Design and properties of ternary alkali-activated binder based on blast furnace slag, recycled powder and waste glass powder.

Ternary alkali-activated binder was prepared by blast furnace slag (GGBS), recycled powder (RP) and waste glass powder (WGP) using simplex centroid design method. By measuring the fluidity, setting time, drying shrinkage and mechanical property of specimen, the complementary effect of GGBS, RP and WGP was discussed. The reaction mechanism and microstructure were explored by X-ray diffraction and scanning electron microscopy. The results reveal that the addition of RP could significantly reduce the fluidity and setting time of paste, while WGP can obviously improve the rheological property and play a retarding role. The workability of paste can be effectively regulated by mixing RP and WGP together. Whether added alone or in combination, RP and WGP can effectively improve the shrinkage performance. In the ternary system, GGBS can be rapidly activated and form a skeleton structure. The fine RP particles can play a good role in filling the structure, and the pozzolanic reaction of WGP gradually occurs, which makes the microstructure more compact. The incorporation of GGBS, RP and WGP can promote the growth of hydration products, improve the density of microstructure, and form a certain complementary effect.

The reuse of waste glass for enhancement of heavy metals immobilization during the introduction of galvanized sludge in brick manufacturing.

The mixing of galvanized sludge in fired clay brick manufacturing has been regarded as an alternative approach for the consumption of galvanized sludge. Decreasing the surface area and porosity of fired brick definitely lowers the risk of heavy metal release. In this study, a novel method is proposed to reduce the surface area and porosity of bricks and promote heavy metal immobilization by adding waste glass. The introduction of waste glass enhanced the physical and mechanical performances of fired clay bricks and resulted in an increase in bulk density and compressive strength and a decrease in water absorption. Microstructure analysis showed that the texture of the bricks turned from porous to smooth and homogeneous due to the introduction of waste glass. Porosity analysis showed that surface area and pore volume of fired brick were substantially reduced. When the added waste glass amount exceeded 15 wt%, the heavy metal concentrations that leached from bricks containing 10 wt% galvanized sludge fired at 950 °C met the regulatory requirement. These results demonstrate that waste glass can be reused to enhance the stabilization/solidification of heavy metals, during the mixing of hazardous waste in bricks and ceramics manufacturing process.

Multi-Criteria Optimization of Cost-Effective and Environmentally Friendly Reactive Powder Concrete Incorporating Waste Glass and Micro Calcium Carbonate.

In pursuit of developing an eco-friendly and cost-effective reactive powder concrete (RPC), we utilized a multi-objective optimization technique. This approach pivoted on the incorporation of byproducts, with a spotlight on ground glass powder (GP) as a pivotal supplementary cementitious material (SCM). Our goal was twofold: engineering cost-efficient concrete while maintaining environmental integrity. The derived RPC showcased robust mechanical strength and impressive workability. Rigorous evaluations, containing attributes like compressive strength, resistance to chloride ion penetration, ultrasonic pulse speed, and drying shrinkage, highlighted its merits. Notably, the optimized RPC, despite an insignificant decrease in compressive strength at 90 days compared to its traditional counterpart, maintained steady strength augmentation over time. The refinement process culminated in a notable 29% reduction in ordinary Portland cement (OPC) usage and a significant 64% decrease in silica fume (SF), with the optimized mix composition being 590 for cement, 100 for SF, 335 for GP, and 257 kg/m3 for calcium carbonate. Additionally, the optimized RPC stood out due to the enhanced rheological behavior, influenced by the lubricative properties of calcium carbonate and the water conservation features of the glass powder. The reactive properties of SF, combined with GP, brought distinct performance variations, most evident at 28 days. Yet, both mixtures exhibited superior resistance to chloride, deeming them ideal for rigorous settings like coastal regions. Significantly, the RPC iteration, enriched with selective mineral admixtures, displayed a reduced tendency for drying-induced shrinkage, mitigating potential crack emergence.

Recycling Local Waste Glass Bottles into Cement Paste: Effect on Hydration, Microstructure, and CO2 Emission.

Large amounts of waste glass are generated along with the manufacturing of glass products, causing detrimental effects on the environment. Through crushing and ball-milling, waste glass powder (WGP) can be acquired from glass bottles and has been suggested in cementitious systems due to its potential pozzolanic activity. To better understand the impact of WGP on cementitious composites, experimental tests of rheology, heat of hydration, and strength development were conducted on cement pastes with and without WGP. Results show that the rheological performance of cement paste is improved when WGP with particles passing through 80 µm sieves is incorporated. The retarding effect and pozzolanic reaction were observed through X-ray diffraction patterns and thermo-gravimetric parameter analyses. A calcium hydroxide (CH) content calculation further confirms the secondary reactivity of WGP in cement pastes. Compared with the samples without WGP, the normalized CH content of binder per unit mass containing 35% WGP decreased by 21.01%, 24.94%, and 27.41% at the ages of 1, 28, and 90 days, respectively, which contributes to late-age strength development of pastes. At the same time, the hydration per unit of cement was increased by 21.53%, 15.48%, and 11.68%, which improved the cement efficiency. In addition, WGP particles provide nuclei for hydration products, facilitating the subsequent growth of C-S-H and strength development in late ages. Based on value engineering analysis, WGP was found to reduce the impact of Portland cement on the environment by 34.9% in terms of carbon dioxide emissions, indicating a bright prospect for WGP in the cement industry.

Effect of air pollution-controlled residue of a sewage sludge incinerator on the drying shrinkage and the pore structure of alkali-activated materials.

Recycling air pollution-controlled residues (APCR) generated from sewage sludge incinerators can be used for waste management, but the leaching of potentially toxic heavy metals from APCR poses environmental and human health issues. The present paper describes a procedure using APCR to produce alkali-activated materials and thereby realize their disposal. The effect of APCR on the compressive strength and drying shrinkage of the alkali-activated slag/glass powder was investigated. The pore structure characteristics were analyzed for clarifying its relationship with drying shrinkage. The results indicated that the drying shrinkage of the alkali-activated material was related to the mesopore volume. The drying shrinkage was slightly increased after the incorporation of the 10 % APCR, which was likely attributed to the high volume of mesopores compared to the 20 % APCR that lowered the drying shrinkage and compressive strength. This decrease in drying shrinkage was due to the recrystallization of sodium sulfate in the pore solution that can act as expansive agents and aggregates. The growth stress of the crystalline sodium sulfate within the matrix can offset the tension stress caused by the water loss. In addition, leaching studies using the SW-846 Method 1311 showed that recycling APCR into the alkali-activated system did not present a toxicity leaching risk or release unacceptable concentrations of heavy metals. The incorporation of waste APCR and waste glass can make AAMs a very promising and safe environmental technology.

Evaluating the effectiveness of waste glass powder for the compressive strength improvement of cement mortar using experimental and machine learning methods.

This study utilized both experimental testing and machine learning (ML) strategies to assess the effectiveness of waste glass powder (WGP) on the compressive strength (CS) of cement mortar. The cement-to-sand ratio was kept 1:1 with a water-to-cement ratio of 0.25. The superplasticizer content was 4% by cement mass, and the proportion of silica fume was 15%, 20%, and 25% by cement mass in three different mixes. WGP was added to cement mortar at replacement contents from 0 to 15% for sand and cement with a 2.5% increment. Initially, using an experimental method, the CS of WGP-based cement mortar at the age of 28 days was calculated. The obtained data were then used to forecast the CS using ML techniques. For CS estimation, two ML approaches, namely decision tree and AdaBoost, were applied. The ML model's performance was assessed by calculating the coefficient of determination (R2), performing statistical tests and k-fold validation, and assessing the variance between the experimental and model outcomes. The use of WGP enhanced the CS of cement mortar, as noted from the experimental results. Maximum CS was attained by substituting 10% WGP for cement and 15% WGP for sand. The findings of the modeling techniques demonstrated that the decision tree had a reasonable level of accuracy, while the AdaBoost predicted the CS of WGP-based cement mortar with a higher level of accuracy. Utilizing ML approaches will benefit the construction industry by providing efficient and economic approaches for assessing the properties of materials.

Experimental Study on Long-Term Mechanical Properties and Durability of Waste Glass Added to OPC Concrete.

This study aims to achieve the sustainable utilization of waste glass resources through an investigation into the influence of three types of admixtures, namely waste glass powder (WGP) (G), waste glass powder-slag (G-S), and waste glass powder-fly ash (G-F), on the mechanical properties and durability performance of waste glass concrete. The experimental results demonstrate that the exclusive use of WGP as an admixture led to the relatively poor early compressive strength of the concrete, which decreased with an increase in dosage. However, at medium to long curing ages, the strength of the waste glass concrete could equal or even surpass that of ordinary concrete. When dual admixtures were employed, the G-S group exhibited higher compressive strength compared to the G-F group. Specifically, within the G-S group, a glass powder dosage of 15% yielded higher compressive strength, and after 180 days, the dual admixture groups exhibited greater strength than ordinary concrete (G0); the compressive strength of the tG1S1 group was 44.57 MPa, and that of the G0 group was 40.07 MPa. The chloride ion diffusion coefficient showed a varying trend with an increase in WGP dosage, initially decreasing and then increasing. The concrete's resistance to erosion was maximized when the glass powder dosage reached 30%. As the WGP dosage increased, the overall frost resistance decreased. For a total dosage of 30%, the optimal glass powder dosage in both G-S and G-F groups was found to be 15%.

Evaluating the Strength and Impact of Raw Ingredients of Cement Mortar Incorporating Waste Glass Powder Using Machine Learning and SHapley Additive ExPlanations (SHAP) Methods.

This research employed machine learning (ML) and SHapley Additive ExPlanations (SHAP) methods to assess the strength and impact of raw ingredients of cement mortar (CM) incorporated with waste glass powder (WGP). The data required for this study were generated using an experimental approach. Two ML methods were employed, i.e., gradient boosting and random forest, for compressive strength (CS) and flexural strength (FS) estimation. The performance of ML approaches was evaluated by comparing the coefficient of determination (R2), statistical checks, k-fold assessment, and analyzing the variation between experimental and estimated strength. The results of the ML-based modeling approaches revealed that the gradient boosting model had a good degree of precision, but the random forest model predicted the strength of the WGP-based CM with a greater degree of precision for CS and FS prediction. The SHAP analysis revealed that fine aggregate was a critical raw material, with a stronger negative link to the strength of the material, whereas WGP and cement had a greater positive effect on the strength of CM. Utilizing such approaches will benefit the building sector by supporting the progress of rapid and inexpensive approaches for identifying material attributes and the impact of raw ingredients.

Influence of Waste Glass Powder Addition on the Microstructure and Mechanical Properties of Autoclaved Building Materials.

Lime quartz samples in which ground quartz sand was gradually substituted with waste glass powder (GP) were obtained under hydrothermal conditions to determine the influence of GP addition on the microstructure (observed by SEM), phase composition (analyzed by XRD), and compressive strength of autoclaved building materials. An additional series containing analytical grade NaOH and no GP was formed to evaluate the effect of sodium ions on tobermorite formation and its impact on the mechanical properties of the samples. GP addition hindered the formation of tobermorite during autoclaving. Instead, a higher amount of an amorphous and semi-crystalline C-S-H phase formed, leading to the densification of the composite matrix. Nevertheless, tobermorite-like structures were found during both XRD and SEM analyses, proving that the presence of small amounts of Al3+ ions allowed, to an extent, for the stabilization of the phase despite the high sodium content. The compressive strength values indicate that the presence of alkali in the system and the resulting formation of additional portions of C-S-H have a beneficial influence on the mechanical properties of autoclaved composites. However, the effect fades with increasing glass powder content which, together with a slight expansion of the samples, suggests that at high sand substitution levels, an alkali-silica reaction takes place.

Waste Glass Powder Reusability in High-Performance Concrete: Leaching Behavior and Ecotoxicity.

This paper deals with the possibility of using different types of waste glass powder in high-performance concrete (HPC) mixtures as a fine fraction replacement. Subsequently, both fractions are used in this research in concrete as a substitute for fine sand and silica flour. To use waste glass in a basic building material such as concrete, it is necessary to verify the basic chemical properties of the selected waste materials. Apart from the basic chemical properties, its environmental impact also appears to be an essential property of waste materials in general. Therefore, the research is mainly focused on the leaching and ecotoxicity experiments on high-performance concrete. HPC mixtures are designed based on the results of the analyzed chemical properties and previous research performed by our research team. Ecotoxicity of these concretes is then verified using Czech standards to evaluate. The results showed a positive impact on the ecotoxic properties of waste glass when used in concrete. A new ecotoxicity classification of waste materials and concrete mixes containing waste materials is proposed as a result of this research and summarized in the conclusion of this paper.

Possibilities of disposing silica fume and waste glass powder, which are environmental wastes, by using as a substitute for Portland cement.

In this study, the possibilities of disposal of environmental waste, silica fume, and waste glass powder as substitutes in the mortar samples in Portland cement were investigated. For this purpose, Portland cement (CEM I), silica fume (SF), waste glass powder (WGP), CEN standard sand, and water were used in mortar production. Additive cements were obtained by using the SF, WGP, and SFWGP substitution methods in Portland cement at the rates of 10, 20, 30, and 40%. The flexural strength, compressive strength, radiation permeability (determination of linear absorption coefficient), high temperature, and alkali-silica reaction (ASR) effect on SF, WGP, and SFWGP were examined and compared with the control PC 42.5R samples. Mortar samples of 40 × 40 × 160 mm size were obtained with the grouts/mortars produced, and the samples were exposed to five temperature effects, namely, 20, 150, 300, 700, and 1000 ° C. Samples kept at 20 ° C are accepted as baseline. A total of 429 samples were studied, including the cooling process in the air (spontaneously in the laboratory, 20 ° C ± 2). After the samples achieved room temperature, flexural and compressive strength tests were carried out at 28 and 90 days. Test results demonstrate that SF, WGP, and SFWGP, which are environmental wastes, can be disposed both as a pozzolanic additive material both alone and together in cement mortars, can be utilized in buildings with high fire hazard, and the sample with the highest linear absorption coefficient is the sample obtained with SFWGP, and also, the expansion values ​​that occur in SF and WGP are less than the control sample.

Incorporation of Waste Glass as an Activator in Class-C Fly Ash/GGBS Based Alkali Activated Material.

In this study, an alkaline activator was synthesized by dissolving waste glass powder (WGP) in NaOH-4M solution to explore its effects on the formation of alkali-activated material (AAM) generated by Class-C fly ash (FA) and ground granulated blast furnace slag (GGBS). The compressive strength, flexure strength, porosity and water absorption were measured, and X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray (SEM-EDX) were used to study the crystalline phases, hydration mechanism and microstructure of the resulting composites. Results indicated that the composition of alkali solutions and the ratios of FA/GGBS were significant in enhancing the properties of the obtained AAM. As the amount of dissolved WGP increased in alkaline solution, the silicon concentration increased, causing the accelerated reactivity of FA/GGBS to develop Ca-based hydrate gel as the main reaction product in the system, thereby increasing the strength and lowering the porosity. Further increase in WGP dissolution led to strength loss and increased porosity, which were believed to be due to the excessive water demand of FA/GGBS composites to achieve optimum mixing consistency. Increasing the GGBS proportion in a composite appeared to improve the strength and lower the porosity owing to the reactivity of GGBS being higher than that of FA, which contributed to develop C-S-H-type hydration.

Effective Utilization of Waste Glass as Cementitious Powder and Construction Sand in Mortar.

The purpose of this study is to investigate the availability of waste glass as alternative materials in sustainable constructions. Collected waste glass was ground into waste glass powder (WGP) with similar particle size distribution as Portland cement (PC) and waste glass sand (WGS) with similar grade as sand. The compressive strength was investigated through the Taguchi test to evaluate the effect of different parameters on WGP-blended mortar, which include WG-replacement rate (G/B, 0, 10%, 20%, 30%), water/binder ratio (w/b, 0.35. 0.40, 0.50, 0.60), cementitious material dosage (Cpaste, 420, 450, 480, 500 kg/m3), and color of powder (green (G) and colorless (C)). The alkali-silica reaction (ASR) expansion risk of WGS-blended mortar was assessed. The experimental results indicated that WGP after 0.5 h grinding could be used as substituted cement in mortar and help to release potential ASR expansion. The replacement rate played a dominant role on strength at both the early or long-term age. The water/binder ratio of 0.35 was beneficial to the compressive strength at three days and 0.50 was better for strength at 60 and 90 days. An optimal value of cementitious material dosage (450 Kg/m3) exited in view of its strength, while the effect of the color of WG was minor. WGS could be graded as standard construction sand and no ASR expansion risk was found even for 100% replacement of regular sand in mortar. Through the comprehensive reuse of waste glass, this study could provide basic knowledge and a concept for the sustainable development of building materials.

Performance of Nano-Silica Modified Self-Compacting Glass Mortar at Normal and Elevated Temperatures.

This research aims to combine the effects of nanosilica and glass powder on the properties of self-compacting mortar at normal and at higher temperatures. The fine aggregate was replaced by waste glass powder at various percentage levels of 10%, 20%, 30%, 40% and 50%. The mechanical properties of self-compacting glass mortar (SGCM) were studied at elevated temperatures of 200, 400, 600 and 800 °C. Furthermore the effect of sudden and gradual cooling technique on the residual strength of glass mortar was also investigated In order to enhance the behavior of SCGM the nanosilica of 3% by weight of cement was added. From the results it was obtained that the glass powder replacement effectively contributed towards the thermal performance while the addition of nanosilica enhanced the mechanical performance. The enhanced physical properties were obtained mainly at the glass transition temperature thus showing the active participation of glass powders during high temperatures. Moreover the gradually cooled specimens exhibited improved strength characteristics than the suddenly cooled specimens.

Combined use of waste concrete and glass as a replacement for mortar raw materials.

The construction industry offers one of the most attractive options in the use of recycled materials due to its large consumption of raw materials and high construction work rates. Also, the debris from construction and demolition is responsible for a high participation rate in the generation of waste, with concrete being a major contributor in this category. Waste glass powder, on the other hand, is a material that offers an excellent alternative to replace cement due to its well-known pozzolanic properties. Hence, the combined behaviour of fine recycled concrete aggregates and glass powder of different particle sizes in mortars has been studied. Different mixtures are analyzed with the aim of minimizing losses in mechanical properties and durability in an attempt to maximize the amount of replaced materials. Due to the delayed pozzolanic reaction by the glass powder, the samples present highly satisfactory results at 90 days of curing, with values of their properties close to those of the control mortar. The results are encouraging when glass powder with a smaller particle size is used due to its filler effect combined with its pozzolanic activity, making it possible to replace up to 20% of glass powder with a maximum size of 38 µm, with up to 30% of fine recycled concrete aggregates. Finally, the evaluation of greenhouse gases showed that the simultaneous incorporation of both types of waste reduces the CO2 emissions associated with concrete by up to 19%.

High Sulfate Attack Resistance of Reinforced Concrete Flumes Containing Liquid Crystal Display (LCD) Waste Glass Powder.

To prevent chemical erosion of concrete and improve chemical resistance, reinforced concrete flumes were manufactured, conforming to the Korean Industrial Standards (KS). Two different sizes of liquid crystal display (LCD) waste glass powder (LWGP) particles were used (i.e., 5 and 12 µm) with two substitution types with cement in concrete (i.e., 10% and 20%). Changes in compressive strength, pore structure, weight, volume, and strength of the concrete flumes after immersion in two sulfate solutions (i.e., Na2SO4 and MgSO4) for 84 and 182 days were measured for sulfate attack resistance. The applicability of the LWGP concrete flume with a 0.5 mm crack width was also evaluated based on the bending strength results. The LWGP5, which has a smaller particle size among LWGPs, filled the smaller pores, thereby reducing the porosity and contributing to the compressive strength gain. Higher volume and weight change ratios for all specimens immersed in MgSO4 solution were found than those immersed in Na2SO4 solution under identical conditions. Flexural loads of all the LWGP concrete flumes with 0.05 mm crack widths were greater than 48.5 kN, as required by the KS code; however, these flexural loads were lower than those of ordinary Portland cement. The applicability was also validated via a flexural test complying with KS.