Glass Waste as a Supplementary Cementitious Material in Climate Reduced Concrete – A Review

Cement is the main ingredient in concrete, and the production of cement is a costly and energy absorbing process. In addition, production of cement ominously contributes to environmental pollution, as 1 ton of cement releases about 0.9 ton of CO2 in the atmosphere. Since cement is the material which is primarily responsible for the cost and the pollution, there is a critical need to develop materials which exhibit cementitious property and could be used as a substitute of cement. Supplementary Cementitious Materials (SCM), are substances which possess cementitious properties, hence they can be used as a partial/total replacement of cement. Recently, use of recycled material, such as waste glass powder (WGP), has received augmented attention in the concrete industry. At first, waste glass was used as an aggregate replacement in concrete and it was observed that the mechanical and durability properties of the modified concrete were degraded due to the increased potential of Alkali-Silica Reaction (ASR). Later, literature studies have shown that ASR occurrence in concrete is dependent on the particle size distribution of the glass used. As the particle size decreases the ASR probability reduces. These results motivated the use of recycled glass powder (RGP) with microscopic particle size distribution as cement replacement. There are multiple benefits of using RGP as cement replacement: firstly, using a waste material would reduce the load on the landfills, secondly, the total cost would be less as recycled WGP is replacing the costly cement; and finally, the use of RGP would lead to sustainable construction as a consequence of a decrease in cement manufacturing. The present study deals with the experimental investigation on RGP as a pozzolanic cement. The Glass Powder (GP) used in this experiment was provided by the Australian company, Enviro Sand who supplied samples with two particle sizes of 75 μm and 150 μm for the purpose of this research. The main aim of this research project is to study the pozzolanic performance of GP having a particle size smaller than 150 μm. The current study involves an extensive experimental program which includes: density, compressive strength, tensile strength, pozzolanic activity, water absorption, chloride resistance, heat of hydration and drying shrinkage. Extensive concrete specimens of standard cube, cylinder and rectangular prism of standard dimensions are prepared to investigate the various material, strength and durability properties by varying the GP content. In addition, present experimental work consists of enhancing the pozzolanic performance of the GP by varying the curing conditions and modifying the mix design. In total, about 700 specimens were tested in three stages in this experimental research work The optimisations resulted in Strength Activity Index (SAI) of coarse GP which was comparable to the SAI values of much fine GP reported by the earlier published research works. Since a considerable amount of energy would be consumed in grinding the glass from coarse to fine, the grinding energy would in turn lead to increment in the cost and rise in harmful carbon di oxide emissions. The current research is significant owing to the multiple benefits mentioned in the previous paragraph, furthermore, locally, according to a recent report from Australian National Waste, Australia generates around 1.1 million tonnes of glass waste which is equivalent to about 45 kg glass per capita and approximately 44% of it is landfilled. This practice of dumping the glass waste in landfills is environmentally unsustainable, since glass is non bio-degradable in nature. The last stage mix design alteration resulted in a maximum SAI of 117%. In addition, it resulted in higher resistance to chloride ion penetration of 17% and about 23% lower heat of hydration than the control mix at 30% replacement of the coarse GP.

ASR mitigation using binary and ternary blends with waste glass powder

Reuse of waste glass as a supplementary binder and aggregate for sustainable cement-based construction materials: A review

Millions of tons of generated glass are wasted each year and being added to landfills in which glass takes one million years to decompose. Since the wasted glass contains a significant amount of silica, a main component in other supplementary cementitious materials (SCMs), this research focuses on whether waste glass powder can be used to reduce alkali-silica reaction (ASR). The glass powders were created from either a dust collection or by additional crushing, with possible blending of an existing SCM fly ash. In addition, compressive strengths of mortar mixtures with each glass powder or combined with fly ash at varying replacements of cement were also monitored. Other common SCMs were compared to the glass powders and fly ash for ASR mortar performance. The glass dust was more effective at reducing ASR than the crushed glass. With moderately reactive aggregates, all combinations of glass or fly ash at 40 percent replacement of cement were found to be acceptable for ASR resistance. However, all glass powders were also found to reduce strength of the mortar.

This study investigated the effectiveness of using recycled waste glass in portland cement concrete, both as a finely ground powder and as a crushed granular material. For the potential of glass to undergo alkali–silica reactivity (ASR) distress to be assessed, mortar bar and miniature concrete prism tests were conducted with glass as both a powder and a crushed material. Parallel studies were conducted with a crushed natural aggregate. Simultaneously, strength activity index and thermogravimetric analysis tests were conducted on cementitious mixtures to evaluate pozzolanic reactivity of glass powder when used as cement replacement material. Results showed that when glass powder (70 μm average size) was used as cement replacement material, its pozzolanic behavior (measured by thermogravimetric analysis and strength activity index) was minimal. When glass powder was used as aggregate replacement material, the combination of glass powder and ASR-prone coarse aggregates showed significantly lower expansion than did control specimens in accelerated mortar bar and miniature concrete prism tests. This result indicates the beneficial effect of using glass powder in mitigating expansion induced by ASR. The mechanism by which the fine glass powder appeared to alleviate ASR in coarse aggregates, and therefore any significant distress in test specimens, was by rapidly undergoing its own ASR, which depleted alkalinity in the vicinity of reactive coarse aggregates. ASR associated with the fine glass particles was localized, and the reaction product did not appear to generate sufficient expansion to cause global distress. Additional field studies are required to validate study findings before waste glass can be used in concrete on a large scale.

Effect of glass powder on the mechanical and drying shrinkage of glass-fiber-reinforced cementitious composites

Wastes of Glass are recognized as pozzolanic material. This study aims to investigate utilization of local glass wastes in Sudan as supplementary cementitious materials. Two glass wastes specimens having different colors are procured from a local source namely Sudanese Emirati Glass and Metal Company (SEGMAL). Then thy are ground to micro sizes producing two types of glass powders, clear white glass powder (W-GP) and colored glass powder (C-GP). The two Specimens are characterized using tests specified in American Society for Testing and Materials ASTM C311. These tests include chemical properties using X-ray Fluorescence (XRF), Loss on Ignition (LOI), Insoluble Residue (IR), also physical properties such as fineness, specific gravity, water requirement, and strength activity index (SAI). This study shows that at 7 days W-GP and C-GP produced SAI of 84% and 87% at 7-days respectively. These values are more than the 75% of SAI’s requirements of ASTM C618. Both specimens have outperformed the control OPC mix at 28 days by producing SAI of 108.68% and 123.82% for GP-W and GP-C respectively.

A review of ground waste glass as a supplementary cementitious material: A focus on alkali-silica reaction

1.1 BackgroundGlass, with its variety of forms, is a typical amorphous material that whenrecycled for numerous times, it may maintain similar chemical properties. Preliminary examination and pozzalanic activity index testing exhibited compliance with specifications and a potential for use as a supplementary cementitious material. The effects of replacement percentages that ranged from 0-20% by the total binder weight on various fresh, hardened, durability and microstructure properties were investigated. The percent of replacement 20% of glass powder (GP) by the total binder weight revealed the highest results for strength mortar. Expansion due to alkali silica reaction (ASR) reduced considerably with the increased GP content, and a level of 20% GP has exhibited the best ASR resistance. Rate of water absorption was found to reduce with replacements in the range up to 15%, indicating more impedance to capillary water permeability and expected improved durability. XRD results suggest that GP has a positive effect on the consumption of portlandite, especially in the higher percent. An average glass content of 15-20% was found optimal to produce an eco-sustainable mortar where cement is partially replaced with as much waste material as possible, and that achieves high levels of mechanical characteristics.

Waste glass (WG) is unsustainable due to its nonbiodegradable property. However, its main ingredient is silicon dioxide, which can be utilised as a supplementary cementitious material. Before reusing WG, the flexural strength (FS) and alkali–silica reaction (ASR) expansion of WG concrete are two essential properties that must be investigated. This study produced mortar containing activated glass powder using mechanical, chemical, and mechanical–chemical (combined) approaches. The results showed that mortar containing 30% WG powder using the combined method was optimal for improving the FS and mitigating the ASR expansion. The microstructure analysis was implemented to explore the activation effect on the glass powder and mortar. Moreover, a random forest (RF) model was proposed with hyperparameters tuned by beetle antennae search (BAS), aiming at predicting FS and ASR expansion precisely. A large database was established from the experimental results based on 549 samples prepared for the FS test and 183 samples produced for the expansion test. The BAS-RF model presented high correlation coefficients for both FS (0.9545) and ASR (0.9416) data sets, showing much higher accuracy than multiple linear regression and logistic regression. Finally, a sensitivity analysis was conducted to rank the variables based on importance. Apart from the curing time, the particle granularity and content of WG were demonstrated to be the most sensitive variable for FS and expansion, respectively.

Assessment of waste packaging glass bottles as supplementary cementitious materials

Basic oxygen furnace slag (BOFS) is one of the major by-products of the steelmaking industry. Its limited utilization as a construction material is primarily attributed to its chemical properties, which hinder its stability and hydraulic activity due to its high free lime (f-CaO) content. This paper explores the performance of supplementary cementitious material (SCM) synthesized with ground granulated blast furnace slag (GGBFS), freshly produced BOFS (f-BOFS), and stockpiled BOFS (s-BOFS). A total of 10 mixtures with ordinary Portland cement (OPC) replacement percentages were assessed, maintaining a total replacement of 50% OPC, incorporating 15%, 25%, and 35% of each material by weight. The laboratory experimental program encompassed material characterization, fresh and hardened properties, pozzolanic activity, and durability assessment, with comparative studies conducted for each evaluation item. Test results indicate that f- or s-BOFS, when used with GGBFS, can be a viable alternative SCM with the potential for hydraulic activities and pozzolanic reaction. The newly synthesized SCMs demonstrated improved strength development in mortar mixtures. The mixture containing [15% f-BOFS + 35% GGBFS] achieved a 28-day compressive strength of 20.6 MPa, while the [25% BOFS + 25% GGBFS] blend reached a compressive strength of 19.7 MPa. These mixtures meet Grade 80 criteria as per ASTM C989/C989M Standard Specification for Slag Cement for Use in Concrete and Mortars. A performance-based ranking system was developed by integrating results from flowability, air content, strength activity index, drying shrinkage, alkali–silica reaction, and sulfate attack. The novelty of this work lies in assessing BOFS–GGBFS blends as SCMs using this multi-criteria approach to identify the most sustainable and technically viable mixtures. Moreover, the study highlights the influence of storage-induced weathering by directly comparing the reactivity and performance of f- and s-BOFSs in ternary blends, providing new insights into optimizing the utilization of slag. Notably, regardless of f- and s-BOFSs, proportions of [15% BOFS + 35% GGBFS] demonstrated superior strength development and achieved an excellent overall ranking. These findings confirm the potential of such slag blends as suitable SCMs for mortar and concrete applications, thereby advancing the sustainability and efficiency of cementitious materials.

Supplementary cementitious materials (SCMs) have been extensively used to partly replace ordinary portland cement to reduce concrete carbon footprint and improve concrete durability. However, SCMs with varying reactivities affect the hardened properties and durability of concrete. Current prescriptive specifications to prevent alkali-silica reaction (ASR) are based only on the chemical composition of SCMs and known past performance test results. SCMs with similar chemical compositions but different reactivities will affect their efficacy to prevent ASR. In this study, SCM reactivities were correlated to their ASR prevention efficacy in mortar and concrete mixtures. SCM reactivities were determined based on the calcium hydroxide consumed by SCM at 50 ℃ in a high pH environment. The accelerated mortar bar test and the miniature concrete prism test were used to monitor the expansion and evaluate the efficacy of SCMs in terms of ASR prevention. A very highly reactive fine aggregate and several SCMs including three fly ashes, a slag, a silica fume, and a natural pozzolan with varying compositions were used. The results showed that the reactivity of SCM in the mixture and their mass fraction in the cementitious material blend was correlated well to the expansion of the mortar and concrete mixtures. The findings showed that the higher the SCM reactivity, the lower the expansion due to ASR. A possible new approach to determine the SCM efficacy in preventing ASR was discussed.

96/01931 Structural features of vitreous and glass-ceramic materials prepared from brown coal ashes

This work focuses on the preparation of a high-quality glass powder from broken household waste glass. The expected glass powder prepared from household waste must show a high amount of silicon dioxide with fine particle size. The processing technique used in this work is coarse grinding and high-speed vibratory milling under a variety of conditions to get the best quality of glass powder. The particle size and particle size distribution were examined by using DLS technique. The chemical composition was examined by EDX together with FT-IR and XRF spectroscopies. The morphology of all glass powders was investigated by SEM. The results showed that the wide range of particle size distribution occurred in all milling conditions, which approximately ranged from 1 to 10 µm, and the 4 h-milling time showed the smallest particle size of glass powder. The chemical analysis showed that the glass powder was rich in silica which contained about 67% of SiO2. After that, the various ratios of the glass powder/epoxy resin composites were formed by using the traditional casting method. The physical, mechanical and electrical properties were investigated for all composites. The results showed that the Hv value of the glass powder/epoxy resin composites exhibited a much higher value than that of pure epoxy resin. For the electrical properties, after added 1 wt% of glass powder into the matrix, the εr and R significantly increased. The Eb value of the composite prepared from waste glass powder showed no significant difference from the composite prepared from commercial SiO2. So, it can say that the waste glass powder can be used as a filler in the epoxy resin-based composite as well as the commercial SiO2 powder for the electrical insulting application.