Improvement In Compressive Strength Research Articles

Utilization of Industrial Waste Casting Sands as Sustainable Building Material in Autoclaved Aerated Concrete Products

Autoclaved aerated concrete (AAC) is a building material with low density compared to traditional and structurally lightweight concrete. In addition to being very light, it is frequently preferred in many different areas, especially in external walls, floor slabs, lintels, roof slabs and panel elements of buildings, since it offers good heat and sound insulation. When the AAC production process is evaluated in terms of energy requirement, it has high environmental sensitivity compared to traditional concrete and brick processes. Since environmental sensitivity has become more important today, it was desired to evaluate the waste casting sands (WCS) generated in metal casting companies within the scope of the study. In this study, the usability of WCS as an alternative instead of silica sand used in AAC production was investigated. For this purpose, WCS was provided by 3 different casting companies. The usability potential of WCSs at 30% was examined and the quality of AAC was compared with reference castings. The fineness potentials of WCSs were compared by grinding in a disc mill. First of all, X-ray fluorescence spectrometry (XRF) and grain size analyses were performed on WCSs. 150x150x150 mm3 sized AAC laboratory samples were produced. The produced AAC samples were kept in the oven at 60°C until they set and then cured in an autoclave for approximately 10 hours. After the curing process in the autoclave, analyses such as compressive strength analyses and dry unit weight measurements were performed on the samples, and in addition to these analyses, they were subjected to visual examinations. Mechanical analyses were performed by replacing the WCS, from which positive results were obtained, at 5 different substitution ratios of 5, 10, 15, 20, and 30% by weight. From scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses, it was determined that tobermorite structures were formed. From thermal analyses, it was observed that the thermal stability of the samples produced with WCS was better. When the results were evaluated in general, it was found that up to 30% WCS could be included in the AAC production system. In addition, an increase in compressive strength values occurred. The improvement in compressive strength also showed that WCS could be a good alternative source to silica sand.

Enhancing sand control in loose reservoirs: nanofluid application

This paper introduces a novel epoxy-based nanofluid for sand control in loose reservoirs prone to sand production issues. The nanofluid combines epoxy resin with carbon nitride nanoparticles and a gas generating agent to enhance both compressive strength and permeability. Experimental studies demonstrate significant improvements in compressive strength and permeability, indicating the potential effectiveness of the nanofluid in consolidating sand in oil and gas reservoirs. Sandpack flooding experiments under reservoir conditions reveal promising results, suggesting the nanofluid's suitability for various permeability characteristics. These findings propose the epoxy/g-C₃N₄ nanofluid as a promising solution for sand consolidation, warranting further research and field testing for practical application in reservoir engineering. Keywords: sand control; epoxy nanofluid; chemical sand consolidation; graphitic carbon nitride; compressive strength enhancement; permeability control.

Design and mechanical properties analysis of drill pipe’s joint thread with unequal taper under complex loads

The design of drill pipe joint thread with unequal taper is proposed to investigate the fracture failure of the API NC38 used in the drill pipe joint of the SU36-8-4H2 well. The effect of changes in thread taper on the stress distribution and mechanical properties of drill pipe joints is analyzed and compared with the API standard thread to determine the optimal thread structure with unequal taper. The results reveal highly concentrated stress at the last engaged thread root of API NC38 single-shoulder thread (SUT) may cause early yield failure of the joint threads. Adjusting the unequal taper of the pin thread mitigates uneven stress distribution in NC38 single and double-shoulder threads and enhances connection strength, particularly for SUT-II and DUT-I. However, altering the box thread’s unequal taper modifies the stress concentration slightly in NC38 single and double-shoulder threads. This offers limited tensile and compressive strength improvement. The maximum Mises stress value of SUT-II is reduced by 56.69% compared to SUT. The maximum Mises stress value of DUT-I is reduced by 34.87% compared to NC38 double-shoulder joint thread (DUT). This design approach can guide the optimization of other API threads and enhance joint strength for non-API and specialized taper threads.

Machine Learning and Regression Models for Evaluating Ultimate Performance of Cotton Rope-Confined Recycled Aggregate Concrete

This study investigates the use of cotton ropes (CRs) as a sustainable and cost-effective substitute for synthetic fiber-reinforced polymers for concrete confinement, offering significant environmental benefits such as lower CO2 emissions and reduced energy consumption. The work evaluates the effectiveness of CR strips for confining concrete, including scenarios with recycled concrete aggregates (ReCA). Compressive strength improvements varied among specimens, with Specimen I-3F showing a 140.52% increase and Specimen II-3F achieving a 46.67% improvement. Strip configurations for Type I recycled aggregate concrete (RAC) outperformed full wraps on Type II RAC, exemplified by Specimen I-3S’s 84.51% improvement. Ultimate strain enhancements ranged from 915% to 4490.91%, driven by the significant rupture strain of cotton rope confinement. For Type I RAC, complete wrapping significantly outperformed strip configurations by 56%, 50%, and 32% in ultimate strength improvement for 1, 2, and 3 layers, respectively. The confinement ratio, varying from 0.10 to 0.70, greatly influenced the compressive behavior, with compressive strength normalized by unconfined strength increasing consistently with the confinement ratio. A minimum confinement ratio of roughly 0.40 is required to achieve an increasing second part in the compressive behavior. The initial parabolic branch was modeled using Popovics’ formulation, revealing an elastic modulus approximately 20% lower than ACI 318-19 predictions. The second branch was described using a linear approximation, and nonlinear regression analysis produced expressions for key points on the idealized compressive curve, enhancing model accuracy for CR-confined RAC. The R2 values for the nonlinear regression analysis performed on experimental results were greater than 0.90. This study highlights the effectiveness of neural network expressions to predict the compressive strength of CR-confined concrete. A strength reduction (ratio of full wrap and strip wrap height CRs) factor of 0.67 was proposed and used for strip-wrapped specimens. It was seen that the neural network models also predicted the compressive strength of partially wrapped specimens with reasonable accuracy using the strength reduction factor.

Utilization of graphite tailings and coal gangue in the preparation of foamed ceramics

AbstractTo enhance the effective utilization of graphite tailings and coal gangue (CG), both considered typical industrial solid waste materials, we synthesized foamed ceramics incorporating these materials. The optimization process led to improvements in compressive strength, water absorption, and thermal conductivity by regulating critical parameters, including the proportions of SiC and Na2O, as well as the duration of ball milling. Employing techniques such as X‐ray diffraction, thermogravimetric analysis, and differential scanning calorimetry, we investigated the phase composition, high‐temperature reactions, and microstructural characteristics of the foamed ceramics. The incorporation of graphite tailings (GT) facilitated the formation of a rich network of pore structures and amorphous glass phases, which enhanced the lightweight nature, mechanical strength, and thermal insulation properties of the foamed ceramics. By analyzing the GT content as a variable, we determined that the G50C40 (GT:CG:potassium feldspar = 40:50:10) sample exhibited optimal performance overall. Under these experimental conditions, the foamed ceramic demonstrated a bulk density of 0.749 g/cm3, a compressive strength of 12.37 MPa, a thermal conductivity of 0.21 W/(m·K), and a water absorption rate of 0.79%. Therefore, it is posited that GT possesses considerable potential to broaden the application spectrum of foamed ceramics within the domain of building insulation materials.

Influence of Repeated Wetting-Drying Process on Strength of Cement Admixed Soil Improved by Natural Liquid Latex Rubber

This study investigated the impact of wet-dry cycling on the unconfined compressive strength of compacted cement-soil mixed with latex rubber. The objective was to simulate the fluctuating moisture conditions in the soil caused by alternating rainy and dry seasons over multiple years. The experiments compared cement-soil samples to rubber-cement-soil samples. The amount of cement used was equivalent to 8 percent of the dry soil mass, while the latex emulsion content was 8 percent by cement mass. The wet-dry cycling process was performed on the samples cured for 28 days. The results indicated that the rubber-cemnet-soil samples consistently exhibited enhanced compressive strength compared to the cement-soil samples. During the initial two cycles of the wet-dry process, the rubber-cement-soil samples demonstrated a greater rate of compressive strength improvement than the cement-soil samples. This indicates that the rubber particles contribute to strengthening the soil during the wetting-drying process. It is worth noting that the rate of compressive strength increase for both sample sets becomes comparable after the second cycle of the wetting-drying process.

Recycled coarse aggregate concrete and its application in CFRP reinforced concrete beam

This paper deals with performance of concrete by using recycled coarse aggregate (RCA) to replace 30%, 50%, and 70% of natural coarse aggregate. Three concrete types were studied: Group A using RCA with 10% of silica fume (SF) addition by weight of cement, Group B using RCA with 30% of fly ash (FA) substitution by weight of cement, and the control concrete without RCA, SF, FA. Group A demonstrated a considerable improvement in compressive strength whereas group B exhibited a noticeable reduction, in comparison to the control concrete. Secondly, three reinforced concrete beams, representing three concrete types, strengthened with carbon fiber reinforced polymer (CFRP) sheet were tested under a three-point bending fixture. All the flexural parameters of the tested beam, including load bearing capacity, deflection capacity, stiffness, ductility, and crack patterns were evaluated and discussed. Finally, an analytical model was suggested to estimate moment and shear resistance of the beams.

The Influence of Planning and Architectural Styles on the Sustainability of the City of Kumasi, Ghana

The city of Kumasi that was once dubbed the ‘Garden City of West Africa’ was founded in the late 17th century and served as the seat of government for the medieval Greater Asante Union. It later served as a commercial hub for the British Colony after undergoing massive transformation in the first two decades of the 19th century. Post-independence, the city went through various urban planning projects that mostly targeted social development. The architecture of Kumasi has also been changing through different periods of its history. This article examines the relationship between the evolution of the city of Kumasi through urban planning and architecture and the general sustainability in construction. The results show that there is massive depletion of the green belt in Kumasi. Moreover, contemporary architecture uses fewer passive designs for indoor climate control and less local materials for construction. Use of technology for improvement of local materials compressive strength and integration of renewable energy sources in architecture are recommended as course of action.

Experimental Evaluation of Concrete Blended with Eco-Friendly Bio-Sulfur as a Cement Replacement Material.

Bio-sulfur (BS), extracted from landfill bio-gas via microbial methods, was examined herein as a potential cement replacement material. The study developed five modified BS variants through limestone incorporation processes (sulfur-to-limestone ratios of 1:0.5, 1:1, 1:1.5, 1:3, and 1:5). The study revealed that modified BS with higher limestone ratios demonstrates significant workability and strength reductions of over 50% with increased content, leading to the adoption of a sulfur-to-limestone ratio of 1:1. The concrete specimens exhibited compressive strength improvements of up to 12% with increased BS content, while the UPV showed proportional increases with increased BS content that remained independent of the water/binder (W/B) ratio. Statistical analysis confirmed significance with p-values below 0.05. XRD analysis identified initial cement hydrate peaks at 3 d that evolved into distinct Mg-S hydrate and Ca-Al-S hydrate formations in the BS-containing specimens by 28 d.

Enhancing recycled aggregates concrete (RAC): pre-soaking treatment in micro and nano pozzolanic solutions for superior performance

The use of recycled materials in construction is a key strategy for sustainable development and reducing landfill space. Recycled concrete aggregates (RCA) are commonly used but often result in lower concrete quality, primarily due to weaknesses in the interfacial transition zone. To address this, aggregates were pre-soaked in various pozzolanic solutions, including micro-silica, micro-zeolite, nano-silica, and nano-montmorillonite. Mechanical tests (compressive strength, modulus of elasticity) and durability tests (drying shrinkage, sulfate attack, half-cell corrosion potential, electrical resistance) were performed to evaluate performance improvements in both short and long terms. Results showed an improvement in compressive strength for most treatments after 28 days, with nanosilica-treated concrete showing the highest increase (12.4%). Durability tests revealed the best performance against sulfate attack for concrete with aggregates treated in nano-montmorillonite and nano-clay solutions, with reductions in compressive strength of 19.39% and 18.19%, respectively, after 10 months. Microstructural analysis confirmed that pre-soaking aggregates in pozzolanic solutions positively affected both mechanical and durability properties. Zero-dimensional pozzolans showed short-term benefits, while two-dimensional pozzolans, like montmorillonite, had more significant long-term effects, offering a promising solution for improving recycled concrete’s overall performance, especially in harsh environmental conditions and challenging construction environments.

Mechanical properties of Polypropylene Fibre reinforced concrete for M25 mixes.

This paper focuses on experimental study in the behaviour of polypropylene fibre reinforced concrete. The polypropylene (PP) fibres were mixed into the concrete in the form of reinforcement into the concrete with uniform orientation of the fibres. By adding polypropylene(PP) fibre in concrete the crack formation reduces. Polypropylene (PP) fibre is also heat resistant that is advantageous over polyethylene fibre.The tests on the concrete were conducted after adding polypropylene (PP) fibres into the concrete in different contents, i.e.; 1.5%, 1.75%, 1.85% of the cement mass. Polypropylene is one of the cheapest and abundantly available polymers. Chemical inertness makes the polypropylene fibers resistant to most chemicals. In this paper the relationship between cube compressive strength and cylinder split tensile strength for conventional and polypropylene fibre reinforced concrete were established and compared with standards. The study prompted the substantial improvement in compressive and tensile strength for concrete mixes reinforced with polypropylene fibres. Use of polypropylene (PP) fibre and E waste in M25 concrete increases the flexible strength, prevents the crack an also increases the impact strength of concrete.Positioned on test results obtained 1.5% of polypropylene (PP) fibre addition found to be optimal percentage of polypropylene (PP) fibers. The optimal percentage of polypropylene (PP) fibre 1.5% is used in the experiment. M25 grade of concrete achievement is assessed with respect to slump test, compressive strength, split tensile strength and flexural strength.

Polymer Concretes Based on Various Resins: Modern Research and Modeling of Mechanical Properties

This review is devoted to experimental studies and modeling in the field of mechanical and physical properties of polymer concretes and polymer-modified concretes. The review analyzes studies carried out over the past two years. The paper examines the properties of polymer concretes based on various polymer resins and presents the advantages and disadvantages of various models developed to predict the mechanical properties of materials. Based on data in the literature, the most promising polymers for use in the field of road surface repair are polymer concretes with poly(meth)acrylic resins. It was found that the most adequate and productive models are the deep machine learning model—using several hidden layers that perform calculations based on input parameters—and the extreme gradient boosting model. In particular, the extreme gradient boosting model showed high R2 values in forecasting (in the range of 0.916–0.981) when predicting damping coefficient and ultimate compressive strength. In turn, among the additives to Portland cement concrete, the most promising are natural polymers, such as mammalian gelatin and cold fish gelatin, and superabsorbent polymers. These additives allow for an improvement in compressive strength of 200% or more. The review may be of interest to engineers specializing in building construction, materials scientists involved in the development and implementation of new materials into production, as well as researchers in the interdisciplinary fields of chemistry and technology.

Influence of silica fume on pore structure, mechanical properties and carbon emission of reactive powder concrete prepared by ice crystal homogenization technology

Under ultra-low water-to-binder ratio conditions, the liquid-bridge effect between powders seriously restricts the development of reactive powder concrete (RPC). Ice crystal homogenization technology fundamentally solves the liquid-bridge problem between powders. However, high carbon emissions still constrain the application of RPC. This paper introduces an innovative RPC material incorporating silica fume (SF) as a supplementary cementitious material to solve environmental concerns and alleviate powder aggregation challenges based on the ice crystal homogenization technology. Experimental results show that there was a significant improvement in compressive and flexural strengths observed, particularly in RPC material containing 15% SF, which exhibited the most notable enhancements: a 19.7% increase in compressive strength to 296.3MPa and a 23.6% increase in flexural strength to 43.8MPa. Moreover, the optimized microstructure was reflected in a substantial reduction in water absorption rate and cumulative pore volume by 44.7% and 54.4%, respectively. Besides, RPC incorporating 15% SF achieved the lowest carbon emissions efficiency, with carbon emissions efficiency could be reduced by 79%~93% compared with conventional UHPC. In conclusion, the use of SF and ice crystal homogenization technology in RPC provides the great potential for developing sustainable construction materials and promoting carbon reduction strategies.

Redispersible Acrylic Ester Polymers: Effect of Polymer Property Changes Due to Polymerization Method Modification and Functional Additives on the Performance of Polymer Cement Mortar.

This paper presents an experimental study aimed at improving the performance of polymer cement mortar by evaluating the properties of acrylic ester redispersible polymers, synthesized using a change in polymerization method from emulsion monomer to monomer dropwise addition methods, along with the use of a functional additive in the form of a foaming agent. To achieve the research objectives, a polymer with a glass transition temperature of -11 °C was synthesized by fixing the monomer ratio, particle-size distribution, and glass transition temperature, and the physical properties of the polymer cement mortar were assessed. The results showed that polymers synthesized using the modified polymerization method increased elongation at break and possessed a 35% smaller average particle size. The use of the foaming agent also resulted in enhanced tensile strength. The polymer cement mortars made with these respective polymers demonstrated improvements in compressive strength 11~25%, flexural strength 53~77%, bond strength 78~113%, volumetric changes 65~88%, and water absorption 30~70%. These findings suggest that changes in the polymerization method and the incorporation of functional additives influence the average particle size and air entrainment control properties of the polymers, thereby positively impacting the performance of the cement hydrates.

Investigation on novel ultralight weight thermally insulated fireproof composite

Abstract This study highlights the performance of ultra-lightweight fireproof composite. Polyacrylonitrile based carbon fiber (CF) has been reinforced in Polyetherimide (PEI) polymer to develop the composite. The Surfac2e of CF and PEI film was modified by low-pressure plasma to improve the bonding strength between matrix and reinforcement. The polymeric composite was fabricated by compression molding with a pressure of 2 bar, temperature of 380 °C and holding time of 30 min. CF/PEI composite was used to make a hybrid composite by layering of silicone foam in between the layers. The hybrid composite was exposed to a Bunsen burner under sustained flame for a duration of 10 min. The composite panel’s flame-facing side reached 676.2 °C after 10 min of fire exposure, while the temperature on the other side only reached 58.2 °C. The fabricated hybrid composite was exposed to very low temperature in order to test its ability of thermal insulation under extreme cold temperature. Over the specific period of testing, the temperature of the dry ice decreased from 25 °C to −3.1 °C. After exposure to fire, only minimal loss of material was observed. The hybrid composite of carbon fiber and PEK film, sandwiched between silicone foam, exhibits excellent fire resistance due to its high limiting oxygen index. This composite is considered to be among the best thermally insulating and fire-resistant materials. Thermogravimetric analysis of carbon fiber and PEI-Carbon fiber composite was performed to determine the optimal processing temperature of compression molding for the composite, upon heating, it showed a modest weight decrease of 6.053%. The composite shows a significant improvement of impact resistance, compressive strength and thermal stability. A simulation model was developed under Ansys fluent software for both heating and cooling. The analysis of developed model also shows similar results.

Hardening properties, water resistance and associated micro-mechanism of nano-modified calcium sulphoaluminate cement

Calcium sulphoaluminate cement (CSA) is considered a sustainable alternative to traditional Portland cement to reduce CO2 emissions. To further improve the hardening properties and water resistance of CSA and advance its extensive special engineering application, nanoparticles including nano-SiO2 (NS), nano-MgO (NM) and nano-Al2O3 (NA) were used as nano-modifiers for CSA. The effects of nanoparticles dosage on the setting time, compressive strength and water resistance of nano-modified CSA were experimentally evaluated, and the micro-mechanisms were also clarified by conducting X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TG) tests. The results showed that incorporating nanoparticles into CSA obviously shortened the initial and final setting times. The appropriate addition of nanoparticles effectively enhanced the compressive strength of CSA, and the optimum dosages of NS, NM, and NA were respectively determined to be 0.5 %, 1.0 %, and 0.5 %. Water immersion decreased the bonding strength of CSA, and adding nanoparticles can effectively weaken this water-induced deterioration effect. Under water immersion environment, the optimum dosages of nanoparticles would be increased to obtain the highest residual water immersion strength and minimum strength loss rate. The generation of ettringite was mainly responsible for the compressive strength and water resistance improvements of nano-modified CSA. The hydration process of nano-modified CSA was clarified and the corresponding micro-mechanism model was proposed. Furthermore, the benefits and challenges of using nano-modified CSA were also analyzed, advancing its widespread application in rapid repair of special engineering.

Performance and life cycle of Portland limestone cement mixes admixed with gypsum

In this study, the life cycle and performance of normal concrete containing 35% limestone and 2% gypsum made in different ratios of water to binder (w/b) were examined. Its cost and CO2 emissions were found to be 13% and 35% lower compared to the control concrete. However, because of the greater replacement of cement with limestone filler, there is a reduction in its workability, the development of heat and strength, and the penetration resistance of water and chloride ions, especially in the early ages. The addition of gypsum marginally improved these concrete properties, but its quantity should be limited to 2% by weight of the binder. The use of gypsum beyond this limit led to a significant decrease in the properties of concrete. Anorthite, a calcium aluminosilicate mineral, was found in this concrete, and its fractured morphology was found to be more occupied with unreacted angular limestone particles. This low-carbon concrete showed an improvement in compressive strength with decreasing w/b ratios. The limestone reserve in India is abundant and spread evenly across its length and depth, and its use as the main replacement for cement in normal strength mixes would greatly reduce the impact of CO2 on the environment.

Mechanical and microstructural characteristics of Al-Li2099-graphene MMCs for aerospace applications

ABSTRACT Aluminium-Lithium (Al-Li) alloys are known for its properties that are superior to conventional ones. The inclusion of graphene reinforcements to the metal matrix improved strength, stiffness, density reduction, tensile properties, wear, creep, and fatigue resistance. This study examined the combined result of graphene nanoparticles (GNP) and the Al-Li2099 alloy with an ultrasonic-aided stir-casting process. The nano-particulate metal matrix composites with various weight percentages (wt. %) of GNP were fabricated and investigated for physical, mechanical, and microstructural properties. The nanocomposites’ mechanical properties were examined in detail, and significant improvements in hardness, tensile, and compressive strength were observed with higher wt. % of GNP. Theoretical and empirical densities were measured, revealing that the nanocomposite’s densities decrease with the increase in wt. % of nano-reinforcements. Material characterisation of the composites was carried out using XRD, EDAX, SEM, and Fourier-Transformation Infrared Spectroscopy (FTIR). SEM and EDAX confirmed the presence of GNP particulates in the matrix microstructure and elemental composition. The XRD results confirmed the presence of GNP particulates in the Aluminium Alloy (AA) 2099 and the composite, and no other intermetallic elements were detected. The results demonstrated that the GNP addition to the AA2099 significantly enhanced the mechanical and microstructural characteristics of the nanocomposite.

A concise strategy for enhancing the performance of bio-based polyurethane aerogels using melamine-modified sodium alginate via Aza-Michael addition reaction

Bio-based waterborne polyurethane (PU) has garnered significant attention as a sustainable alternative petroleum-derived counterpart, offering environmentally friendly alternatives. In this work, a new approach is proposed to fabricate two kinds of composite aerogels of lowly/highly melamine-modified sodium alginate (SAML/SAMH) with methacrylate-terminated PU (SAML-PU and SAMH-PU) through dynamic covalent cross-linking via Aza-Michael addition reactions. We aim to improve the poor compatibility of polysaccharide and PU associated with traditional blending methods and impart the resulting aerogels with good biodegradability, compressive strength, thermal insulation, flame-retardant, and self-healing. Comprehensive characterizations, including Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy collectively demonstrate the successful derivatization of alginate and the effective synthesis of the Aza-Michael addition copolymer involving derivate alginate and PU. Substantial improvements in compressive strength and thermal properties are realized at comparable densities. Higher compressive strength, higher decomposition temperature and lower thermal conductivity are significantly achieved for SAML-PU (0.35 MPa, 410 °C and 0.024 W/m/K at 0.13 g/cm3) and SAMH-PU (0.58 MPa, 427 °C and 0.022 W/m/K at 0.12 g/cm3) compared to pristine PU foams (0.15 MPa, 330 °C and 0.031 W/m/K at 0.15 g/cm3). Additionally, molecular simulations of the Aza-Michael addition reaction and finite element simulations of aerogel thermal-insulation properties are conducted to corroborate experimental results. Notably, the dynamic polymers of SAML-PU and SAMH-PU exhibited excellent self-healing, recycling, biodegradability, and flame-retardant attributes. The elucidated preparation methodology and the exceptional performance and versatile applications of sodium alginate-based PU aerogels suggest a promising trajectory for future research endeavors and industrial implementation.

INFLUENCE AND PREDICTION OF SINTERED AGGREGATE SIZE DISTRIBUTION ON THE PERFORMANCE OF LIGHTWEIGHT ALKALI-ACTIVATED CONCRETE

The most effective method for mitigating the adverse environmental impacts of traditional concrete involves substituting cement and natural aggregate with waste and byproduct resources. Utilizing sintered lightweight aggregate (fly ash) in geopolymer concrete emerges as an efficient solution for managing and disposing of significant amounts of fly ash. The influence of sintered aggregate size distribution on the performance of alkali-activated concrete, focusing on compressive strength improvement. The study employs sintered fly ash aggregate (SFA) as coarse aggregate, aiming to optimize packing density through proper particle distribution. The highest compressive strength is achieved with a mix featuring 75% 4-8mm and 25% 8-12mm SFA. Regression-based strength models are developed, exhibiting good alignment with conventional concrete models. Thin section techniques reveal enhanced aggregate-matrix interaction due to the porous structure of SFA. The study emphasizes the potential of SFA in geopolymer concrete for sustainable construction. Lightweight geopolymer concrete, owing to its lower density, significantly reduces the overall structural load.