Waste Glass Research Articles

Evaluation of high-volume fly-ash cementitious binders incorporating nanosilica as eco-friendly sustainable concrete repair materials

Nowadays, the use of environmentally friendly, long-lasting building materials with minimal energy and carbon dioxide emissions are highly recommended. Some of these materials can be made from industrial and agricultural wastes. By replacing ordinary Portland cement (OPC) with large volume of fly ash waste (FA), environmental issues associated with landfill disposal and cement manufacture can be mitigated. Nonetheless, using a high amount of FA (up to 50 %) to replace cement resulted in poor strength performance, particularly during early age. This experimental study created an increased strength cement mortar containing a high volume of FA (60 %) and bottle glass waste nanoparticles (BGWNPs). In this experiment BGWNPs were prepared and 2, 4, 6, 8 and 10 vol% of them were used as a replacement of OPC-FA binder. According to the results, by adding 0–6 % of BGWNPs to a high-volume FA matrix considerably increased the bond strength (from 12.5 % to 39.1 %). On the other hand, the findings revealed that the addition of nanoparticles (up to 6 %) caused a modest reduction in strength values. Other engineering and microstructure properties showed a similar pattern. The matrix with 6 % BGWNPs displayed the best performance when compared to other levels. The results also showed that replacing OPC by high volume FA incorporating BGWNPs significantly improved the durability of proposed mortar, such as reduction in drying shrinkage and increased acid attack and abrasion resistance. Related to the environment benefits, the proposed mortars contributed in a reduction of carbon dioxide emission, energy consumption and cost of binder by 61.9 %, 54.3 % and 50.6 % compared to OPC, respectively. To conclude, the use of BGWNPs make it possible to produce high volumes of FA-based cement mortars with acceptable mechanical and durable properties for concrete repair applications in the construction industry. Additionally, sustainability can be attained by lowering pollution, recycling waste, and finding solutions to landfill problems.

The performance of waste glass aggregate concrete GFRP-steel double-skin tubular columns under axial compression: Experimental study

In an attempt to alleviate the problem of growing waste glass and fully utilize the excellent material properties of fiber-reinforced polymer (FRP), a novel composite structure, waste glass aggregate concrete glass fiber reinforced polymer (GFRP)-steel double-skin tubular column (WGAC-DSTC), was proposed based on the FRP-concrete-steel double-skin tubular column (DSTC). In the present research, eight WGAC-DSTCs and four waste glass aggregate concrete-filled GFRP tubular columns (WGAC-CFFTs) were investigated to explore their mechanical performance under axial compression. Effects of diverse replacement ratio of waste glass aggregate, GFRP tube thickness, and hollow ratio of column on the mechanical performance of twelve columns were investigated. Meanwhile, this research analyzed and discussed the failure characteristics of columns, load-displacement relationship, ductility coefficient, stiffness coefficient, parameter analysis, ultimate bearing capacity, load-strain relationship and constraint factor. Besides, predicted formulae for estimating the ultimate bearing capacity of WGAC-CFFTs and WGAC-DSTCs were proposed. The research results indicated that (1) Failure mode of the WGAC-DSTCs displayed axial compression failure or shear failure and failure mode of WGAC-CFFTs exhibited mainly axial compression failure; (2) WGAC-DSTCs with 10 % replacement ratio of waste glass aggregate and hollow ratio of 0.4 indicated an increase in the ultimate bearing capacity by 17.24 % and 45.78 %, respectively, as the GFRP tube thickness increased from 1.5 mm to 2 mm and 3 mm. As the column's hollow ratio enhanced from 0.27 to 0.68, the column's ultimate bearing capacity significantly decreased by 7.08 %-60.55 %. The ultimate bearing capacity of WGAC-CFFTs showed a trend of first increasing by 8.33 %-9.41 % but then decreasing by 1.52 % when the replacement ratio of waste glass aggregate rose from 0 % to 30 %; (3) WGAC could replace natural aggregate concrete in traditional DSTC and the bearing capacity could be guaranteed. Besides, it's recommended to utilize 20 % replacement ratio of waste glass aggregate for the WGAC-DSTC whose ultimate bearing capacity enhanced by 15.17 % and possessing optimal mechanical performance; (4) The results calculated utilizing predicted formulae matched well with results of experiment. The application of waste glass aggregate concrete in DSTC can contribute to economic growth and environmental protection and meet the concept of sustainable development.

Effect of MICP-recycled GFRP fiber on the self-repairing properties of concrete

The recycling of waste glass fiber-reinforced polymer (GFRP) holds paramount importance in realizing sustainability goals. This study aims to enhance the efficacy of fiber-reinforced self-healing concrete by employing recycled GFRP (rGFRP) fibers as carriers for Microbiologically Induced Calcite Precipitation (MICP). Preparations involved the development of pretreatment of rGFRP using microbial mineralization. Examination encompassed the assessment of interactions between microorganisms and fibers, microstructural characterization of self-healing specimens, and the strength of repaired specimens. This was conducted through the quantification of CaCO3 precipitation, strength tests, scanning electron microscopy (SEM), X-ray computed topography (CT) analysis, and mercury intrusion porosimetry (MIP). The results revealed that mineralized rGFRP fibers had little impact on the flexural and compressive strength of the reinforced mortar, while increased the tensile strength by up to 34.1 %. The mineralized rGFRP fiber-reinforced mortar achieved a repair rate of 84.5 % for cracks within 0.3 mm after 28 days of water curing. Comparatively, the mineralized rGFRP fiber bacterial mortar exhibited higher water absorption than its non-mineralized counterpart. Using untreated rGFRP fibers for self-healing can reduce the porosity and water absorption of the mortar to some extent, while adding mineralized rGFRP fibers for self-healing increased the crack area repair rate and also increased the porosity of the mortar. Therefore, using untreated rGFRP fibers as a carrier for microorganisms to repair mortar may present a more favorable choice. The results of this study will contribute to further improvement in the application of fiber-reinforced self-healing concrete in the engineering field.

Developing hybrid C-sections from waste and recycled composite materials

This paper investigates the performance of hybrid composites made from mixed waste plastics (wMP), recycled carbon fibre (rCF), and waste glass fibre (wGF). Two lay-up configurations with varying wGF and rCF contents were considered: one with approximately 7 vol% rCF (25 vol% wGF) and another with approximately 15 vol% rCF (9.4 vol% wGF). The tensile, compressive, and flexural performance of standard coupon specimens for both configurations were assessed, revealing that specimens with increased rCF content exhibited superior performance. Additionally, three hybrid C-sections, containing 15 vol% rCF, were thermoformed and subjected to axial compression. All three C-sections failed due to bearing failure, accompanied by some interlaminar delamination and material crushing at the loading ends. Their weight-specific load capacity surpassed that of similar sections published in the literature, such as ultra-thin-walled steel C-sections, by almost 95 %. A finite element model (FEM) of the C-section was developed and was able to predict reasonably well the stress versus strain response. These findings demonstrate that waste and recycled composite materials could serve as sustainable alternatives to ultra-thin-walled steel C-sections and other conventional materials commonly used in construction.

Use of Lignin, Waste Tire Rubber, and Waste Glass for Soil Stabilization

The complex interactions between soil and additives such as lignin, glass powder, and rubber tires were investigated using principles of material and soil mechanics. Previous research has mainly focused on individual additives in clay soils. In contrast, this study investigates soil improvement with two different types of waste materials simultaneously. The improvement of soil properties by hybrid waste materials was evaluated using several laboratory tests, including the standard Proctor test, the unconfined compressive strength test, the California Bearing Ratio (CBR) test, and cyclic triaxial tests. The aim of this research is to identify key parameters for the design and construction of road pavements and to demonstrate that improving the subgrade with hybrid waste materials contributes significantly to the sustainability of road construction. The mechanical and physical properties were evaluated in detail to determine the optimal mixtures. The results show that the most effective mixture for the combination of waste glass powder and rubber tires contains 20% glass powder and 3% rubber tires, based on the dry weight of the soil. For the combination of waste glass powder and lignin, the optimum mixture consists of 15% glass powder and 15% lignin, based on the dry weight of the soil. These results provide valuable insights into the sustainable use of waste materials for soil stabilization in road construction projects.

Influence of waste glass on the gamma-ray shielding performance of concrete

In this work, the local low-cost materials from Nigeria were companied together to produce a lead-free concrete that can be used in shielding the ionizing γ-rays. This work investigated the impacts of partially replacing coarse aggregates (crushed granite) with a crushed waste glass on the chemical, physical, and radiation shielding characteristics. The developed concretes’ density was measured experimentally, and the fabricated concretes’ elemental chemical composition was determined utilizing a Thermo-Scientific X-ray fluorescence connected to an ARL-QUANT’X-EDXRF-Analyzer. The increase in the waste glass/granite (WG/G) substitution ratio between 0 and 17.6 % decreases the density of the produced concrete from 2.4 g/cm3 to 2.33 g/cm3. On the other hand, the absorption per unit mass (MAC) of the produced concretes increased by raising the WG/G ratio, where there was a 0.217–0.247 cm2/g increase in the MAC at 0.081 MeV, by raising the WG/G ratio between 0 and 17.6 %. Simultaneously, the study shows that the radiation protection efficiency (RPE) at 2.506 MeV for a 10 cm thickness of the fabricated concrete reaches 53.49, 61.14, 54.98, and 55.29 % for concretes with WG/G content of 0.0, 5.3, 11.1, and 17.6 % with the same order, respectively. Therefore, the thicker thicknesses of the developed concretes can offer high shielding capacity to be applied in radiation protection applications.

Investigation of Conditions for Using Mass-Produced Waste Glass as Sustainable Fine Aggregate for Mortar

To address the environmental issues arising from the growing scarcity of natural fine aggregates (NFA) and landfilling of waste glass, research is being conducted globally to utilize waste glass as a sustainable fine aggregate. However, contradictory results have been obtained regarding the effect of the type of waste glass and the physical properties of waste glass fine aggregate (GFA) on concrete, making it challenging to promote the use of GFA in concrete. Therefore, to promote the use of GFA in concrete, it is necessary to examine it under field conditions, such as mass-production processes or real-scale concrete applications. This study introduced a mass-production process for GFA, and the effect of mass-produced GFA on mortar was evaluated. The fine aggregate properties (particle aspect ratio, crushing rate, and solubility) of the GFA and the effects of color, content, and particle size on the mortar properties (compressive strength, flexural strength, and ASR expansion behavior) were analyzed, along with the results reported in previous studies. Consequently, the high aspect ratio and microcracks in the particles of mass-produced GFA led to an increase in the strength reduction and ASR expansion of the mortar. These effects appear to be particularly severe for transparent GFA. Overall, this study proposed the content of GFA within 20% or the replacement of fine particles (< 500 μm) in NFA as a condition for sustainable fine aggregate.

Mixing design and performance of porous asphalt mixtures containing solid waste

The process of urbanization generates substantial amounts of solid waste materials, including glass, red brick, concrete, and ceramic tile. Effective treatment methods for these waste materials are currently lacking, resulting in significant land wastage and environmental pollution. Utilizing these waste materials in the construction of asphalt pavements presents a viable solution for their high-quality and large-scale utilization. In this study, the properties of commonly produced urban solid waste materials, including glass, red brick, concrete, and ceramic tile, were investigated for their suitability as limestone porous asphalt mixtures. The physical and chemical properties of the coarse aggregate were examined using four groups of preliminary tests, including leakage analysis, scattering, rutting, and freeze-thaw splitting tests. The results revealed that the apparent relative density varied for different particle sizes within the range of 2.36–4.75 mm, 4.75–9.5 mm, 9.5–16 mm, and 13.2–16 mm. However, the dynamic stability of the glass specimen was only 740 times/mm, which falls significantly below the technical requirement of 1500 times/mm. Additionally, the high-temperature stability of the glass specimen was deemed unsatisfactory. The red brick test piece exhibited inadequate water stability due to its high-water absorption rate. Therefore, reducing the amount of waste glass and minimizing the incorporation of waste red brick are recommended. The findings of this study contribute to the expansion of application methods and techniques for urban solid waste, improving the utilization rate of solid waste resources. Furthermore, the study sheds light on the changes in the performance of solid waste aggregates mixed with porous asphalt mixtures, providing valuable insights for road engineering endeavors.

SYNTHESES AND CHARACTERISTICS OF CALCIUM-BASED GEOPOLYMER FROM SOLAR-CELL PANEL-GLASS WASTE BY HYDROTHERMAL METHOD

A calcium-based geopolymer was synthesized using a blend of recycled glass powder from solar panels (PV glass waste), limestone, and a sodium silicate solution, which underwent hydrothermal autoclaving at 180 °C for varying durations. This material is regarded as environmentally friendly and has garnered research attention worldwide. In this investigation, limestone served as the calcium source, while recycled glass from solar panels provided the SiO2 necessary for producing calcium-based geopolymer materials. Currently, solar-panel waste poses a significant environmental challenge that requires attention. The objective of this research was to develop a sustainable and high-performance calcium-based geopolymer using waste materials, specifically recycled glass from solar panels and limestone. The study aimed to evaluate the effects of hydrothermal autoclaving on the compressive strength, volume weight, porosity, and water absorption of the synthesized geopolymer, as well as to understand the microstructural transformations involved. The results revealed a remarkable 430 % increase in the compressive strength of the specimens following hydrothermal autoclaving for 24 to 96 hours compared to the unautoclaved samples. Concurrently, the volumetric weight had a substantial rise from 1.54 % to 2.31 g/cm3, with corresponding decreases in the porosity and water absorption from 38.1 % to 16.9 % and 10.26 % to 5.08 %, respectively. An X-ray diffraction (XRD) analysis of the mineral composition and a scanning electron microscope (SEM) examination of the microstructure demonstrated a transformation of all samples from an amorphous gel structure to needle- or spike-shaped fibrous, and then sheet-like CSH structures. These new structures exhibited dimensions of less than 10 µm in length, less than 2 µm in width, and less than 400 nm in thickness. The resulting CSH products constitute calcium silicate hydrate minerals, characteristic of calcium silicate materials, which are synthetic products arising from chemical reactions among SiO2, CaO, and H2O under hydrothermal conditions. This study underscores the potential of using recycled materials to produced high-strength geopolymers, offering a promising solution to the environmental challenge of solar-panel waste.

Compositional effects on the growth of diopside crystals in the simulated high‐level waste glass

Compositional effects on the growth of diopside crystals in the simulated high‐level waste glass

Fabrication of a Concrete Roof Tile by Geopolymerization of Red Clay with Container Glass Wastes

We report the production of concrete roof tiles using a red clay-based geopolymer binder with container glass waste and river sand as a concrete filler. Clear and colored container glass wastes were separately ground to powder and blended with low-grade red clay to achieve a SiO2/Al2O3 ratio of approximately 7.0. The powder blends were converted to geopastes with a solid-to-alkali solution ratio of approximately 0.8 using a 12-molar alkali activator solution containing a mixture of potassium hydroxide and sodium hydroxide. Rheological analysis showed that the geopaste binders with transparent and colored glass powders exhibited high shear thinning behavior. A higher viscosity was observed for the geopaste with colored glass powder due to the presence of colorants. Fine and coarse particles of river sand were prepared and mixed with different ratios of geopaste binder to river sand of 1:2.0, 1:2.5, and 1:3.0, respectively. All geopaste and river sand formulations were poured into acetate molds and heated in a metal chamber at 80 °C for 24 h, then aged at room temperature for 14 d. The highest flexural strength of 2.33 MPa was obtained from the formulation with a 1:2 ratio of geopaste with transparent glass powder and fine sand. The measured strength corresponded to an apparent porosity of 6.30% and a water absorption of 4.50%. The bulk density was approximately 1.16 g/cm³, which is classified as a lightweight material. A prototype geopolymer concrete roof tile was successfully produced with a sorption coefficient of approximately 0.170 mm/min1/2. This measured sorption coefficient and the physical properties indicate that the produced roof tile is a potential building material.

Application of KF/waste glass catalyst in the synthesis of fatty acid esters under pressurized conditions without glycerol generation

In this study, the efficiency of applying the KF/waste glass catalyst was tested in the transesterification of crambe oil under pressurized conditions for the synthesis of esters and glycerol carbonate (GLC). For this, a miscella pressurized extraction was used. The influence of temperature on different residence times was evaluated, and to verify the effect of the catalyst on the process, non-catalytic reactions were conducted. In reactions without the use of catalyst, a temperature of 250 °C was required to obtain >90 % esters yield. In the catalytic reactions, the operating conditions were reduced to 225 °C, to obtain ∼96 % esters yield, also providing the synthesis of a greater quantity of GLC, and a glycerol-free sample. The wet modification of powdered glass waste with KF results in the K2SiF6, NaF, CaF2, and KCaF3 phases. The laser-induced breakdown spectroscopy analyses showed the presence of fluorinated compounds in the catalyst. Furthermore, calcium and sodium ions from the glass waste matrix support were the source for the crystalization of K2SiF6/CaF2/KCaF3 and NaF phases, respectively. The catalyst showed a good catalytic activity, promoting high ester and GLC formation at 225 °C, 10 min and 10 MPa, remaining with good performance even after 8h of reaction, but it is important to mention that the stability of the catalyst needs to be improved due to the leaching of K to Ca.

Study on fresh and hardened state properties of eco-friendly foamed concrete incorporating waste soda-lime glass

Improper waste management is causing global environmental problems. Waste glass may have adverse impacts on the ecosystem. While a substantial amount of soda-lime glass bottle (SGB) undergoes recycling to create new glass items, a significant volume still ends up in landfills. Therefore, the aim of this study was to explore the potential use of SGB in foamed concrete (FC) production as an aggregate replacement. SGB was substituted for sand in different weight fractions, ranging from 5 to 50%. The fresh state, mechanical, thermal, pore structure, and transport properties were examined. The findings showed a significant enhancement in the FC’s mechanical properties when SGB replaced 20% of sand. The compressive, flexural, and splitting tensile strengths exhibited a rise of up to 17.7, 39.4, and 43.8%, respectively. The findings also demonstrated that the addition of SGB improved the thermal conductivity, sorptivity, water absorption, and porosity. The scanning electron microscopy analysis indicated that the inclusion of 20% SGB caused a substantial decrease in void diameter and enhanced its uniformity. A comparison was made between the experimental data and predictions of the mechanical properties using various models of international standards, such as IS 456, ACI 318, NZS-3101, EC-02, AS 3600, and CEB-FIB, along with several references in the literature. The findings implied a strong correlation between the strength properties. The outcomes of this research offer valuable insights into both the possible advantages and constraints of using SGB in FC. Furthermore, this extensive laboratory investigation may serve as a guideline for future study and aid in the advancement of greener and more environmentally friendly FC alternatives.

French nuclear glass synthesis: Focus on liquid waste dissolution kinetics

In France, high-level nuclear wastes are confined in glass using a calcination-vitrification process. The waste can also be vitrified by liquid feeding, which imply to add directly the liquid waste. In this study, we focus on nuclear waste vitrification process by direct liquid feeding in order to decipher the dissolution kinetics of the waste in the molten glass. We propose an experimental and analytical protocol to study the dissolution in the solid glass frit of the liquid waste dried beforehand during the glass melting process. This methodology allows to: i) identify the intermediate reaction phases which formed and dissolved during the process; ii) characterizes the evolution of waste element concentrations in the dried waste as a function of time and temperature on glass obtained after cooling; iii) define kinetic parameters relative to the process of intermediate reaction phases dissolution in the molten glass. The three main intermediate reaction phases formed and dissolved in function of temperature are Ca-REE (Rare Earth Elements)- silicate, Ce- oxide and Zr- oxide. At each temperature step (800 to 1200 °C) the evolution of REE (La, Ce, Nd and Pr) and Zr concentrations in the glass samples obtained after cooling shows a fast increase followed by a stabilization in time, which reflects the fast dissolution of the dried waste in the molten glass, i.e. the fast dissolution of intermediate reaction phases. The molten glass is completely homogeneous at classical synthesis temperature (1200 °C). A parameterization methodology of element concentration evolution as a function of time and temperature is proposed here in order to define the kinetic parameters corresponding to the dried waste dissolution (i.e. concentration at a given time t, maximal concentration at a given temperature, characteristic time and activation energy). The results show that the activation related to the formation and dissolution processes of the intermediate reaction phases, i.e. whether they constitute intermediate compounds formed in temperature by the interaction between the dried waste and the glass frit, and the phases formed without reacting with the glass frit, directly in the dried waste during heat treatment.

Flexural and fracture characterization of UHPGC notched beam with various glass sand replacement ratios and steel fiber contents

The preparation process of quartz sand (QS) can cause serious environmental pollution, which is particularly important to find a new replacement material for QS in cement-based construction materials. In this study, an economical and environmentally friendly ultra-high performance glass sand concrete (UHPGC) was prepared by partially replacing QS in conventional ultra-high performance concrete (UHPC) with glass sand (GS) ground from waste glass. The effects of material composition characteristics including water-binder ratio (W/B), GS replacement ratio, and steel fiber content on the flexural and fracture characteristics of UHPGC notched beams were investigated based on response surface method (RSM) and acoustic emission (AE) monitoring. The results indicate that the GS replacement rate presents almost no effect on the tensile strength and flexural toughness of the specimens while reducing the water-binder ratio or increasing the steel fiber content can significantly improve the flexural tensile strength of UHPGC notched beams. UHPGC notched beams show the best performance when the W/B is 0.17, the steel fiber content is 3 %, and the GS replacement rate is 50 %. By analyzing and comparing the AE parameters and fracture modes, the discrepancies in flexural and fracture properties of UHPGC notched beams with variable material composition characteristics can be elucidated. Among them, the low water-binder ratio or high steel fiber content has a significant effect on the fracture characteristics and fracture process of the specimens, while the GS replacement rate exhibits negligible effect.

Sustainable repurpose of end-of-life fiber reinforced polymer composites: A new circular pedestrian bridge concept

In response to global challenges in resource supply, many industries are adopting the principles of the Circular Economy (CE) to improve their resource acquisition strategies. This paper introduces an innovative approach to address the environmental impact of waste Glass Fiber Reinforced-Polymer (GFRP) pipes and panels by repurposing them to manufacture structural components for new bicycle and pedestrian bridges. The study covers the entire process, including conceptualization, analysis, design, and testing of a deck system, with a focus on the manufacturing process for a 7-m-long prototype bridge. The study shows promising results in the concept of a sandwich structure utilizing discarded GFRP pipes and panels, which has the flexibility to account for variabilities in dimensions of incoming products while still meeting mechanical requirements. The LCA analysis shows that the transportation of materials is the governing contributing factor. It was concluded that further development of this concept should be accompanied by a business model that considers the importance of the contributions from the whole value chain.

Properties of Adhesive Mortars Using Waste Glass.

This study investigates the use of waste glass as an active aggregate in glass polymers based on water glass, aiming to enhance the sustainability of construction materials by utilizing recyclable waste. Methodologically, the research employs a combination of water glass as a binder with waste glass, analyzing their chemical interaction and the resulting mechanical properties. The primary findings reveal that the inclusion of finely ground waste glass not only promotes the polycondensation and hardening processes of water glass but also significantly influences the adhesive and cohesive strengths of the developed glass polymers. After 7 days of hardening, the tensile strength of these materials exceeds that of standard concrete with values reaching up to 4.11 MPa, indicating strong adhesion capabilities that could pull out fragments of the concrete substrate. Conclusively, the study underscores the potential of waste glass in improving the structural and economic efficiencies of building materials, contributing to a reduction in landfill waste and offering a promising avenue for the innovative use of recyclable materials in construction.

Development of eco-friendly engineered cementitious composites (ECC) with both waste glass powder and aggregate: A comprehensive investigation

This study investigated the micro-macro properties of engineered cementitious composites (ECC) with both waste glass powder (WGP) and waste glass aggregate (WGA) as substitutes for binder and silica sand, aiming to achieve sustainable ECC materials and recycle waste glass in a high-value approach. The results indicate that a high volume of WGP used as a replacement for cement leads to a loose microstructure in ECC, whereas ECC prepared with 100 % WGA replacing silica sand exhibit a better microstructure compared to the reference ECC. Replacing cement with a high volume of WGP reduces the compressive and flexural strengths, but replacing silica sand with WGA increases the compressive and flexural strengths of ECC. Under tensile loading, both WGP replacing binders and WGA replacing silica sand enhance the strain capacity of ECC at substitution rates not exceeding 25 %. As the substitution rate increases, replacing 50 % of cement with WGP reduces the strain capacity and ultimate tensile strength of ECC by 18 % and 32.5 %, respectively. Nevertheless, substituting WGA for silica sand can enhance the strain capacity of ECC. Substituting WGP for the binders increases the transport properties and water-permeable porosity of blended ECC, while the replacement of silica sand with a moderate dosage of WGA reduces the water transport properties and water-permeable porosity. The simultaneous substitution of binder and silica sand with WGP and WGA, respectively, enables the production of sustainable ECC with desirable micro-macro properties. The complete replacement of silica sand and fly ash with WGA and WGP, respectively, is feasible, whereas the substitution of cement with a high-volume WGP should be limited.

Evaluation of TPS 3R and Waste Bank Management in Sungai Penuh City

Sungai Penuh City has 16 units of TPS 3R and 1 unit of waste bank that are not operating optimally. The evaluation to determine the condition of TPS 3R and waste bank and the potential reduction obtained if they are operated again. The research began by collecting data on generation of solid waste, composition, and recycling possibilities for household waste. Sampling of waste generation based on SNI 19-3964-1994 in 8 sub-districts in Sungai Penuh City for 8 consecutive days with the household generation of solid waste outcome of 0.328 kg/person/day or 2.789 l/person/day. The composition of household waste in Sungai Penuh City includes 57.74% food waste, 14.38% plastic waste, 11.62% paper waste, 5.19% yard waste, 4.89% other waste, 2.79% glass waste, 2.16% fabric waste and 1.24% metal. Sungai Penuh City has the capacity to recycle household solid waste is 68.90%. TPS 3R and waste bank was evaluated based on the Technical Guidelines for TPS 3R of The Ministry of Public Works and Housing in 2023 and the Regulation by the Minister of Environment and Forestry Number 14 of 2021. The evaluation results show that 3 units of TPS 3R are in the medium category, 4 units of TPS 3R are in the less category and 9 units of TPS 3R are in the bad category. Meanwhile, waste bank is in the bad category. The potential for waste reduction by TPS 3R and waste bank if operated optimally is 23.26% of the total waste generated in Sungai Penuh City.

Embodied carbon saving potential of using recycled materials as cement substitute in Singapore’s buildings

Material production and construction activities are key contributors to global carbon footprints, necessitating sustainable alternatives. This study aims to investigate the potential of integrating recycled materials as Supplementary Cementitious Materials (SCMs) in concrete production to mitigate the substantial carbon emissions of Singapore’s building and construction sector. The research focuses on Ground Granulated Blast-furnace Slag (GGBFS), waste glass powder, and calcined marine clay as alternative SCMs, aiming to reduce environmental impact and waste disposal emissions in Singapore. Employing a cradle-to-gate Life Cycle Assessment (LCA) methodology for 1 m3 of concrete with different grades, this study quantifies embodied carbon savings and assesses the feasibility of substituting these SCMs in concrete. The results reveal that substituting Ordinary Portland Cement (OPC) with GGBFS in concrete offers the most significant reduction, up to 56%, in 1 m3 of concrete. In contrast, the use of calcined marine clay and glass powder in concrete results in reductions of up to 21% and 16%, respectively. Two case studies were used to exemplify the impact of using SCM concrete at the project scale. Results indicate that up to 31% of the total embodied carbon could be saved in the building. Additionally, scenario analysis suggests that the total emissions from cementitious materials in Singapore could decrease by 20% through the incorporation of locally recycled marine clay and glass powder. This reduction could potentially reach 56% if the GGBFS supply is not constrained. To further enhance sustainability in Singapore’s construction sector, the study proposes sourcing GGBFS from neighboring countries to minimize transportation emissions and localizing the production and usage of calcined marine clay and glass powder. These measures can improve material circularity and significantly contribute to achieving carbon reduction targets.