Search Results (68)

The reuse of waste generated in various sectors has become a sustainable alternative. Advances in research highlight its potential as a secondary raw material to produce construction materials, contributing to the reduction in waste disposal while mitigating the intensive exploitation of natural resources. Tempered glass is rarely used in recycling and in the production of new materials. Therefore, this study evaluated the applicability of using it, after glass crushing, as a partial replacement for natural sand in the production of cement products. Thus, natural sand was replaced by 25% and 50% with sand resulting from glass crushing, and the mechanical properties (mechanical strength) and porosity (water absorption and void index) of the cementitious mixtures (mortars) were evaluated at 28 days, as well as their chemical properties and CO₂ emissions. Glass powder (a result of crushing glass) was added to the mixtures to maximize the use of residual materials and improve the performance of the composite. The results demonstrate gains of approximately 10% in the studied properties with the substitution of natural sand with crushed tempered glass sand, and above 24% for the addition of glass powder, i.e., the addition of 20% powder glass tends to contribute favorably to the performance of cementitious mixtures, supporting the production of more sustainable building materials and making it an appropriate strategy for the circular economy. Full article

Crushing is a critical step in the efficient utilization of quasi-brittle materials such as ores and solid wastes. During this process, materials undergo fracture, and the product particles are ejected, carrying significant kinetic energy. This study investigates typical quasi-brittle materials—concrete and quartz glass—by conducting impact crushing tests using a drop-weight apparatus under varying contact modes and input energy levels. High-speed camera was employed to capture the fracture patterns of the materials and the trajectories of the ejected particles, enabling the calculation of kinetic energy during crushing. The results indicate that under point contact loading, both kinetic energy and its proportion increase significantly with rising input energy. In contrast, under surface contact loading, the kinetic energy and its proportion exhibit minimal change as input energy increases. The average ejection velocity of particles from quartz glass specimens during crushing was 6.28 m/s, which is 2.21 times that of concrete specimens. Moreover, the average proportion of kinetic energy in quartz glass crushing was 5.049%, approximately 14.43 times greater than that in concrete. Enhancing material toughness and adopting surface contact loading help reduce both the kinetic energy and its proportion during crushing. This research contributes to minimizing kinetic energy loss and improving the efficiency of energy utilization in crushing processes. Full article

This article analyzes the properties of concrete in which up to 25% of natural fine aggregate (sand 0/4 mm fraction) was partly replaced by the crushed tempered glass waste. The granulometric composition of crushed glass waste and 0/4 mm fraction sand was unified to ensure comparable particle size distributions between the natural aggregate and the crushed tempered glass waste. The alkali silica reactivity of crushed tempered glass waste particles was evaluated. The influence of crushed tempered glass waste on the properties of fresh concrete mixture and hardened concrete was determined experimentally. Results have shown that crushed tempered glass waste is non-reactive and can be used in concrete as a partial replacement of natural fine aggregate. Partial replacement of natural fine aggregate with crushed tempered glass waste caused only an insignificant decrease in the density of the concrete mixture, while the entrained air content increased, and the slump decreased more noticeably. The addition of crushed tempered glass waste decreased the density, compressive strength, and depth of water penetration under pressure of all modified concretes. On the other hand, all modified concretes had increased water absorption and closed or total porosities, which improved their durability in terms of the number of freeze and thaw cycles. Full article

The utilization of waste glass as an aggregate in cement-based materials provides both environmental and economic benefits, but the alkali-silica reaction (ASR) caused by the reactive silica in glass aggregates is a significant challenge for its application. This study investigates the impact of different crushing methods on the ASR of glass aggregate mortar, with a focus on the effect of immersion crushing using calcium chloride (CaCl₂) solution. Glass aggregates were prepared using conventional crushing, water immersion crushing, and CaCl₂ immersion crushing methods. The ASR expansion and compressive strength of the mortar were evaluated through accelerated ASR tests, compressive strength testing, and microstructural analysis using SEM/EDS and mercury intrusion porosimetry (MIP). Results show that immersion crushing significantly mitigated ASR expansion and the associated loss in compressive strength. The CaCl₂ immersion method yielded the most pronounced effect. Compared with conventional crushing, it reduced the ASR expansion by approximately 45% and improved the compressive strengths by approximately 20%. Microstructural analysis revealed that the CaCl₂ treatment led to a higher Ca/Si ratio in the ASR gel, which reduced the gel’s water-absorbing swelling ability and consequently suppressed ASR-induced expansion. Additionally, the CaCl₂ immersion crushing method resulted in the smallest changes in porosity and pore size distribution. These findings provide a theoretical basis for the safe use of waste glass in cement-based materials and contribute to the promotion of resource recycling in the construction industry. Full article

The increasing generation of construction and demolition waste (CDW) and the overexploitation of natural aggregates (NA) have necessitated sustainable solutions for recycled aggregate concrete (RAC). This study proposes an innovative inorganic–organic combined modification method using water glass (WG) and sodium methyl silicate (SMS) to enhance the performance of recycled coarse aggregate (RCA) and RAC. A comprehensive experimental program was conducted, including crushing value tests, capillary water absorption, compressive and splitting tensile strength analysis, nanoindentation and Fourier transform infrared spectroscopy (FTIR). The results demonstrated that the combined treatment of 40% WG and 10% SMS significantly improved the RCA properties, reducing water absorption by up to 46.47% and increasing the compressive strength of the RAC by 34.8%. Through mechanistic analysis, it was found that after treatment with SMS solution, a hydrophobic film formed on the surface of the RCA, thereby preventing the transmission of moisture. The interface transition zone between the RCA and the new cement mortar was enhanced, consequently improving the mechanical properties of the RAC. This study contributes to improving the properties of recycled aggregate and recycled aggregate concrete, and to the understanding of the mechanism of combined modification. Full article

This study examines the effectiveness of pervious concrete pavements as a sustainable and cost-effective stormwater management technique, particularly by incorporating locally sourced recycled materials into their design. It evaluates the stormwater treatment potential of three pervious concrete pavement types incorporating recycled plastic, glass, and crushed concrete aggregates, with six design variations produced using 25% and 50% replacements of coarse aggregates from these materials. The key properties of pervious concrete, namely compressive strength, porosity, unit weight, and infiltration, and key water quality indicators, namely pH, electrical conductivity (EC), total suspended solids (TSS), colour, turbidity, chemical oxygen demand (COD), nitrate (NO₃⁻), and orthophosphate (PO₄³⁻), were analysed. Results indicated an overall improvement in the quality of the stormwater runoff passed through all pervious concrete pavements irrespective of composition. Notable reductions in turbidity, TSS, colour, COD, PO₄³⁻, and NO₃⁻ underscored the effectiveness of pervious concrete containing waste materials in the treatment of stormwater runoff. Pervious concrete pavements with 25% recycled concrete exhibited optimal performance in reducing TSS, COD, and PO₄³⁻ levels, while the 50% recycled concrete variant excelled in diminishing turbidity. However, the study found that the use of recycled materials in pervious concrete pavements affects properties like compressive strength and infiltration rate differently. While incorporating 25% and 50% recycled concrete aggregates did not significantly reduce compressive strength, the effectiveness of stormwater treatment varied based on the mix design and type of recycled material used. Thus, this study highlights the potential of utilizing recycled waste materials in pervious concrete pavements for sustainable stormwater management. Full article

Rapid population growth and accelerating urbanization are intensifying the demand for construction materials, particularly concrete, which is predominantly produced with Portland cement and natural aggregates. This reliance imposes substantial environmental burdens through resource depletion and greenhouse gas emissions. Within the framework of sustainable construction, recycled aggregates and industrial by-products such as fly ash, slags, crushed glass, and other secondary raw materials have emerged as viable substitutes in concrete production. At the same time, three-dimensional concrete printing (3DCP) offers opportunities to optimize material use and minimize waste, yet it requires tailored mix designs with controlled rheological and mechanical performance. This review synthesizes current knowledge on the use of recycled construction and demolition waste, industrial by-products, and geopolymers in concrete mixtures for 3D printing applications. Particular attention is given to pozzolanic activity, particle size effects, mechanical strength, rheology, thermal conductivity, and fire resistance of recycled-based composites. The environmental assessment is considered through life-cycle analysis (LCA), emphasizing carbon footprint reduction strategies enabled by recycled constituents and low-clinker formulations. The analysis demonstrates that recycled-based 3D printable concretes can maintain or enhance structural performance while mix-level (cradle-to-gate, A1–A3) LCAs of printable mixes report CO₂ reductions typically in the range of ~20–50% depending on clinker substitution and recycled constituents—with up to ~48% for fine recycled aggregates when accompanied by cement reduction and up to ~62% for mixes with recycled concrete powder, subject to preserved printability. This work highlights both opportunities and challenges, outlining pathways for advancing durable, energy-efficient, and environmentally responsible 3D-printed construction materials. Full article

The United States of America could build 20,000 bases for the Statue of Liberty every year using its construction and demolition waste, and 456 bases using waste glass from jars and bottles. However, some sectors of the population still face a shortage of affordable housing. The challenges of disposing of such large amounts of waste and solving the housing shortage could be addressed together if these materials, considered part of a closed-loop system, were integrated into new building blocks. This research studies compressed earth blocks that incorporate soils and gravels excavated in situ, river sand, crushed concrete from demolition waste, and recycled glass sand. To stabilize the blocks, cement is used at 5, 10, and 15% (by weight). The properties studied include the following: density, apparent porosity, initial water absorption, simple compression, modulus of elasticity, and thermal conductivity. Optical image analysis proved to be a tool for predicting the values of these properties as the stabilizer changed. To assist in decision making regarding the best overall performance of the total 12 mix designs, a ranking system is proposed. The best blocks, which incorporate the otherwise waste materials, exhibited simple compression values up to 7.3 MPa, initial water absorption of 8 g/(cm² × min^0.5) and thermal conductivity of 0.684 W/m·K. Full article

The aviation industry is under increasing pressure to reduce its environmental impact while maintaining safety and performance standards. One promising area for improvement lies in the use of sustainable materials in airport infrastructure. One of the issues preventing uptake of emerging sustainable technologies is the lack of guidance relating to the opportunities, potential benefits, associated risks and an implementation plan specific to airport pavements. This research reviewed opportunities to incorporate waste materials into rigid airport pavements, focusing on concrete base slabs. Commonly used supplementary cementitious materials (SCMs), such as fly ash and ground granulated blast furnace slag (GGBFS) were considered, as well as recycled aggregates, including recycled concrete aggregate (RCA), recycled crushed glass (RCG), and blast furnace slag (BFS). Environmental Product Declarations (EPDs) were also used to quantify the potential for environmental benefit associated with various concrete mixtures, with findings showing 23% to 50% reductions in embodied carbon are possible for selected theoretical concrete mixtures that incorporate waste materials. With considered evaluation and structured implementation, the integration of waste materials into rigid airport pavements offers a practical and effective route to improve environmental outcomes in aviation infrastructure. It was concluded that a Triple Bottom Line (TBL) framework—assessing financial, environmental, and social factors—guides material selection and can support sustainable decision-making, as does performance-based specifications that enable sustainable technologies to be incorporated into airport pavement. The study also proposed a consequence-based implementation hierarchy to facilitate responsible adoption of waste materials in airside pavements. The outcomes of this review will assist airport managers and pavement designers to implement practical changes to achieve more sustainable rigid airport pavements in the future. Full article

The increasing demand for sustainable construction materials has driven research into low-carbon geopolymers that mitigate both cement-related emissions and plastic and glass waste accumulation. This study explores the development of geopolymer concrete incorporating fly ash (FA), slag (S), and FA + S blends, with 10% recycled crushed glass (RCG) and recycled plastic waste (RPW) as partial coarse aggregate replacements. Compressive strength testing revealed that FA + S-based geopolymers (25FA + S) with 100% ordinary Portland cement (OPC) replacement achieved a 7-day strength of 24.6 MPa, representing a 98% improvement over control specimens. Slag-based geopolymers demonstrated water absorption properties comparable to OPC, indicating enhanced durability. Microstructural analyses using SEM, XRD, and EDS confirmed the formation of a dense aluminosilicate matrix, with slag promoting FA reactivity and reinforcing interfacial transition zone (ITZ). These effects contributed to superior mechanical performance and water resistance. Despite minor shrinkage-induced cracking, full OPC replacement with S or FA + S geopolymers outperformed control specimens, consistently exceeding the target strength of 15 MPa required for low-impact, single-story housing applications within seven days. These findings underscore the potential of geopolymer systems for rapid and sustainable construction, offering an effective solution for reducing carbon footprints and repurposing industrial waste. Full article

The construction industry faces a growing challenge in managing waste materials, making the development of sustainable alternatives critical. This study investigates the preparation of geopolymers using construction and demolition waste materials, such as cement, brick, and glass waste. Specifically, crushed glass was used to produce sodium silicate, a key source of silicate ions and alkali necessary in geopolymerization processes. The performance of this in-house activator was compared to that of the commercial counterpart. Seven geopolymer formulations were prepared and characterized using SEM-EDX, ATR-FTIR, and XRD techniques. Chemical resistance against harsh environments was assessed through a 7-day immersion in water, hydrochloric acid (pH ~ 1), and sodium hydroxide (pH ~ 13) solutions. The samples were then dried and weighed to determine mass loss, revealing the promising resistance of specific formulations. Similarly, Portland cement specimens of the same dimensions as the geopolymer ones were prepared, tested, and compared to the geopolymers. Our study emphasizes the potential of transforming waste materials into high-performance, resistant geopolymers for construction materials. By optimizing waste-derived geopolymers, we may achieve significant environmental benefits through waste recycling and contribute to advancing sustainable construction technology. Full article

The article provides a brief overview of technologies and methods for processing dispersed metallic waste generated during ferroalloy production, including high-carbon ferrochrome (HCFeCr). It is noted that the most cost-effective and rational method for reusing metallic dust is briquetting. Considering the development of briquetting technologies, as well as the latest equipment and binder materials involved in this process, aspiration dust from ferrochrome crushing can be fully utilized in metallurgical recycling. To verify this assumption, laboratory studies were conducted using polymer-based binders and liquid glass as a baseline option. The methodology of briquetting using both laboratory and industrial presses is described, along with an assessment of the mechanical properties of the briquettes. The studies indicate that the introduction of an inert filler (gas-cleaning dust) into the metallic dust composition improves the briquetting ability of the mixture by enhancing adhesion between metal particles and the binder. The obtained industrial briquette samples exhibit high mechanical strength, ensuring their further use in metallurgical processing. The study concludes that semi-dry briquetting using hydraulic vibropresses is a promising approach for the utilization of dispersed ferroalloy waste. Full article

In response to the need for sustainable soil stabilization alternatives, this study explores the use of waste materials and biopolymers to improve the mechanical behavior of clay from Cartagena, Colombia. Crushed limestone waste (CLW), ground glass powder (GG), recycled gypsum (GY), xanthan gum (XG), and the combination of XG with polypropylene fibers (XG–PPF) were used as stabilizing agents. Samples were compacted at different dry densities and cured for 28 days. Unconfined compressive strength (UCS) and ultrasonic pulse velocity (UPV) tests were conducted to assess the strength and stiffness of the treated mixtures. Results were normalized using the porosity/binder index ($\mathrm{\eta }/B_{iv}$), leading to predictive equations with high determination coefficients (R² = 0.94 for UCS and R² = 0.96 for stiffness). However, XG-treated mixtures exhibited distinct behavior that prevented their inclusion in a unified predictive model, as the fitted exponent x in the porosity/binder index ($\mathrm{\eta }/B_{iv}^x$) differed markedly from the others. While an exponent of 0.28 was suitable for blends with mineral binders, the optimal x values for XG and XG–PPF mixtures were significantly lower at 0.02 and 0.03, respectively, reflecting their unique gel-like and fiber-reinforced characteristics. The analysis of variance (ANOVA) identified cement content and compaction density as the most influential factors, while some interactions involving the residues were not statistically significant, despite aligning with experimental trends. The findings support the technical viability of using sustainable additives to enhance soil properties with reduced environmental impact. Full article

The global production of waste glass and the challenges associated with its reuse and disposal highlight the urgent need for effective alternatives to prevent the accumulation of landfill. Researchers have already explored the potential of replacing naturally quarried aggregates with waste glass to minimize its accumulation in landfills and the depletion of natural resources. Previous studies have reported that recycled crushed glass (RCG) has a high silica content, angularity, shear strength, and durability, properties which make it a promising material for construction applications. However, there are limited assessments in the existing literature of the performance of RCG as a construction material for transportation infrastructure. This paper reviews the physical, chemical, and geotechnical properties of RCG reported in the literature and compares their findings; it also discusses the existing studies related to its suitability for field applications. This paper also highlights the environmental impact and health concerns of replacing natural aggregates with waste glass by emphasizing its role in sustainable development and the circular economy in the construction of transportation infrastructure. Full article

The present investigation introduces a novel approach, using As-Zn-Fe mining tailings (MT) and recycled bottle glass (cullet) to enable the manufacturing of a new glass for ornamental articles, with characteristics similar to those of soda–lime–silicate glass (SLS), and at the same time, immobilizing potentially toxic elements (PTEs) from mining tailings, which cause environmental pollution with severe risks to human health. The glass used was obtained from transparent glass bottles collected from urban waste, which were later washed to remove impurities and then crushed until they reached No. 70 mesh (212 μm) level; in the case of mining tailings, the sample used comes from the ore benefit process, with 96.8% of particles below the No. 50 mesh level (300 μm). Six mixtures were made by varying the composition of the mining tailings and glass, K₂CO₃ and H₃BO₃ as fluxes were also used in constant proportion. The mixtures were melted at 1370 °C, and later, the glass samples were cast on a steel plate at room temperature. The characteristics of the glasses were studied using thermal analysis (TA), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and scanning electron microscopy (SEM). Likewise, their chemical resistance in acid and basic media and density were evaluated. The results unequivocally demonstrate the feasibility of manufacturing glasses with a light green color, the increase in the content of mining tailings increased the apparent T_g from 625 to 831 °C. Glasses with 17 and 21.3% MT presented lower density values due to a better-polymerized glass structure, attributed to the increase in SiO₂ and Al₂O₃ and the decrease in alkaline oxides, which allowed for the retention of PTEs in their structure. Full article