Production Of Sustainable Concrete Research Articles

Sustainable Concrete Production: Utilizing Cow Dung Ash and Corn Stalk Ash as Eco-Friendly Alternatives

This study aims to determine whether it is feasible to replace conventional materials used in manufacturing concrete with waste materials, namely cow dung ash and corn stalk ash. This study proposes to assess the possibility of using these agricultural by-products to improve the sustainability of concrete while simultaneously tackling the environmental issues related to the manufacture of conventional concrete. The research aims to assess the mechanical qualities, optimize the mix proportions, and examine the ecological implications of using these substitute materials. This research aims to mitigate environmental challenges like carbon dioxide emissions, resource depletion, and the accumulation of agricultural waste by combining agricultural waste and lowering dependency on traditional cement. The study investigates the use of cow dung ash (CDA) and corn stalk ash (CSA) as alternatives for conventional Portland cement (OPC) in mortar mixes at varying quantities, ranging from 5% to 25% CDA and 2.5% to 10% CSA. Chemical composition reveals that CDA and CSA predominantly comprise O, Mg, Al, Si, P, K, and Ca. The workability, hardened characteristics, and microstructure of CDA and CSA were assessed. Increasing CDA and CSA percentages reduced mortar workability; nevertheless, replacing 8% to 10% CDA and 7.5% CSA maintained compressive, tensile, and flexural strengths comparable to control mixes. However, more significant CDA and CSA proportions resulted in lower mortar strength. For example, 10% CDA-enriched mortar had a compressive strength of 31.77 N/mm2, a tensile strength of 3.42 N/mm2, and a flexural strength of 3.61 N/mm2, whereas 7.5% CSA-enriched mortar had a compressive strength of 28.4 N/mm2, a tensile strength of 3.04 N/mm2, and a flexural strength of 3.7 N/mm2. According to the findings, CDA and CSA can replace OPC by up to 10% and 7.5% in mortar manufacturing, making cementitious material alternatives viable. Doi: 10.28991/CEJ-SP2024-010-02 Full Text: PDF

Utilizing bio-based and industrial waste aggregates to improve mechanical properties and thermal insulation in lightweight foamed macro polypropylene fibre-reinforced concrete

This research intends to examine the potential of incorporating waste materials in place of coarse aggregates to augment the mechanical characteristics and thermal insulation of lightweight foamed concrete (LWFC), along with the inclusion of polypropylene (PP) fibres. The PP fibre exhibits excellent tensile strength and enhancement on thermal insulation properties of cementitious materials. In this study, eco-friendly bio-based oil palm shell (OPS) and robust solid polyurethane (SPU) aggregates derived from industrial waste were utilized as substitutes for conventional aggregates. Additionally, silica fume was partially incorporated as supplementary cementitious materials. The addition of PP fibre impacted the workability of the LWFC with the inverted slump value decreased by 1.7 %–17.5 %. The inclusion of PP fibre proportion increased from 0 % to 0.5 % revealed a positive result in mechanical properties and thermal insulation performance. The OPSSPU/0.5 showed the significantly increment of 40.4 % compressive strength, 102.9 % of splitting tensile strength, and 70.8 % flexural strength, respectively. The optimum result was obtained in the OPSSPU/0.5 mixture, which exhibited 3.74 MPa residual compressive strength. Furthermore, utilizing PP fibres brought about a significant reduction in thermal conductivity in the environmentally sustainable LWFC, leading to improvements ranging from 0.2 % to 16.3 % when compared to the control composition. Thus, these findings are essential for encouraging the adoption of such practices in the construction industry and contributing to the reduction of environmental impacts associated with sustainable concrete production.

Predicting the impact of adding metakaolin on the splitting strength of concrete using ensemble ML classification and symbolic regression techniques –a comparative study

The mechanical characteristics of concrete are crucial factors in structural design standards especially in concrete technology. Employing reliable prediction models for concrete’s mechanical properties can reduce the number of necessary laboratory trials, checks and experiments to obtain valuable representative design data, thus saving both time and resources. Metakaolin (MK) is commonly utilized as a supplementary replacement for Portland cement in sustainable concrete production due to its technical and environmental benefits towards net-zero goals of the United Nations Sustainable Development Goals (UNSDGs). In this research work, 204 data entries from concrete mixes produced with the addition of metakaolin (MK) were collected and analyzed using eight (8) ensemble machine learning tools and one (1) symbolic regression technique. The application of multiple machine learning protocols such as the ensemble group and the symbolic regression techniques have not been presented in any previous research work on the modeling of splitting tensile strength of MK mixed concrete. The data was partitioned and applied according to standard conditions. Lastly, some selected performance evaluation indices were used to test the models’ accuracy in predicting the splitting strength (Fsp) of the studied MK-mixed concrete. At the end, results show that the k-nearest neighbor (KNN) outperformed the other techniques in the ensemble group with the following indices; SSE of 4% and 1%, MAE of 0.1 and 0.2 MPa, MSE of 0, RMSE of 0.1 and 0.2 MPa, Error of 0.04% and 0.04%, Accuracy of 0.96 and 0.96 and R2 of 0.98 and 0.98 for the training and validation models, respectively. This is followed closely by the support vector machine (SVM) with the following indices; SSE of 7% and 3%, MAE of 0.2 and 0.2 MPa, MSE of 0.0 and 0.1 MPa, RMSE of 0.2 and 0.3 MPa, Error of 0.05% and 0.06%, Accuracy of 0.95 and 0.94, and R2 of 0.96 and 0.95, for the training and validation models, respectively. The third model in the superiority rank is the CN2 with the following performance indices; SSE of 15% and 4%, MAE of 0.2 and 0.2 MPa, MSE of 0.1 and 0.1 MPa, RMSE of 0.3 and 0.3 MPa, Error of 0.08% and 0.07%, Accuracy of 0.92 and 0.93 and R2 of 0.92 and 0.93, for the training and validation models, respectively. These models outperformed the models utilized on the MK-mixed concrete found in the literature, therefore are the better decisive modes for the prediction of the splitting strength (Fsp) of the studied MK-mixed concrete with 204 mix data entries. Conversely, the NB and SGD produced unacceptable model performances, however, this is true for the modeled database collected for the MK-mixed Fsp. The RSM model also produced superior performance with an accuracy of over 95% and adequate precision of more than 27. Overall, the KNN, SVM, CN2 and RSM have shown to possess the potential to predict the MK-mixed Fsp for structural concrete designs and production.

Efficiency of self-compacting concrete made with variable sustainable cementitious materials: A TOPSIS algorithm approach

The use of supplementary cementitious materials as a partial replacement for cement is taking the lead in the concrete production industry. Being known as by-products from various manufacturing properties, concrete produced with such materials is considered a sustainable alternative to normal concrete. Three different by-product materials have been investigated in this study for the production of sustainable self-compacting concrete (SCC), namely, ground granulated blast furnace slag (GGBS), fly ash (FA), and silica fume (SF). Compressive strength, production cost, and global warming potential (GWP) were the main testing parameters for the mixes' performances. Multi-criteria decision-making algorithm was implemented using the TOPSIS model to investigate the ultimate performance of those SCC mixes considering all tested parameters simultaneously. Results showed the best SCC performance can be attained when using about 60 % of GGBS as a partial replacement for cement.

Experimental Investigation of Sustainable Concrete Production using Blast Furnace as A Cement Substitute- A art of Review

The pursuit of sustainable construction practices has led to a growing interest in alternative materials that can reduce the environmental impact of traditional concrete production. This experimental study focuses on the utilization of blast furnace slag as a substitute for cement in concrete, aiming to assess its mechanical properties, environmental impact, and overall sustainability. The primary objectives of this research are threefold. Firstly, the study seeks to evaluate the mechanical properties of concrete by varying the content of blast furnace slag in the mix, with a specific emphasis on strength, durability, and structural performance. This involves conducting a comprehensive analysis of the concrete's compressive strength, flexural strength, and other relevant mechanical characteristics. Secondly, a life cycle assessment (LCA) will be employed to analyze the environmental impact of the concrete mixtures. This assessment will compare carbon dioxide (CO2) emissions, energy consumption, and overall sustainability of the concrete produced with varying percentages of blast furnace slag. The LCA will provide valuable insights into the environmental implications of using slag as a cement substitute, aiding in the identification of eco-friendlier concrete production practices. Lastly, the research aims to assess the environmental impact of blast furnace slag itself when employed as a cement substitute. This involves examining the production, transportation, and incorporation of blast furnace slag into the concrete mix, providing a holistic view of its sustainability across the entire life cycle. The experimental approach involves the meticulous design of concrete mixes with different percentages of cement replaced by blast furnace slag. The varying mix designs will be tested for mechanical properties, and the data obtained will be used to draw correlations between slag content and concrete performance. In summary, this research endeavors to contribute to the body of knowledge surrounding sustainable concrete production by exploring the mechanical, environmental, and sustainability aspects of utilizing blast furnace slag as a cement substitute. The findings of this study are anticipated to provide valuable insights for the construction industry to adopt more environmentally friendly practices while maintaining or enhancing concrete performance.

Multi-criteria decision making tool for sustainable concrete production using waste polyethylene terephthalate bottle cap aggregates

The widespread use of concrete has raised concerns about the consumption of its raw materials. To address this issue, researchers are actively exploring alternative waste materials to reduce the environmental impact of the construction industry. With this objective current study aims to investigate potential use of waste polyethylene terephthalate (PET) bottle cap aggregates on the characteristics of concrete, both in its fresh and hardened states. Three variations of modified waste PET aggregates (PETA): full (F), half (H), and quarter (Q), with the aim of evaluating their suitability as replacements for conventional coarse aggregates (CCA) was examined. The research assesses the effects of different PETA proportions (3%, 5%, and 8%) on concrete workability, compressive strength, splitting tensile strength, and flexural strength. The findings reveal that PETA-F and PETA-H adversely affect workability, primarily due to their larger surface area and difficulty in achieving homogeneous blending with other ingredients. In contrast, PETA-Q exhibits superior workability. The use of PETA-Q results in reduced compressive strength due to its smaller size and limited load-bearing capacity. Notably, PETA-H demonstrates improved compressive strength after 28 days. Interestingly, PETA-Q shows enhancements in splitting tensile and flexural strength, making it the top-performing alternative for fresh and hardened concrete properties. Overall, this research indicates that PETA-Q is most suitable for sustainable concrete production. Furthermore, the application of a multi-criteria decision-making tool validates our findings and determines that a 5% replacement of CCA with PETA is optimal, as higher replacements result in strength reduction. The utilization of PETA not only minimizes CCA consumption but also contributes to the development of eco-friendly, sustainable concrete. This study underscores the potential of environmentally conscious concrete and encourages the adoption of sustainable solutions for plastic waste management.

Response Surface Optimization of Rice and Guinea Corn Husk Ash Blended Concrete

Concrete, a fundamental construction material, consists of aggregates, water, cement, and additives. Unfortunately, the large-scale production of cement is a major contributor to carbon dioxide (CO2) emissions, primarily from the manufacturing process and the consumption of fossil fuels. This not only incurs environmental costs associated with global warming but also depletes vital limestone deposits. To mitigate these issues, this study aims to explore the optimal utilization of Guinea Corn Husk Ash (GCHA) and Rice Husk Ash (RHA) in concrete. This research investigated the chemical properties of GCHA and RHA, and their impact on the compressive and split-tensile strengths of concrete when integrated in various proportions. The study reveals that both GCHA and RHA meet the minimum oxide content requirement of 70% set by ASTM C618, with silicon dioxide (SiO2) as the predominant oxide. Increasing the content of RHA and GCHA from 5% to 10% improves the concrete's compressive and split-tensile strengths after curing for 56 days. Optimization results indicate that the ideal mix consists of 10% GCHA, 8.5% RHA, and 82.5% cement, yielding a compressive and split tensile strength of 31.34 N/mm² and 3.07 N/mm² respectively. This study thus offers a promising solution for sustainable concrete production by reducing the environmental footprint of cement while enhancing material properties and promoting an eco-friendlier approach to construction. Keywords: Concrete, Guinea Corn Husk Ash, Rice Husk Ash, Compressive Strength, Split-Tensile Strength

Sustainable concrete production using toxic foundry sand and its subsequent effect on water contamination

Amid growing concerns about diminishing river sand resources and escalating environmental apprehensions related to toxic landfill waste, this study explores the potential of Toxic Foundry Sand (TFS) as a substitute for Standard Fine Aggregate (SFA) in concrete production. The investigation into various TFS replacement ratios in M20 concrete focuses on their impact on workability and compressive strength. Although TFS exhibits properties similar to fine aggregate, making it a promising candidate for partial replacement, differences in bulk density and fineness modulus compared to river sand suggest that TFS should be utilized as a partial replacement only. The study proposes an optimal replacement ratio of 30 % TFS and 70 % SFA to achieve satisfactory compressive strength in M20 concrete. The workability of fresh concrete remains unaffected in both nominal and 70:30 mixes, ensuring ease of mixing on the job site. As an innovative aspect, the study includes testing the water exposed to TFS-infused concrete for portability. Prolonged exposure to water on TFS-infused concrete (70:30 mix) raises concerns, as certain parameters such as chloride and hardness exceed acceptable limits. Therefore, careful control and treatment of Toxic Foundry Sand Contact Water (TFSCW) are deemed crucial on job sites to address potential water quality issues and ensure overall environmental safety.

Exploring the Potential of Green Microalgae-Based Phycoremediation Treated Wastewater for Sustainable Concrete Production

Wastewater pollution from domestic, industrial, and agricultural sources threatens the environment and human health. Traditional wastewater treatment methods are energy intensive, generate significant sludge, and may not remove all contaminants. This study explores the use of microalgae, Chlorella sorokinianana, to treat wastewater and evaluates its impact on concrete properties. The research aims to optimize microalgae growth conditions, set up nutrient-rich growth chambers, develop biomass separation methods, and assess the effects of microalgae-treated wastewater on concrete. Scanning electron microscopy (SEM) was used to analyze concrete structures produced with microalgae-treated wastewater, freshwater, and sewage treatment plant (STP) water. Concrete from microalgae-treated wastewater exhibited euhedral crystals with pronounced gaps, while freshwater concrete had denser subhedral to anhedral crystals. STP water concrete consistently had lower strength values, possibly due to impurities affecting cement hydration. Microalgae-treated water concrete showed intermediate strength levels, suggesting organic or biological factors may influence hydration, but it still gained strength with time. This study underscores the potential of microalgae-treated wastewater for sustainable concrete production, highlighting the importance of further research to optimize conditions and promote environmentally friendly construction practices.

Optimization and characterization of sustainable geopolymer mortars based on palygorskite clay, water glass, and sodium hydroxide

Abstract The synthesis of ambient-cured sustainable geopolymer mortars (GMs) was studied throughout this work. To reduce carbon dioxide emissions, new materials must be used in the production of sustainable concrete and mortars. Many types of binders are used in the synthesis of GM and concrete (GPC), especially clay minerals. These clay minerals are considered sources of alumina and silica in GM and concrete. The geopolymerization process relies on the alkaline solution activating the alumino-silicate to produce geopolymer gel products. The palygorskite (PA) clay mineral, sodium hydroxide (NaOH), and sodium silicates (Na2SiO3) were chosen as a binder (solid material) and alkaline activator solution to synthesize GM at ambient temperature. PA was thermally treated at 550, 650, 700, and 750°C, respectively, to convert into high-reactive PA (HRP) HRP550, HRP650, HRP700, and HRP750, respectively. The characteristics of PA clay, HRP powders, and HRP-based GM were evaluated using compressive strength (CS) testing, X-ray fluorescence analysis, carbon footprint analysis, X-ray diffraction (XRD) diffractograms, Fourier transform infrared spectroscopy (FTIR) spectroscopy, scanning electron microscopy (SEM) images, and energy-dispersive X-ray spectroscopy (EDS) analysis. The maximum CS of 25.1 MPa was acquired for geopolymer synthesis utilizing HRP700-based GM cured at 30°C for 28 days. FTIR spectroscopy demonstrated that HRP-based GM showed the presence of Si–O, Al–O, and O–C–O bonds stretching vibrations in the alumino-silicate network. The results showed that the CO2 emissions had a reduction in the HRP-based GM compared with the reference mix of ordinary Portland cement mortar (OPM). The percentage of reductions was 14.1, 13.7, 13.1, and 12.4 for HRP550, HRP650, HRP700, and HRP750, respectively, compared with the OPM mixture. SEM images/EDS analysis and XRD diffractograms confirmed the presence of sodium alumino-silicate hydrates, magnesium silicate hydrate, and calcium silicate hydrate gels with high quantities particularly in the HRP700-based GM than that in HRP550, HRP650, and HRP750, respectively. The results indicate the suitability of HRP calcined at 700°C (HRP700) in the synthesis of the GM.

Influence of High-Density Polyethylene Admixtures on Water Sorptivity Behaviour of Medium and High strength Concretes

The increasing research interest in the reuse of waste plastics have presented vast potentials for improving concrete properties and contributing to sustainable concrete production. This work studied the sorptivity behaviour of grades M25 and M50 concretes prepared using pulverised high density polyethylene (HDPE) immersed in 20% hydrogen peroxide as treatment. As an additive, the pulverised HDPE was added to the concrete at 0 %, 0.25 %, 0.5 %, 0.75 %, and 1 % based on cement weight. The concrete had been made with 150 mm3 steel moulds using mix design method. A super plasticiser -Hydroplast-500, was used in the mixes. For the grades M25 and M50 concretes, respectively, 0.4 and 0.36 water/cement ratios had been selected to represent medium and high strengths concretes after 7, 28, and 90-day periods of water cure. After being taken from the water and dried, the concrete cubes underwent a sorptivity test. Results obtained indicated that incorporation of treated HDPE to the concrete reduced its sorptivity up to 59 % and 64.5 % respectively for grades M25 and M50 concretes due to the admixture's existence in the mix. The study recommends concrete prepared with 1 % HDPE by weight of cement for use in water retaining structures, drainage systems and constructions where damp is a challenge to existing infrastructure.

Characteristics of non-steady-state chloride migration of self-compacting concrete containing recycled concrete aggregate made of fly ash and silica fume

Chloride migration poses a significant challenge to the long-term durability of concrete structures due to its potential to corrode reinforcement and deteriorate the structure. This study focuses on chloride migration in self-compacting concrete (SCC) made with pozzolans, namely silica fume (SF) and fly ash (FA), along with recycled concrete aggregate (RCA). Particularly, the effects of external electrical potential (power-on) duration and RCA content on the features of SCC were examined, alongside the influence of pozzolanic materials, focusing on the chloride migration coefficient and mechanical properties. Six groups of SCC mixtures were created with varying proportions of SF and FA, and different levels of RCA replaced the natural coarse aggregate. The findings reveal a multifaceted impact on SCC behaviour. The chloride migration coefficient exhibits a distinct pattern as the power-on duration increases from 12 to 36 h. Initially, the coefficient increases and then decreases, demonstrating a healing and sealing mechanism within the concrete matrix, which enhances resistance to chloride penetration. The chloride migration coefficient significantly decreased with adding SF and FA. With 15% SF and 30% FA, the coefficient decreased to 59.9% and 49.5%, respectively. Moreover, incorporating RCA in SCC mixtures significantly influences coefficient levels. RCA inclusion at 20% remarkably decreased the coefficient after 12 h by 16.17%. Subsequently, the levels decreased by 39.49% and 46.87% after 24 and 36 h, respectively, compared to the control mixture. This behaviour highlights the importance of RCA in enhancing the resistance of SCC to chloride ingress, a crucial factor for long-term durability. Additionally, mechanical properties such as splitting tensile strength, ultrasonic pulse velocity and surface hardness consistently improved with longer power-on durations and higher RCA and SF content. SCC with RCA and pozzolanic materials exhibits enhanced chloride resistance and superior mechanical performance, making it ideal for sustainable concrete production.

Development and evaluation of basaltic volcanic ash based high performance concrete incorporating metakaolin, micro and nano-silica

High-performance concrete is an excellent choice for modern engineering structures due to its superior performance, low maintenance costs, and long service life. Therefore, this study was aimed to produce high-performance concrete by incorporating a high volume of basaltic volcanic ash along with metakaolin (MK), micro-silica (MS), and nano-silica (NS). An investigation was performed in regard to the mechanical and durability properties, autogenous and drying shrinkage, and microstructural and pore-structure properties. A control mix, binary mixes, and ternary mixes were examined. The binary mixes contained fine (VA) and ultra-fine (VAF) volcanic ashes, and the ternary mixes contained combinations of VA with MK, MS, and NS. Test results show that ternary mixes with 30% and 40% cement substitution demonstrated better strength development and higher resistance to chloride penetration and water absorption. All binary and ternary mixes displayed lower autogenous shrinkage, as well as lower or comparable drying shrinkage than the control mix. Moreover, the combination of VA with MK, MS, and NS up to 40% resulted in micro and pore structure refinement by forming high-density gels. The findings indicate that VA in combination with MK, MS, and NS, can effectively substitute cement at up to 40% for the production of sustainable high-performance concrete.

Sustainable development and performance assessment of concrete incorporating biofuel waste

This study focuses on investigating concrete's engineering properties when sugarcane bagasse ash (SCBA) is used as a partial substitute for cement. SCBA is obtained by sintering bagasse at 700 °C for one hour. The research analyzes various properties of SCBA concrete at different water-cement ratios (0.3, 0.4, 0.5) and curing periods (7, 28, 56, and 91 days), including fresh-mixed properties (slump, flow, unit weight, setting time), engineering characteristics (compressive, splitting strength, pozzolanic index, ultrasonic pulse velocity (UPV), resistivity, sulfate attack, and water absorption), and microscopic properties. Key findings indicate that replacing 5% cement with SCBA improves workability, but higher substitution levels reduce workability and accelerate setting times. Compressive and splitting strength decrease with increased SCBA substitution, but still meet acceptable standards. UPV follows a similar trend. In terms of durability, concrete resistance improves with higher SCBA substitution. The study suggests that incorporating 5% SCBA enhances the hydration reaction of cement, leads to superior strength, UPV, lower water absorption, and reduced weight loss in sulfate tolerance tests, and improves long-term durability. The research underscores the potential of SCBA as a valuable resource for environmentally responsible and sustainable concrete production.

Enhancing concrete performance: Surface modification of recycled coarse aggregates for sustainable construction

In this study, the researchers introduce an innovative method to enhance the utilization of recycled coarse aggregates (RCA) derived from construction and demolition waste (C&D) in sustainable concrete production. The presence of old cements mortar on the surface of these aggregates poses a challenge to their mechanical properties. To tackle this issue, the researchers propose a unique approach that combines chemical treatment and abrasion techniques. Firstly, RCA is immersed in a 0.5 mol hydrochloric acid (HCl) solution, weakening the adhering mortar. Subsequently, abrasion treatment removes the weakened mortar from the RCA surface. The study explores the incorporation of these surface-modified RCAs at varying levels, from 0% to 100% in 25% increments. Various concrete properties, including workability, compressive strength, flexural strength, split tensile strength, and microstructural characteristics (XRD, SEM, and EDAX), along with modulus of elasticity, are assessed. Results indicate that the combination of these modification techniques significantly enhances RCA properties. At the 100% replacement level, surface-modified RCA results in a reduction of compressive, flexural, and split tensile strength by 08.31%, 10.61%, and 07.90%, respectively, in comparison to the reference concrete. Likewise, the modulus of elasticity decreases to 30.82, and porosity decreases to 27.82% at the same replacement level. However, SEM analysis illustrates improved bonding between RCA and cement matrix due to surface modifications, leading to reduced porosity and the formation of dense Interfacial Transition Zones (ITZs). Cost analysis reveals that recycled aggregate concrete (RAC) mixtures can be more economical than those utilizing natural aggregates (NA). In summary, this novel surface modification technique presents a promising avenue for optimizing RCA utilization in sustainable concrete production, promoting environmental conservation, and efficient waste management in the construction sector.

Comparison of environmental impacts of fly ash and slag as cement replacement materials for mass concrete and the impact of transportation

For mass concrete applications, the utilization of waste as supplementary cementitious materials (SCM), such as fly ash and slag, can enhance sustainability. This study aims to provide and compare the environmental impacts associated with utilizing fly ash and slag, considering their modes of transportation. Both land and maritime sea transportation are investigated. The environmental impacts of mass concrete mixtures with 65% ground-granulated blast furnace slag (65GGBS) and 50% fly ash (50FA) as cement replacement were investigated using cradle-to-gate life cycle analysis in Thailand context. Results show that fly ash (164 kg CO2 eq, 54% reduction) and GGBS (141 kg CO2 eq, 61% reduction) reduce the global warming potential of pure-cement concrete (357 kg CO2 eq) without considering SCM transportation. However, the processing of GGBS increases marine eutrophication and human carcinogenic toxicity by 4.59 and 3.89 times, respectively, compared to the cement-only mixture. Due to maritime shipping, the environmental performance of 65GGBS concrete exceeds that of pure cement mixtures in 15 impact indicators. The largest proportion of terrestrial acidification (92%), ozone formation (90%), and fine particulate matter (88%) is attributable to long distance maritime transportation. All the environmental impacts from 50FA are lower than those associated with pure-cement concrete at a land transportation distance of 190 km. Regarding endpoint impacts, 65GGBS is better than 50FA in reducing harm to human health and the ecosystem. This study's findings emphasize the importance of considering SCM type, transportation logistics, and their intricate interplay, providing valuable insights for sustainable concrete production.

Production of Sustainable Concrete from Agro-Wastes ash

Production of Sustainable Concrete from Agro-Wastes ash

Analysis of the Technical Feasibility of Sustainable Concrete Production Using Waste Foundry Sand as a Fine Aggregate

Analysis of the Technical Feasibility of Sustainable Concrete Production Using Waste Foundry Sand as a Fine Aggregate

Formulation of inexpensive and green reactive powder concrete by using milled-waste-glass and micro calcium-carbonate – A multi-criteria optimization approach

In view of its high strength and durability, reactive powder concrete (RPC) is a promising construction material. The replacement of cement and silica fume with sustainable alternatives to RPC may provide significant benefits, however, there are challenges to overcome. In this study, calcium carbonate and ground waste glass powder were introduced as mineral mixtures to develop an environmentally friendly and cost-effective RPC mixture. The best flowability, proper compressive strength, and reduced cement content were achieved using a multi-objective simultaneous optimization approach based on the Derringer & Suich methodology. As a result of the study, 603 kg/m3 of cement was determined as the most suitable dosage for RPC. Additionally, the optimized mix contained 368 kg/m3 of waste glass and 118 kg/m3 of calcium carbonate, which had a beneficial impact on both cost and environmental considerations. As a result of numerous experimental tests, including compressive strength, elasticity modulus, chloride ion penetration, and drying shrinkage, the developed RPC's properties were validated and were comparable to the control mixture while showing superior drying shrinkage behavior. A further benefit of adding these admixtures was the reduction of superplasticizer dosage. Despite the optimized RPC's lower mechanical and chloride ion penetration performance at early ages, the performance discrepancy diminished over time due to the pozzolanic properties of waste glass powder. A significant characteristic of the optimized RPC was its superior drying shrinkage behavior throughout the testing period resulting from its reduced water dosage. Ultimately, the study highlights the potential of the addition of calcium carbonate and waste glass powder to RPC for sustainable concrete production at a low cost.

Characteristics on compressive strength and microstructure of high-strength cementitious composites with waste glass beads

This study investigated the potential of waste glass beads (WGB), a recycled porous lightweight material derived from waste glass, to enhance long-term curing of moisture-saturated cementitious construction materials. The macroscopic properties and microstructure development of a cement composite material blended with two types of WGB––spherical (B) and crushed (CB)––were analyzed. The primary objective was to provide practical guidelines for optimizing WGB utilization as a moisture release medium and thus contribute to sustainable concrete production by exploring waste glass applications. This study demonstrated the potential of WGB for improving strength and void structure and could help enhance the long-term durability of cement composites. Valuable insights were gained regarding the surface roughness and specific surface areas alongside curing methods to maximize WGB's effectiveness. The key contributions are as follows: (1) varying effects on high-strength concrete (HSC) strength with increased WGB content and surface roughness and specific surface areas were analyzed; (2) a proportional relationship between closed pore volume and modulus affecting macroscopic properties was revealed; (3) insights into hydration product presence in the ITZ and its relationship with WGB moisture content were gained; and (4) notable improvements in indentation tests for specimens with WGB were achieved, indicating enhanced ITZ hydration and increased density within both ITZ and paste.