Cement Usage Research Articles

Study on the Influence of Density and Water–Cement Ratio on the Cement Utilization, Fluidity, Mechanical Properties, and Water Absorption of Foam Concrete

In this paper, we study the influence of density and the water–cement (W/C) ratio on the slurry fluidity, compressive strength, and water absorption of foamed concrete (FC) and its mechanism of action, with the aim of proposing an optimal mix ratio for FC to reduce cement usage and carbon emissions in the construction industry and ensure the good overall performance of FC. In this experiment, two groups of experiments were designed using the control variable method. Fluidity and uniaxial compression tests showed that when the density was 600 kg/m3 and the W/C ratio was 0.6, the FC slurry had maximum fluidity, but its mechanical properties were poor and it collapsed easily. Conversely, by analyzing the uniaxial compressive strength/cement (UCS/C) ratio, it was observed that the mix ratio had a maximum cement utilization rate (W/C ratio) of 0.5 and a density of 1000 kg/m3. Nondestructive testing methods were used to measure the ultrasonic pulse velocity (UPV) and rebound value of the FC test block, and the strength and durability of FC were analyzed. The water absorption rate of the FC test block was tested, and the final analysis showed that the optimal mix ratio of FC in this test was W/C = 0.5, with a density of 1000 kg/m3.

Improvement of the Sand Quality by Applying Microorganism Induced Calcium Carbonate Precipitation to Reduce Cement Usage

This research aimed to study the utilization of microorganisms in the soil. These microorganisms were applied to improve the quality of soil and sand to reduce cement consumption. The process of microbial-induced precipitation of calcium carbonate (MICP) was used in this study, a bonding process to create a binding between sand particles from the naturally occurring processes of microorganisms. The study was conducted to determine the maximum growth rate of bacteria (maximum growth curve) of five strains as follows Proteus mirabilis TISTR 100, Bacillus thuringiensis TISTR 126, Staphylococcus aureus TISTR 118, Bacillus sp. TISTR 658 and Bacillus megaterium TISTR 067 in Nutrient Broth (NB) culture medium at 37°C. Christensen's Urea Agar slant (UA) was a preliminary screen for urease-producing bacteria. The color change of indicator color was seen in the slant, comparing the results (+) and control (-). The researchers have selected bacterial strains capable of producing significant amounts of enzymes to hydrolyze urea. It was found that the amount of calcium carbonate sediment produced by five strains of bacteria, namely Proteus mirabilis TISTR 100, Bacillus thuringiensis TISTR 126, Staphylococcus aureus TISTR 118, Bacillus sp. TISTR 658 and Bacillus megaterium TISTR 067 had the amount of sediment produced as follows: 3.430, 3.080, 2.590, 1.985, and 1.615 mg/ml, respectively. It was found that the species Bacillus sp. TISTR 658 does not produce the most calcium carbonate sediment. Nevertheless, it made the sand samples stick together tightly and form the perfect lumps. Therefore, improving the sand's composition has shown the potential to apply the MICP process to reduce the cement used.

Engineered Cementitious Composite with Nanocellulose and High-Volume Fly Ash

This research develops a sustainable Engineered Cementitious Composites (ECC) with reduced cement usage by incorporating high volume fly ash (HVFA) and silica fume, along with the novel application of nanocellulose (NC), a plant-based nanomaterial, and hybrid fibres to achieve high strength and ductility simultaneously. 12 mixes were developed including three base ECC mixes with 1.5% polyethylene (PE) and 0.5% steel fibres with varying proportions of fly ash and silica fume (1.2:0-1:0.2) and nine NC reinforced ECC mixes with varying dosages of NC (0.15%, 0.2%, 0.25% by weight). The effect of fly ash/silica fume ratio and NC on mechanical properties was investigated through compressive and uniaxial tensile tests. Scanning electron microscope (SEM) and differential scanning calorimetry (DSC) techniques were utilized to gain insights into the HVFA and NC matrix systems and NC and hybrid fibre mechanism. Results showed that reducing the fly ash/ silica fume ratio increased strength but reduced tensile strain. Incorporating NC improved strength across all mixes, irrespective of fly ash/silica fume content, with the mix containing 0.2% NC showing the highest improvement. This novel ECC is anticipated to offer a sustainable and high-performance material solution for engineering structures.

Optimizing plastic waste inclusion in paver blocks: Balancing performance, environmental impact, and cost through LCA and economic analysis

Rising waste plastic and cement used in construction raises environmental concerns. Substituting cement with recycled plastic waste (PW) in paver blocks offers an eco-friendly solution. However, a comprehensive life cycle assessment (LCA) economic and performance analysis is lacking. This study addresses this gap by evaluating the compressive strength and durability properties of PSPB while also conducting LCA and economic evaluations to identify the most optimal solutions for enhanced performance. Compressive strength tests determined that a 30% PW replacement yielded optimal results. The durability tests showed that PW paver blocks have significantly lower water absorption compared to conventional blocks, and they maintained a compressive strength of 20 MPa, which is acceptable for light traffic applications, even at elevated temperatures. LCA highlights that cement usage accounts for over 80% of climate change emissions for conventional blocks. Sensitivity analysis shows shipping distance, truck capacity, and energy use greatly affect environmental outcomes. Complete replacement of cement with PW is considered more environmentally friendly. Economic analysis indicates plastic pavers are 52% more cost-effective than cement-based ones. This research offers vital insights into the practicality, environmental impact, and financial sustainability of integrating PW into paver blocks.

Approach to Design Sustainable Alkali-Activated Slag Recycled Aggregate Concrete: Mechanical and Microstructural Characterization

There is a steep increase in demand for concrete as the need for infrastructure is increasing with a rapid increase in urbanization. Consequently, there has been a surging demand for cement across the globe. By using alkaline concrete activated with ground granulated blast furnace slag (GGBS), cement usage can be eliminated in concrete, which addresses the issue of CO2 emissions concerned with the cement manufacturing process and promotes the use of industrial by-products as sustainable building materials. The current study focuses on proposing a methodology to design sustainable GGBS-based alkali-activated concrete incorporated with 100% coarse recycled coarse aggregates (RCA) recovered from construction and demolition (C&D), for various strengths by optimizing the mix proportions and verifying the same through experiments. From the current study, it is evident that this mix design procedure can be adopted to design alkali-activated slag recycled aggregate concrete (AASRAC) mixes for strengths ranging from 44MPa to 85MPa. The optimum values of alkalinity factor (λ) and NaOH concentration (M) i.e., 1.5 and 12, have a significant role in the development of high strengths which is attributed to the formation of hydrotalcite. Micrographs captured using scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) studies reveal that the alkaline binders promote the development of a denser and stronger interfacial transition zone (ITZ) that enhances the strength of lower AA/B concretes at the microstructural level as Ca/Si ratio is higher for lower AA/B concretes. Global warming potential (GWP) analysis reveals that the alkali-activated concretes have significantly lower GWP compared to conventional OPC-based concrete by approximately 2.5 times. The mix-design chart proposed in this study may pave the way to designing structural grade AASRAC with enhanced performance for the desired strength, which may find its application in fast-track construction and manufacturing of prefabricated elements.

Novel Retrofitting Technique for Beam by External Wrapped with Glass Fiber and Internally Embedded Damper System for Sustainable Construction

Abstract Reinforced concrete structures are often exposed to extreme loads, such as those from sudden and accidental impacts. This has led to an increasing interest in strengthening these structures, improving their fatigue performance, and extending their service life, particularly for components like beams. A more sustainable approach to maintaining their functionality involves strengthening and repairing damaged components. Therefore, glass fiber polymers are ideal reinforcements for retrofitting due to their high tensile strength and low cost compared to other polymer substitutes This paper presents the performance of plain concrete beams reinforced externally with glass fiber sheets (GFS) and dampers embedded internally. A unique methodology has been adopted to improve the adhesion between the fiber glass sheets (GFS) and the concrete surface. Two adhesive components utilized are epoxy resin (ER) and epoxy hardener (EH), mixed in a ratio of 9:1. Internally embedded dampers are devices used to resist lateral forces on structures, particularly during impact or sudden loading. The adopted damper technique involves incorporating chopped Glass Fiber during the casting process of the dampers. These dampers are subsequently embedded into beams at point of failure. After the curing of 28 days, all the cast beam compositions undergo flexural test, and dampers are tested for compressive strength. After the dampers have undergone compression testing, a microstructural analysis is conducted using SEM (Scanning Electron Microscope). For further details on stress formation in beams, finite element analysis of Ansys is used to model beams for all beam compositions. Also, sustainability goals are addressed by reducing cement usage in construction by introducing retrofitting in older buildings and using this system to improve the design of newer buildings by reducing overall section sizes

Innovative hybrid machine learning models for estimating the compressive strength of copper mine tailings concrete

The growing demand for copper and related materials in various industries is driving increased copper mining globally. This surge presents a substantial challenge in managing and responsibly disposing of large volumes of copper mine tailings (CMT). Incorporating CMT as supplementary cementitious materials (SCMs) in concrete addresses two significant environmental challenges simultaneously: reducing the accumulation of CMT waste in landfills and lowering the carbon footprint by reducing cement usage. The investigation into recycling CMT as a cement substitute involves a thorough assessment of its impact on the compressive strength (CS) of concrete. This research introduces innovative hybrid machine learning (ML) models for estimating the CS of CMT concrete, aiming to streamline strength assessment processes and save valuable resources. The method involves integrating features from large public datasets with the limited available data on the CS of CMT concrete. Support vector regression (SVR) was combined with advanced optimization techniques: firefly algorithm (FFA), grey wolf optimization (GWO) and particle swarm optimization (PSO) to create new hybrid models for forecasting the CS of CMT concrete. Additionally, traditional ML techniques like decision tree (DT) and random forest (RF) were used to compare with these SVR-based hybrids. All three hybrid models demonstrated strong performance, with SVR-FFA emerging as the most effective among them. Notably, SVR-FFA achieved the greatest R² score of 0.96, indicating superior predictive accuracy compared to SVR-PSO (0.92) and SVR-GWO (0.90). Additionally, the DT model attained an R² score of 0.88, while the RF model achieved an R² score of 0.84. Moreover, the SHapley additive exPlanations (SHAP) and partial dependence plots (PDP) analyses underscore the positive effects of curing age, cement, blast furnace slag, and superplasticizer on the CS of CMT concrete. A graphical user interface was developed for predicting the CS of CMT concrete, allowing for instant predictions without the need for conducting experiments.

Enhancing Recycled Concrete Performance by Using Chemical Activators

The need for sustainable and eco-friendly construction materials and processes is rising significantly. In these circumstances, recycling of concrete can be a lifesaver. Although, various recycling techniques have already been introduced. But none of them can fulfill the term recycle refers to. They mostly focus on merely reusing coarse aggregates (CA) or fine aggregates (FA). To come out of this, this paper is focused not only on the reuse of both coarse and fine materials (RCA, RFA) but also on introducing a new process in which those materials can be used in their old form, as recycling refers to. In this experiment, we use all kinds of materials recollected from recycled concrete (fine, coarse, recycled cement particles). Those materials are vetted into two parts. One is for recycling coarse aggregates and one is for rebuilding concrete using recovered fine, coarse, and cement particles. First, we discuss the collection and treatment system procedure of recycled demolished concrete. The second part will consist of various standardized tests for reuse and evaluation. The third part will describe the treatment needed for the materials for chemical (Using Na2SiO3, NaOH, and Na2CO3) reactivation. Finally, we will test the recycled material’s performance as concrete and establish an authentic process of recycling and reusing concrete materials. With that, we obtain the most optimum usage of recycled concrete aggregate mixing ratio Cement: CA (coarse aggregate): RCA (recycled coarse aggregate): FA (fine aggregate): RFA (recycled fine aggregate) is 1: 2: 2: 0.8: 1.2: 0.8 (With molar solution of Na2SiO3 and NaOH + KOH) and other ration of mixing with their respected properties (Compressive Strength).

Investigation of Sugarcane Bagasse Ash (SBA)-Based Engineered Geopolymer Mortar Reinforced with Coconut Fibre for Engineered Geopolymer Composites

In recent years, there have been growing demand for fibre-reinforced cementitious composites using materials wastes to reduce cost and cement usage in concrete production. Therefore, this study aims to prepare sugarcane bagasse ash (SBA)-based geopolymer reinforced with coconut fibre as a material suitability evaluation for engineered geopolymer composites. The sugarcane baggase ash was characterised for its physical and chemical properties using scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDS), X-ray powder diffraction (XRD). The coconut fibres was added at 0%, 1%, 2%, and 3%, while the plain cement mortar was used as the control mix. Both destructive (compressive and tensile strength) and non- destructive test (water absorption, and ultrasonic pulse velocity test) were conducted on the resulting geopolymer mortar. The result of the SBA characterisation showed that the SBA met the ASTM C618 requirement for a pozzolanic material. The addition of 1% fibre to the geopolymer composite resulted in enhanced durability property than the plain cement mortar. The ultrasonic pulse velocity test demonstrated that bagasse ash-based geopolymer composites can be classified as a excellent cementitious material. The study also found the engineered cementitious composite showed better compressive and tensile strength than the plain concrete mortar, while the addition of fibre provided a denser microstructure for additional strength. The optimum fibre content was found at 1% for improved water absorption performance, UPV, and compressive strength. The study concludes that SBA composite reinforced with coconut fibre can provide better alternatives to achieve sustainability in engineered geopolymer concrete applications.

Enhancing lateritic soil for sustainable pavement subbase with polymer-modified cement: A comparative study of styrene butadiene rubber and styrene acrylic latex applications

This study evaluates styrene butadiene rubber (SBR) and styrene acrylic latex (SA) as modifiers in cement-treated subbase materials (CTSB) to enhance mechanical properties and reduce cement usage sustainably. Optimal ratios for stabilizing sub-standard lateritic soils were identified, reducing water demand and increasing mechanical strength in polymer-modified cement pastes. A 10 % SA and a 15 % SBR as cement replacement by mass significantly improved bearing strength and strain capacities in CTSB, signifying enhanced flexibility and elasticity. Despite slight changes in compaction characteristics, the study identified 1.6 % SA and 2.4 % SBR as optimal binder (i.e., polymer-cement mixture) contents, compared to 3.3 % cement for conventional CTSB with similar unconfined compressive strength standards. SBR-enriched CTSB exhibited superior resilient modulus, indicating stronger inter-particle bonding. The integration of SA and SBR reduced capillary rise and enhanced moisture stability. This sustainable approach enhances pavement durability and reduces CO2 emissions by minimizing cement use. The findings emphasize the potential of polymer-modified CTSB for cost-effective and environmentally friendly road construction, offering significant implications for advancing pavement engineering materials and promoting eco-friendly practices within the industry.

Toward sustainability: Integrating experimental study and data-driven modeling for eco-friendly paver blocks containing plastic waste

Abstract Plastic waste (PW) poses a significant threat as a hazardous material, while the production of cement raises environmental concerns. It is imperative to urgently address and reduce both PW and cement usage in concrete products. Recently, several experimental studies have been performed to incorporate PW into paver blocks (PBs) as a substitute for cement. However, the experimental testing is not enough to optimize the use of waste plastic in pavers due to resource and time limitations. This study proposes an innovative approach, integrating experimental testing with machine learning to optimize PW ratios in PBs efficiently. Initially, experimental investigations are performed to examine the compressive strength (CS) of plastic sand paver blocks (PSPBs). Varied mix proportions of plastic and sand with different sizes of sand are employed. Moreover, to enhance the CS and meet the minimum requirements of ASTM C902-15 for light traffic, basalt fibers, a sustainable industrial material, are also utilized in the manufacturing process of environmentally friendly PSPB. The highest CS of 17.26 MPa is achieved by using the finest-size sand particles with a plastic-to-sand ratio of 30:70. Additionally, the inclusion of 0.5% basalt fiber, measuring 4 mm in length, yields further enhancement in outcome by significantly improving CS by 25.4% (21.65 MPa). Following that, an extensive experimental record is established, and multi-expression programming (MEP) is used to forecast the CS of PSPB. The model’s projected results are confirmed by using various statistical procedures and external validation methods. Furthermore, comprehensive parametric and sensitivity studies are conducted to assess the effectiveness of the MEP-based proposed models. The sensitivity analysis demonstrates that the size of the sand particles and the fiber content are the primary factors contributing to more than 50% of the CS in PSPB. The parametric analysis confirmed the model’s accuracy by demonstrating a comparable pattern to the experimental results. Furthermore, the results indicate that the proposed MEP-based formulation exhibits high precision with an R 2 of 0.89 and possesses a strong ability to predict. The study also provides a graphical user interface to increase the significance of ML in the practical application of handling waste management. The main aim of this research is to enhance the reuse of PW to promote sustainability and economic benefits, particularly in producing green environments with integration of machine learning and experimental investigations.

Sustainable Pervious Concrete with Silica Fume as Cement Replacement: A Review

Pervious concrete is a unique type of concrete with high porosity that allows water to pass through. This characteristic makes it beneficial for various applications, such as stormwater management, groundwater recharge, and reduced heat island effect. However, pervious concrete typically requires more cement than conventional concrete because of its mix design. This increased cement content can be partially replaced with supplementary cementitious materials, such as silica fume. This review article investigates the influence of silica fume on the properties of pervious concrete, including the mechanical properties (compressive strength, splitting tensile strength, and flexural strength), durability (resistance to freeze–thaw cycles and abrasion), and environmental aspects. The article highlights that silica fume can improve the mechanical properties and durability of pervious concrete up to an optimal replacement level. The optimum replacement level of cement with silica fume was found to be 10%–15%. Beyond this level, the performance of pervious concrete decreases. The pervious concrete containing silica fume showed superior abrasion resistance and improved freeze–thaw resistance compared to conventional pervious concrete. In addition, incorporating silica fume in pervious concrete reduces cement usage, leading to a lower environmental impact and more sustainable construction practices. The article also analyzes the limitations of using silica fume, such as the potential for reduced workability because of its fine particle size. Overall, the review suggests that silica fume is a promising supplementary cementitious material for enhancing the performance and sustainability of pervious concrete.

Applicability and chemical mechanism of lightweight cement composite containing fly ash and sand for sustainable embankment

Lightweight embankment is an effective method for soft foundation treatment, while decreasing its cement usage can protect environment, save resource and reduce cost. This study aims to develop a lightweight cement composite (LC) containing fly ash and sand to provide guidance for filling the sustainable embankment. The chemical mechanism, micro-morphology, mechanical strength and workability of lightweight cement composites were evaluated through macro-micro tests, as well as life cycle assessment was performed to analyze the sustainability, and determine the optimal mixing ratio. The results showed that the moderate amount of fly ash was beneficial to enhance the mechanical strength of LC, while adding sand further improved its ductility, toughness, workability and sustainability. When the replacement rate of fly ash and sand were 10 % and 20 %, the energy absorption and fluidity of LC increased by 57 % and 7 %, and its ductility index, carbon emission and construction cost decreased by 34 %, 46 % and 35 %, respectively. Fly ash reacted with calcium hydroxide produced by cement hydration to generate more calcium silicate gels, which reduced the large pore of LC and improved its internal structure, while sand played a certain skeleton role.

Mechanical properties of rice husk ash and glass powder concrete: Experimental and mesoscopic studies

Using glass powder and rice husk ash as supplementary cementitious materials (SCM) can effectively reduce cement usage, protect the environment, and promote waste recycling. In this study, ordinary concrete, glass powder concrete, and glass powder rice husk ash concrete were studied through a series of experiments, including tests for slump and water absorption, uniaxial compression, variable angle shear, cyclic compression, and numerical simulation. The following results were identified. Glass powder increases the slump of concrete and reduces its water absorption, whereas the opposite is the case with the addition of rice husk ash. The uniaxial compressive strength of glass powder concrete is higher than that of ordinary concrete at 28 days of curing. Glass powder concrete has the maximum bearing capacity, in terms of the shear test. The minimum damage index is shown under cyclic compression. When the rice husk ash content is 15 %, the combination with glass powder has the strongest pozzolanic effect, while the replacement rates of 30 % and 45 % are not suitable for pozzolanic materials. The dissipation energy conversion rate of the sample containing rice husk ash is always greater than the elastic strain energy conversion rate. In addition, the samples containing rice husk ash showed ductile failure and reduced cracks during compression. This study can provide new insights into the combination of glass powder and rice husk ash as SCM.

Mitigating the brittle behavior of compression cast concrete using polypropylene fibers

Compression casting enhances mechanical properties, durability, and microstructure of concrete while reducing cement usage and carbon emissions. However, its brittleness restricts its widespread use. This study aims to mitigate the brittleness of compression cast concrete (CCC) through fiber reinforcement. Eleven concrete mixes with varied volumetric ratios (0, 0.05, 0.1, 0.15, 0.2, and 2 %) and aspect ratios (250, 313, and 396) of polypropylene fibers were prepared. Both compressed and uncompressed specimens were analyzed for compressive stress-strain behavior, compressive strength, modulus of elasticity, toughness, specific toughness, and microstructure. Results show that CCC specimens have steeper and shorter descending segments on their compressive stress-strain curves than uncompressed concrete, indicating brittleness. Adding polypropylene fibers significantly reduces this brittleness by enhancing the post-peak compressive stress-strain behavior of CCC. Fiber reinforced CCC specimens exhibit significant enhancements in compressive strength, modulus of elasticity, and toughness (up to 68 %, 34 %, and 38 % respectively) compared to uncompressed plain concrete. Mercury intrusion porosimetry, scanning electron microscopy, and backscattered electron imaging confirm that compression casting strengthens the interfacial transition zone of both plain and fiber reinforced CCC. Proposed empirical models accurately forecast the modulus of elasticity, compressive strength, and peak compression strain for both types of CCC. Comparisons with existing models show that Nematzadeh and GB50010–2010 models effectively predict the ascending part of the compressive stress-strain curves of plain and fiber reinforced CCC. These findings affirm that polypropylene fibers effectively reduce the brittleness of CCC, promoting its practical application.

Enhancing sustainability in concrete production: A novel compression casting technique for optimizing cement usage

Cement manufacturing is a major source of carbon dioxide (CO2) emissions. This study focuses on using the compression casting method to reduce the cement content in concrete manufacturing. No such work is present in the existing literature. For this purpose, five concrete mix designs of normal concrete (NC) and compression cast concrete (CCC), targeting compressive strengths of 50 MPa, 30 MPa, 25 MPa, 20 MPa, and 15 MPa, were considered. Moreover, considering the reduced cement content, five additional concrete mixes of NC and CCC were also prepared. All concrete specimens were tested in axial compression to study the stress-strain behavior. The findings reveal that CCC specimens exhibit higher stress-strain curves compared to NC specimens for the same mix design. The post-peak behavior of CCC specimens is observed to be more brittle than that of NC specimens. The reduction in density, compressive strength, and elastic modulus with the increase in the water-to-cement (w/c) ratio is more pronounced in NC specimens than in CCC specimens. The results indicate that the compression casting method allows for a reduction in cement content by approximately 25–50 % while achieving the desired compressive strengths, ranging from 30 to 50 MPa. A correlation is clearly demonstrated to determine the potential cement savings for specific concrete strengths. In summary, adopting compression casting technology effectively lowers cement requirements, leading to cost and carbon emission reductions in the construction sector and significantly enhancing the durability of concrete materials.

Improvement of the Sand Quality by Applying Microorganism-induced Calcium Carbonate Precipitation to Reduce Cement Usage

This research determines the Microbially Induced Calcium Carbonate Precipitation (MICP) process utilized by the bacteria found in Thailand. Many researchers typically use the high-efficiency MICP bacteria to precipitate calcium carbonate. However, it is only available in some countries, leading to a high import expense. Therefore, the methodology for using the bacteria capable of producing calcium carbonate in Thailand was investigated. The five pure bacteria strains are obtained from the Thailand Institute of Scientific and Technological Research (TISTR), i.e., Proteus mirabilis TISTR 100, Bacillus thuringiensis TISTR 126, Staphylococcus aureus TISTR 118, Bacillus sp. TISTR 658 and Bacillus megaterium TISTR 067. To screen urease production, the bacteria were spread on Christensen's Urea Agar (UA) slant surface via a colorimetric method. All bacteria strains can produce urease enzymes by observing the color changes in the UA. Berthelot's method was used to determine the urease activity. The result shows the bacteria's urease activity: 2389, 1989, 1589, 789, and 589 U/ml, respectively. These directly lead to calcium carbonate production: 3.430, 3.080, 2.590, 1.985, and 1.615 mg/ml, respectively. Despite the bacteria in this research having a low precipitation efficiency compared to the strain used in many research studies, they can improve sand stabilization in 7 days. Proteus mirabilis TISTR 100 was the most stable and effective strain for the MICP process in Thailand. Hence, this research reveals the ability of the local bacteria to bond with the sand particle. Briefly, the improvement of the MICP process in sand stabilization can be improved to reduce imported expenses. In addition, the MICP process can reduce the use of cement in sand stabilization work.

Experimental analysis of the impact of alternating magnetic fields on the compressive strength of concrete with various silica sand and microsilica compositions

This research experimentally assessed the compressive strength enhancement of 7- and 28-day concrete specimens with up to 20 % silica sand and micro silica under an alternating magnetic field up to 1 Tesla. By applying magnetic fields to hardened concrete, properties can be tailored to specific needs, thus lowering cement usage and CO2 production. It was found that adding 10 % micro silica reduced the compressive strength at 7 and 28 days, while using 10 % silica sand and 5 % micro silica increased the compressive strength by 14.55 % and 7.79 %, respectively. Exposing specimens to a magnetic field increased compressive strength, with improvements up to 60.36 % for 7-day and 48.02 % for 28-day concrete at 1 T. Incorporating silica sand and micro silica in concrete positively impacts compressive strength under a magnetic field. Silica sand enhances compatibility with additives, improving strength. However, substituting 10 % of cement with micro silica reduces strength due to decreased aggregate adherence. 7-day specimens are more susceptible to magnetic fields than 28-day specimens due to lower displacement in younger samples. This innovative method enables controlled material behavior under magnetic influence. It aims to reduce cement usage while compensating for strength reduction caused by micro silica substitution. The study also determines the minimum magnetic field needed to counteract strength decrease; the aspects which not previously explored.

Evaluation of Energy Dissipated by Non-Sintered Hwangto Concrete after Exposure to Elevated Temperatures

To reduce CO<sub>2</sub> emissions, the construction industry is applying various mineral admixtures to reduce cement usage. This study evaluates the mechanical properties of non-sintered Hwangto concrete, which is an eco-friendly mineral admixture, after exposure to high temperature. The evaluation is performed for four variables: unit weight, compressive strength, stress-strain behavior, and dissipated energy, under six target temperatures ranging from room temperature to 700 °C. Experimental results show that non-sintered Hwangto degrades the mechanical properties of concrete at room temperature but exhibits better residual mechanical properties compared with cement after being exposed to high temperature.

Effect of glass waste powder and date palm seed ash based sustainable cementitious grouts on the performance of semi-flexible pavement

Cement plays a pivotal role in the production of semi-flexible pavement (SFP), however, it contributes to 8 % of global carbon dioxide emissions. Consequently, reducing cement usage in grout production for porous asphalt mixtures is highly desirable to mitigate the overall carbon footprint. Additionally, the substantial generation of agricultural, industrial, and hazardous waste often ends up in environmental disposal without recycling. This research aims to repurpose glass waste powder (GWP) and date palm seed ash (DPSA) as partial substitutes for cement in SFP, aiming to curtail environmental pollution from cement production, decrease costs, and enhance waste and landfill management. Novel cement grouts were formulated by partially replacing Portland cement with GWP and DPSA at varying ratios (10 %, 20 %, and 30 %). These grout blends were assessed for flow characteristics and compressive strength. Furthermore, SFP samples were prepared by integrating 5 % styrene-butadiene-styrene (SBS)-modified bitumen into a porous asphalt structure, subsequently filled with predefined cement grouts. Comparative analysis of compressive strength, Marshall stability, skid resistance, and moisture damage resistance indicated that SFP specimens modified with GWP and DPSA exhibited superior performance over conventional counterparts. Optimal results were achieved with a combination of 20 % GWP and 10 % DPSA replacement ratio, yielding denser microstructure, enhanced skid resistance, and improved adhesion and tensile strength, thereby enhancing overall SFP performance.