads due to the increase in friction coefficient. This application also contributes to the reduction of the costs of bituminous pavement and to the improvement of its dynamic performance [56]. In addition, it has been determined that fine and coarse GW can be used as mineral aggregates in asphalt concrete mixtures, according to the Marshall method. The utilisation of GW in asphalt pavements would prove to be a highly advantageous strategy to improve waste management practices [12,21].

Q. Yang et al. [202] conducted a series of experiments in which they incorporated polymer-coated glass fibres into bitumen. The findings indicated a positive effect on the durability of the bituminous composite. Furthermore, the study revealed that, compared to base bitumen, bitumen with polymer-coated glass fibre exhibited significantly higher resistance to moisture damage. Yu et al. [203] observed that the incorporation of glass from households (particle size 2.36–4.75 mm) into the asphalt mix, replacing 6%, 8% or 10% of the original volume, resulted in a substantial improvement in slip resistance and a corresponding increase in friction coefficient of 38.6%, 29.5%, and 18.2%, respectively, compared to reference sample. T. M. Phan et al. [204] determined that an elevated GW content in the asphalt mix (>5 mm) requires a higher amount of compaction energy. Specifically, incorporation of 30% GW into the modified asphalt mix resulted in a 22% increase in compaction energy compared to the standard asphalt mix. Furthermore, the incorporation of more than 20% GW in asphalt mixtures has been shown to result in a substantial reduction in resistance to rutting and moisture sensitivity. This phenomenon is presumed to occur as a consequence of smoother glass surfaces and decreased adhesion of aggregates and binder [205].

D. Jin et al. [206] conducted a leaching study on a modified asphalt mix of CRT GW, which incorporates CRT glass particles with a diameter of less than 0.075 mm. The study involved replacing 5%, 10% and 15% of the mixture. The mean leaching of lead (Pb) was determined to be 6.84 mg/L (pure CRT), 0.13 mg/L (when 5% was used), 0.41 mg/L (when 10% was used) and 0.42 mg/L (when 15% was used), respectively. As a result, the use of CRT glass powder as an asphalt binder additive has the potential to mitigate leaching issues into the environment, thus reducing the pollution associated with CRT waste. However, the use of CRT as a source of energy for the fabrication of CRTs has been documented by West et al. [207]. A test was carried out on asphalt concrete, in which crushed glass was used to substitute 15% of fine or coarse aggregate. Substituting a proportion of fine aggregate resulted in decreased values of Marshall stability and tensile strength, compared to control samples. The asphalt concrete with coarse glass demonstrated superior tensile strength properties and stronger adhesion between the asphalt binder and the glass particles [207].

In order to improve the mechanical and durability properties of asphalt mixtures that incorporate GW, future research should focus on optimising the particle size, shape, and granulometric composition of GW, distinguishing between fine and coarse fractions. Exploring surface treatments or coatings is recommended to enhance the adhesion between GW particles and the asphalt binder, addressing challenges such as reduced resistance to rutting and moisture sensitivity. Subsequent investigations should evaluate the effects of the GW content and compaction energy requirements on performance, especially at replacement levels above 20%, where deterioration has been observed. The environmental safety of GW types, such as CRT, should also be rigorously assessed through long-term leaching studies under real service conditions. The development of standardised mix design guidelines and performance-based specifications for glass-modified asphalt has the potential to optimise benefits, such as increased reflectivity, friction, and visibility, while simultaneously minimising risks associated with durability and environmental impact.

3.4. The Possibilities of Glass Waste Utilisation in Ceramic Materials

A general investigation was conducted into the use of an assortment of alternative glass raw materials, including containerised ordinary lime–sodium glass cullet, CRT waste, and TV screen glass, in conjunction with feldspar in partial clay mixtures. However, research has shown that the incorporation of fluxes results in an increase of the amorphous phase within the ceramic composite, thereby exerting a deleterious influence on its mechanical properties. Research has shown that 5% of CRT glass constitutes the optimal amount of GW to replace Na-feldspar [199,200]. This recommendation is based on the fact that a complete replacement with GW is not feasible due to the relatively low viscosity of the base glass at elevated firing temperatures. Preliminary studies indicate that the CRT glass composite initiates the sintering process at an initial temperature of 850 °C, which is lower than the standard operating temperature. At 1150 °C, the open porosity of the composite is observed to decrease significantly, indicating a transformation in its structural integrity. However, intense closed pores formation at 1200 °C results in sample deformation. Subsequent incorporation of alkaline glass, replacing Na-feldspar in porcelain stoneware bodies, gives rise to an unconventional densification behaviour, which does not culminate in complete compaction [208,209,210].

K. L. Lin et al. [211] research focused on the utilisation of thin-film transistor liquid crystal displays (TFT-LCDs) in the fabrication of glass ceramic tiles. The hardness results demonstrate that elevating the temperature at which TFT-LCD waste glass is processed improves the hardness of glass ceramics when heated to 800, 850, 900, and 950 °C to 3.0 GPa, 6.1 GPa, 12.1 GPa and 12.6 GPa, respectively. The experimental findings demonstrate a positive correlation between the degree of crystallisation of the glass ceramic samples and the increase in hardness. In [212], M. H. M. Zaid et al. conducted studies on high-purity zinc oxide (ZnO) powder (99.99%, Aldrich) and soda–lime silica (SLS) waste glass powder. The prepared glass samples were subsequently subjected to heat treatment at various temperatures (600–1000 °C) for a duration of two hours, with the objective of producing Willemite glass ceramics. The results of XRD, FESEM, and FTIR spectra demonstrated that Willemite crystals were formed from the ZnO-SLS glass precursors during the controlled crystallisation process. Subsequent experimental studies have indicated that this Willemette glass ceramic shows promise for use in the domain of optoelectronics as a prospective luminescent material. C. Xi et al. [213] investigated the preparation of glass–ceramic foams using extracted titanium tailing and GW from bottles and windows.

The study [214] established that the incorporation of 10% by weight of GW resulted in bricks that exhibited compressive strengths comparable to those of the control samples, 41–42 MPa. This process also led to enhancements in thermal performance and reductions in water absorption [214]. The authors’ [215] findings demonstrated that the rate of water absorption decreased with increasing glass content, up to a maximum of 35%, when subjected to a firing temperature of 1100 °C. At temperatures above 1100 °C, water absorption exhibited a decrease of up to 25% in glass content, subsequently increasing with a higher glass content. The bulk density and mechanical properties exhibited similar trends, with enhancements observed up to a glass content of 25%, after which a decline was observed. As the glass content and temperature increased, so did the firing shrinkage. The incorporation of glass into the tiles resulted in enhanced thermal, physical and mechanical properties, with an optimal glass content of 25% at 1150 °C. However, the addition of greater quantities of glass (greater than 25%) had a detrimental effect on these properties and the external appearance of the tiles. In contrast, the coefficient of linear thermal expansion decreased with an increase in the glass content [215]. Abdeen et al. [216] determined that when the amount of GW content in the bricks increases, and concomitantly with the firing temperature, increases in the firing shrinkage, bulk density, and compressive strength of the bricks. It is evident that as the amount of GW increases and the firing temperature increases, the apparent porosity and water absorption decrease. The particle size of GW powder was found to be a critical factor, exerting a substantial influence on the properties of fired clay bricks; as the particle size decreased, the compressive strength of the bricks increased. The findings indicate that the optimal properties of the fired bricks are achieved with a 30% GW content and a firing temperature of 1100 °C. The findings demonstrate the viability of producing bricks with compressive strengths in excess of 95 MPa and water absorption levels not exceeding 6% [216].

In the study [217], the bricks containing powder GW were incinerated in the same kiln as those without powder GW, under equivalent conditions (type of fuel, temperature, duration, etc.). The results demonstrated that the properties of the bricks were significantly improved, including their areal density, water absorption capacity, and resistance to efflorescence. The 20% increase in GW in brick samples resulted in a 14% decrease in the areal density. The incorporation of fine powder GW into the composition of the bricks resulted in a reduction in porosity, and the pores were filled by the addition of fine powder GW. The present study provided a comprehensive analysis of the use of GW as a component for the fabrication of lightweight, sustainable bricks that exhibit enhanced water absorption properties [217]. The use of GW products in the production of construction materials (particularly bricks) can be regarded as a fundamentally beneficial approach to sustainable development.

In order to optimise the use of GW in the production of ceramics, future research should focus on controlling the type, content and particle size of GW introduced into clay mixtures. Excessive GW (above 25–30%) and elevated firing temperatures (>1150 °C) have been observed to reduce mechanical strength and alter structural integrity due to excessive amorphous phase formation. It is imperative to meticulously calibrate the firing temperature, sintering kinetics, and percentage of GW to ensure optimal performance and durability. It is recommended that subsequent studies focus on the enhancement of densification and crystallisation behaviour. This can be achieved through the incorporation of nucleating agents or by integrating GW with other ceramic fluxes. In particular, the investigation of the use of treated or coated GW could assist in the management of viscosity and phase development at elevated temperatures. Furthermore, optimising the particle fineness of GW has been shown to improve compressive strength, reduce porosity, and enhance water absorption control.

4. Conclusions

• A comprehensive review of the literature and research findings reveals a clear correlation between the prevalence of consumerism and the increasing volume of GW disposed of in landfills. The recycling rate for glass varies depending on the type of glass, with an average of up to 50% for certain types. Given the extensive development of the concrete industry on a global scale, it would be advantageous to utilise various types of GW in the production of concrete or other cementitious materials, thus substituting for a portion of the cement or natural aggregates. The article also mentions the potential use of GW in the production of asphalt concrete and ceramics. Research indicates that GW has a considerable propensity to be utilised in a diverse array of mixtures, thus contributing to the improvement of sustainable waste management practices and the development of infrastructure.
• A comprehensive review of the scientific literature has revealed controversial trends in the properties of cementitious materials. It is proposed that approximately 10–20% of the cement be replaced with a dispersed fine glass cement additive. This additive acts as a pozzolanic agent, which has been shown to improve the technological and mechanical properties of cementitious materials. It has also been shown to improve the resistance of these materials to various chemical influences and to increase their durability, particularly after a longer curing time of 56–90 days. However, depending on the type of GW used, its chemical composition, crystallinity, and other factors, the properties of cementitious materials can deteriorate due to the higher air content, agglomeration of dispersed particles, reactions of harmful chemical elements, and possible leaching.
• Replacement of a portion of fine aggregate has shown that, under certain circumstances, the workability of cementitious materials can be improved because of reduced water penetration and the smooth surface of GW particles. However, in certain cases, increased friction between particles can lead to a reduction in fluidity. The mechanical properties of the material may be enhanced as a result of the finer particles’ capacity to function as a pozzolanic additive and/or microfiller. For example, when 75% of the sand was replaced with container GW, the compressive strength of fine-grained concrete increased by about 30%. The density of the material depends on the density of the glass itself, and there are instances where the density of cementitious materials may increase or decrease. The effect on the mechanical properties in this case depends on the mineral composition of the particles and adhesion to the cementitious matrix. It has been established that GW particles with a higher amorphous content have the capacity to trigger ASR. Therefore, this study must be carried out. In this instance, the results of the lead leaching tests demonstrated that Pb remained within the material’s structure and was only minimally leached.
• When coarse aggregate in concrete is replaced by coarse GW, a decrease in density and deterioration of mechanical properties are commonly observed. This is primarily due to the inadequate bonding between glass and the cementitious matrix, as well as the elevated amount of entrapped air. It has been established that workability is subject to deterioration in relation to the dimensions and configuration of the particles, in addition to the elevated levels of air incorporated. It has been demonstrated that, conversely, abrasion resistance is prone to deterioration; concurrently, however, thermal conductivity is reduced.
• The utilisation of waste glass in asphalt concrete constitutes a viable and eco-friendly approach; however, it is imperative to evaluate the amount of waste glass that can be incorporated and its inherent characteristics to ensure optimal pavement durability and safety. The size and content of the glass particles in the mix can produce a variety of benefits, including improved pavement reflectivity, increased coefficient of friction, and increased resistance to skids, which can ultimately improve road safety. Furthermore, the positive impact of bitumen and polymer-coated glass fibre has been observed on the durability and moisture resistance of asphalt. However, an increase in glass content above 20% has been found to result in a decrease in the resistance of the pavement to rutting and an increase in its susceptibility to moisture. This phenomenon can be attributed to weaker adhesion between the glass particles and the binder. However, the utilisation of certain types of waste glass, such as CRT glass, has been demonstrated to curtail the migration of hazardous substances into the environment.
• The incorporation of different GW (containerised lime–sodium glass cullet, CRT waste, TV screen glass, etc.) has a substantial impact on the physical, thermal, and mechanical properties of the ceramic products. Optimal results with a GW content of up to 25% were achieved, which decreased water absorption, improved bulk density and mechanical strength, especially when fired at 1100 °C to 1150 °C. The addition of more GW resulted in detrimental effects, including reduced compaction, increased firing shrinkage, and adverse impacts on the exterior appearance of the tiles. Furthermore, it was determined that the fineness of the glass powder, as well as the particle size of the waste material, played a crucial role in improving the compressive strength and overall properties of the clay bricks fired. The findings support the feasibility of integrating GW into the production of ceramic materials as part of sustainable construction practices, reducing waste and improving material performance. However, it is evident that there is a limit to the amount of GW that can be incorporated without compromising the quality of the final product.
• In order to fully harness the potential of GW in construction materials, future research must address the current uncertainties and technical challenges associated with its use. In cementitious materials, the inconsistent effects of GW on mechanical and durability properties highlight the need to study the influence of the chemical composition, mineralogy, and particle morphology of GW. It is imperative that research efforts are directed toward the optimisation of GW particle size, shape, and surface texture. Furthermore, exploration of surface treatments is necessary to enhance the bond with the cement matrix. The incorporation of additional cementitious materials should also be explored in order to mitigate the ASR and enhance performance. In the context of asphalt applications, improving the performance of GW-modified mixtures requires optimisation of the gradation, the implementation of surface treatments to increase the adhesion of the binder, and the refinement of compaction methodologies. It is imperative that environmental safety, particularly the leaching behaviour of e-waste glass, be rigorously assessed. The development of standardised design guidelines is imperative to ensure durability, performance, and environmental sustainability. In ceramic production, future efforts might focus on optimising the composition and quantity of GW, meticulously controlling firing conditions, and augmenting densification through the use of additives or nucleating agents. It is imperative to pay particular attention to the fineness of the particles and the phase development at elevated temperatures in order to ensure the maintenance of mechanical strength and the minimisation of defects.