Compressive Strength Research Articles

A comparative assessment of geotechnical performance, cost and carbon footprint of expansive soil treated with cement, lime and fly ash

ABSTRACT Chemical stabilisation enhances strength and reduces the swell characteristic of expansive soils, and cement, lime and fly ash (FA) have been used as stabilisers. Currently, there is a scarcity of studies addressing the mix optimisation of expansive soil stabilised with cement, lime, and FA, considering factors such as strength, swell characteristics, cost, and emissions. Thus, the objective of this research is to develop an optimal mix for stabilising expansive soil using cement, lime, and FA, based on these parameters. The samples were stabilised with 2%–12% cement, 1%–6% lime and 5%–30% FA, and testing including unconfined compressive strength (UCS), swell pressure and California bearing ratio (CBR) were conducted. Utility analysis was undertaken by using Multi-Attribute Utility Theory (MAUT) incorporating UCS, cost/UCS, swell pressure, swell percent, and emissions as key parameters. The findings revealed that UCS of the cement stabilised samples increases with the cement content, while the optimum lime and FA contents based on UCS were 3% and 15% respectively. The swell pressure values of cement, lime and FA stabilised soils reduced by 11.6%–35.9%, 11.6%–22.8% and 45.0%–65.6%, respectively. Overall utility analysis revealed that 15% FA stabilised mix is the optimum mix in terms of strength, swell, cost, and emission.

Machine learning based prediction of compressive strength in roller compacted concrete: a comparative study with PDP analysis

Machine learning based prediction of compressive strength in roller compacted concrete: a comparative study with PDP analysis

Enhancing the water resistance and dimensional stability of wood through microwave treatment and impregnation with oxidised paraffin emulsion

ABSTRACT Wood is a high-performance renewable material, but its hydrophilicity seriously affects its durability and economic value. To address these issues, a new method to enhance the water resistance of wood by impregnating microwave-treated wood with the oxidised paraffin emulsion is proposed. This study investigated the effects of the pre-microwave moisture content of wood and the surfactant content in the oxidised paraffin emulsion on the weight percent gain, penetration degree, contact angle, water absorption, as well as the dimensional stability and mechanical property of the treated wood. After modification, the hydrophobicity and dimensional stability of the wood were improved, with the maximum initial contact angle of the impregnated specimens reaching 135°, and the anti-swelling efficiency for 360 h being 17%. The lowest water absorption of the impregnated specimens at 960 h was achieved at a pre-microwave moisture content of 15% and a surfactant content of 60%, resulting in a reduction of 55% compared to the control. In addition, the impregnation treatment had little effect on the compressive strength parallel to the grain of the wood. This study provided a new theoretical basis for waterproof protection of wood.

Different machine learning approaches to predict the compressive strength of composite cement concrete

Different machine learning approaches to predict the compressive strength of composite cement concrete

Optimizing recycled aggregate concrete performance with chemically and mechanically activated fly ash in combination with coconut fiber

As a matter of fact, although RCA is inferior to that of NA (natural aggregate) in terms of performance, RCA is currently being used extensively in concrete production as a sustainable solution due to global increasing construction waste. To overcome these limitations, several mechanisms and supplementary cementitious materials (SCMs) have been investigated in the recent past. This study investigates the combined effect of natural fiber coconut (0%, 0.5%,1%,1.5% and 2%) and activated fly ash (mechanically and chemically) on performance of recycled concrete aggregate (RCA). Four concrete compositions were studied: a control group with varying RCA percentages and no fly ash, second group with 30% inactive fly ash, third group with 30% mechanically activated fly ash, and a fourth group with 30% chemically activated fly ash. The findings revealed that the addition of 30% chemically activated fly ash with 1.5% CF increased compressive strength by 25%, tensile strength by 17% for 100% RCA mix, While strength losses for the same mix are 7.18% after one month and 22.14% after three months of acid exposure. Scanning electron microscopy further validates the enhanced packing density and effective crack filling in the optimized mixes, highlighting their superior performance. This approach holds significant potential for advancing sustainable development pathways in high-performance structural concrete, particularly in regions prioritizing green building solutions.

Data driven design of ultra high performance concrete prospects and application

Ultra-high performance concrete (UHPC) is a specialized class of cementitious composites that is increasingly used in various applications, including bridge decks, connections between precast components, piers, columns, overlays, and the repair and strengthening of bridge elements. The mechanical and durability properties of UHPC are significantly influenced by factors such as low water-to-binder ratios, the inclusion of supplementary cementitious materials (SCMs), and fiber reinforcement. Machine learning (ML) has been employed to predict the performance of UHPC and optimize its mixture designs by using various raw materials. This study first provides a comprehensive review of ML applications in UHPC, focusing on predicting workability, mechanical, and thermal properties. The use of data crossing, generative AI, physics-guided ML models, and field-applicable software are explored as practical directions for future research. This study also develops ML models to predict the compressive strength of UHPC by using a database containing 1300 data-records. The influence of various input variables is evaluated using SHapley Additive exPlanations (SHAP), revealing that chemical compositions have relatively minor impacts, given the material types used. By excluding insignificant variables, the models enhance both efficiency and accuracy in predicting strength. This advancement facilitates optimized material design and performance prediction while reducing the experimental workload required to inform ML models. Adding more diverse data to the database could further enhance the prediction performance and generalizability of the proposed ML models.

Effect of blending GGBS and silica fume on the mechanical properties of geopolymer concrete

This study investigates the mechanical properties of geopolymer concrete made with ground granulated blast furnace slag (GGBS) and silica fume (SF) as binders. The influence of varying binder proportions and sodium silicate-to-sodium hydroxide (SS-to-SH) ratios of 1.5 and 2.0 in the alkali-activated solution was examined. Experimental tests evaluated slump, compressive strength, modulus of elasticity, and splitting tensile strength at 1, 7, and 28 days. Increasing SF content up to 50% in the binder with a solution ratio of 1.5 improved the 28-day compressive strength by 50% compared to mixes made solely with slag. However, further increase in SF reduced splitting tensile strength and compressive strength by 79 and 56%, respectively, at 28 days. Increasing the solution ratio from 1.5 to 2.0 enhanced compressive strength for slag-dominant mixes by up to 63% but reduced strength for SF-rich mixes by up to 87%. The highest modulus of elasticity, 18.7 GPa, was achieved with slag-only binders and a solution ratio of 2.0, marking a 240% increase over its counterpart mix with a lower solution ratio. Equal GGBS and SF blends improved splitting tensile strength compared to SF-rich mixes but were surpassed by GGBS-rich mixes in terms of overall structural performance.

Strength and Durability of Concrete with Quarry Dust as a Sand Substitute

Abstract Growth has increased demand for natural sand, producing depletion and environmental difficulties. Quarry dust—a byproduct of rock crushing—is studied as a sustainable substitute for natural sand in M40-grade concrete. Significant effects on workability and compressive strength at various replacement weight percentages of 10%, 20%, 30%, and 40% are the main focus. According to IS 10262-2019 and IS 516-1959, 45 concrete samples were cast, cured, and evaluated at 7, 14, and 28 days. Replacing up to 20% of fine aggregate with quarry dust boosts compressive strength. The peak strength after 28 days was 46.35 MPa, significantly less than the average mix's 47.23 MPa. Performance diminishes beyond this threshold, with strengths decreasing to 35.21 MPa at 30% replacement levels and 34.04 MPa at 40%. The results show that quarry dust can replace natural sand due to its similar physical and chemical properties. Use of recycled industrial waste in concrete saves sand supply, decreases environmental harm, and supports circular economy. This study revealed that sustainable concrete production at 20% replacement may retain durability and strength. Quarry dust's environmental benefits may help the building industry become greener and more resource-efficient. Keywords: M40 Concrete Mix, Quarry Dust, Fine Aggregate Replacement, Sustainable Construction, Compressive Strength.

Behavior of Ferrocement Reinforced Concrete Beams Incorporating Waste Glass Exposed to Fire

This study is an experiment that looks at what happens when 18 supported reinforced concrete beams with waste glass inside them are put on fire. All the supported beams were tested under a three-point load. We classified the beams into three groups based on the glass-to-sand replacement ratio. Two sand replacement ratios (10% and 20%) were considered and compared with the control beams (without replacement). Two periods of burning were studied to investigate the mechanical properties of ferrocement and the behavior of simply supported beams. We considered a temperature of 550 °C and gradually increased the burning to reach this degree. Mode failure, mechanical properties, and load–deflection were present in this study. According to this study and its results, it seems that approximately all mode failures were compound flexural and shear failures. The flexural and compressive strength of replacing sand with glass concrete leads to an improvement in the flexural behavior of the reinforced concrete beam incorporating waste glass (brittle failure) that happened when burning the beam element without sand replacement glasses. The replacement ratio (10%) is the best value of the replacement ratio of the glasses; the compressive strength increased by about 10% to 29% by the replacement ratio. When replacing 10% of the sand with glasses, the ratio increases from 1% to 16%, but the compressive strength decreases from 20% to 51% when the burning time increases from one hour to an hour and a half. When 10% of the sand is replaced by glasses by weight, the first crack load capacity goes up by about 8% for one hour of burning and by 16% for one hour and a half of burning compared to beams that are not burning. The ultimate load capacity also goes up by about 17.5% for one hour of burning and by 23.5% for one hour and a half of burning compared to beams that are not burning. Otherwise, sand replacement was 10% by glasses; by weight, the ultimate load strength increased about 6% when the burning was one hour and 12% when the burning was one hour and a half compared with the beams without burning for the same phase.

Consideration on Application of Nondestructive Test to Estimate In-Situ Compressive Strength of Concrete: A Case Study

To comprehensively explore the utility of non-destructive tests (NDT) results for structural diagnosis, this study collected NDT results and core compressive strength test results from aged bridges. Girders and slabs were obtained from seven such bridges, and after sectioning, rebound hardness test (RHT) or ultrasonic pulse velocity test (UPVT) were conducted alongside coring. The standard equations for estimation in South Korea were applied and a comparison between core strength and strength estimated using NDT results was conducted. In addition, the relationship between the static modulus and core specimen strength was determined to assess the soundness of the concrete cores, a factor that influences NDT signals. Based on the experimental results, this study deliberates on the practical applications of NDT results in structural diagnosis. A protocol for calculating the characteristic in-situ compressive strength using NDT results without coring was proposed and statistically validate this protocol via a probabilistic simulation.

Characterisation of the Mineralogy, Durability and Physical Properties of Two Earth Mortars: An Experimental Study

Abstract Mortars composed of a blend of earth and cement are widely employed in masonry, particularly in the construction of earth blocks. This study is primarily focused on investigating the influence of mineralogical and chemical constituents on the mechanical characteristics of two types of mortars. Furthermore, we have assessed the water absorption coefficient of these mortars, which vary in cement content, with the aim of enhancing their longevity. The findings reveal a significant enhancement in compressive strength, attributed to the interaction between calcium hydroxide in cement and clay minerals containing silico-aluminous compounds. Importantly, the incorporation of cement not only affects the macroscopic properties concerning particle size fractions but also heavily depends on the mineralogical composition, particularly the clay content. Moreover, the addition of cement results in a reduction in water absorption, whereas an increase in magnesium oxide content within the clay leads to higher water absorption rates.

Enhancing mixed recycled aggregate properties using water glass coating: optimization and performance in concrete applications

The rapid advancement of global infrastructure has resulted in a significant increase in construction and demolition (C&D) waste, raising urgent environmental issues stemming from inadequate disposal and management strategies. Recent research has focused on recycling C&D waste as mixed recycled aggregate (MRA) in concrete, majorly in developing countries, to promote sustainability. This study investigates a novel method for improving MRA characteristics by treating it with a water glass (WG) coating solution. A central composite design (CCD) model was used to identify the best treatment conditions considering WG concentration, water-to-aggregate ratio, and soaking duration as independent variables to facilitate treatment in MRA. The model’s performance was evaluated using water absorption, Los Angeles (LA) abrasion resistance, and apparent density. The microstructural analysis demonstrated that WG treatment enhanced MRA by forming calcium silicate hydrate (C-S-H) gel, which improved the pore structure and interfacial transition zone (ITZ). The optimised treated MRA was incorporated into the concrete at replacement levels of 0, 25, 50, 75, and 100% to assess workability, mechanical properties, and microhardness. The results indicated that substituting 25% of natural coarse aggregate with treated MRA led to significant enhancements in workability by 11.76%, compressive strength by 4.83%, split tensile strength by 2.94% and flexural strength by 3.43% while maintaining comparable hardness values to conventional concrete. The improvement was linked to the densification effect of the WG coating, resulting in enhanced bonding and mechanical performance. The results demonstrate a viable way to recycle C&D waste while maintaining structural integrity in concrete applications.

Numerical Analysis for Shear Strength of Composite Box Steel-Concrete Beam Transverse Intermediate to Large Openings

Abstract This research paper presents a numerical analysis of composite box steel-concrete beams with transverse intermediate to large openings, conducted using the ABAQUS program. The study focused on various parameters, including opening size, shape, location, shear span to effective depth ratio, compressive strength, and diameter of rebars, to understand their effects on the shear load capacity of the beams. The results demonstrated a strong agreement with experimental data, with a correlation ranging from 0.927 to 1.023. Key findings include Increasing the opening size from 90x90 mm to 110x110 mm and from 110x110 to 136x136 led to a 12.7% and 42.4% respectively decrease in shear load, Changing the shape of openings from square to circular decreased the shear load by 14.7% for 90 mm openings and 14.2% for 110 mm openings, while increased the shear load by 15.25% for 136 mm. Moving transverse openings closer to the loads by 126 mm reduced the shear load by 7.5% for 90x90 mm openings, 9.8% for 110x110 mm openings and 17.2% for 136×136 mm openings. The difference in shear load between the highest and lowest (a/d) ratios is 12.5% for 90×90 mm openings, 7.2% for 110×110 mm openings, and 0.8% for 136×136 mm openings. Beams with a compressive strength of 37.5 MPa showed higher shear loads compared to those with 30 MPa, with increases of slight change, and the shear load increased of slight change for beams with reinforcement (2ø25-2ø16) compared to those with (3ø16) for 90x90 mm openings, 110x110 mm and 136x136 mm openings.

Implementation of agro-industrial by-products in expansive soil amelioration: design of experiment approach

The utilization of waste residues for soil amelioration is becoming increasingly popular in the construction industry due to its potential for effective waste management and resource utilization. This practice is of utmost importance for the sustainable development of nations, as it offers both environmental protection and economic benefits. In this study, we investigate the sustainable incorporation of Design of Experiment (DOE) to optimize the use of binary additives for enhancing expansive soil. The selected binary additives for this study are calcium carbide residue (CCR) and palm oil fuel residue (POFR). A total of twenty different mix designs were prepared using various combinations of CCR, POFR, water, and soil, following the Scheffe’s DOE strategy. To evaluate the performance and effectiveness of the additives, mechanical testing, including durability and unconfined compressive strength tests, was conducted. The results showed peak values of 58% for durability and 735 kN/m2 for unconfined compressive strength (UCS). Additionally, the analysis of variance and student t-test, which are standard techniques for assessing the goodness of fit, were applied to statistically analyse the mathematical models and validate their adequacy and validity. Microstructural experiments, involving scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), were performed on the natural soil and soil treated with the optimal level of additives. The SEM analysis confirmed the formation of new compounds resulting from the incorporation of CCR-POFR mixtures, while the FTIR analysis validated the presence of different molecular functional groups in the treated soil.

Study the Effect of Waste Materials Ash (Date Seed Ash) on Expansive Soil

Abstract Expansive soils experience volumetric expansion as they absorb water, resulting in pressure being exerted on the foundation soils and causing movement of the foundation. The forces generated by these variations in volume may cause substantial damage to the buildings above them. Date seeds are the leftover material from certain facilities that make date syrup. Laboratory experiments were conducted to examine the effects of DSA work as a soil stabilizer on the expansive soil’s compressibility and expansion. Four different amounts of DSA (6%, 9%, 12 and 15%) were added to the bentonite soil to investigate the effect of DSA on bentonite soil properties. Compaction, Atterberg limits, and unconfined compression tests are selected to investigate the mechanical and swelling improvement in bentonite soil. According to test findings, adding DSA reduced bentonite soil’s plasticity and expansive index with increasing DSA ratios. The unconfined compressive strength test was conducted during three curing ages (0, 7 and 28) curing ages day, and the best results were obtained when using 9% of DSA as stabilizer materials.

Investigating the structural performance of graphene nanoparticles infused reinforced concrete

This research investigates the structural performance of reinforced concrete infused with graphene nanoplatelets (GNPs). To address the urgent need to reduce the carbon footprint of the construction industry, this study explores the potential of GNPs to enhance concrete properties, thereby decreasing the required cement quantity. Various GNP concentrations were incorporated into concrete mixes, followed by thorough testing of their mechanical and microstructural properties. Experimental results revealed significant improvements, such as compressive strength increased by up to 40%, tensile strength by 27%, and toughness by 47%. Furthermore, the incorporation of GNPs demonstrated potential CO₂ reductions of up to 446 kg per ton of cement, contributing to sustainable construction practices. SEM analysis showed improved microstructure with fewer voids and enhanced crystallinity. Additionally, GNP-reinforced concrete exhibited higher electrical resistivity and pulse velocity, indicating sound durability and reduced porosity. These findings underscore the effectiveness of GNPs in creating more tough, durable, and environmentally sustainable concrete composites.

High-Performance Polymer-derived Ceramics in LCD 3D Printing.

This study demonstrates the fabrication of high-strength, lightweight polymer-derived ceramics (PDCs) using silicon oxycarbide (SiOC)-precursor formulations with liquid crystal display (LCD) vat photopolymerization (VPP) technology. Complex geometries, such as gyroids and stochastic lattices, are successfully 3D-printed and evaluated under varying feature thicknesses and pyrolysis temperatures (800 °C and 1200 °C). Photorheology and thermogravimetric analysis (TGA) validated the efficient curing and pyrolysis characteristics of a printable precursor formulation based on vinyl methoxysiloxane homopolymer (VMM-010), which demonstrated rapid curing, low viscosity, and compatibility with LCD 3D printing, ensuring precise layering and efficient resin removal. Micro-CT scans confirmed its structural integrity and absence of voids, even in relatively thick components (≈3mm). The VMM-based PDC lattices achieved specific compressive strengths up to 9.4MPa g⁻¹ cm3, a 50-fold improvement over comparable lattices produced with a high-porosity SiOC PDC, and exceptional high-temperature stability, maintaining structural integrity after 2 h at 1500 °C. Compositional analysis revealed lower free carbon content and improved ceramic phase formation, driving the enhanced mechanical and thermal performance of the VMM-based ceramic. These findings underscore the scalability, reliability, and superior performance of VMM formulations for LCD 3D printing, offering new possibilities for high-performance ceramic applications in aerospace, automotive, and biomedical industries.

Performance of Autoclaved Aerated Concrete (AAC) Containing Recycled Ceramic and Gypsum Waste for Partition Walls Application

The normal growth population and development in big cities have caused many problems such as municipal solid waste (MSW) and noise pollution. To solve these problems, two type of eco-friendly autoclaved aerated concrete (AAC) containing recycled ceramic and gypsum waste (CGW) with different ratio (0, 5%, 10%, 15%, 20%, 25% and 30% wt) have been prepared according to American Society for Testing Materials (ASTM) C1693-09. Type one (I) is AAC containing recycled CGW as a partial replacement for sand. Type two (II) is AAC containing recycled CGW as additional material. The compressive strength of samples has been tested according to ASTM D695 by using Universal Testing Machine (UTM). The sound absorption coefficient (SAC) has been carried out by using Impedance Tube Model No: AED1000 according to ASTM E1050 at low frequency 75Hz to 500Hz. All samples showed free crack and normal colour behaviour such as grey. The compressive strength of AAC samples in the range of 6.10% to 29.88% for AAC Type I and in range of 29.27% to 45.73% for AAC type II. The maximum compressive strength was 2.13 MPa and 2.39 MPa for AAC type I and II at 15% wt and 5%wt of CGW, respectively. The maximum sound absorption coefficient was around 0.75 to 0.768 for AAC type I at frequency 500Hz. Generally, AAC type I has higher SAC compared to AAC type II and was categorized as class B absorbers at frequency 500Hz. Our results showed that CGW has succeeded in improving the performance of AAC such as work density, compressive strength and SAC. Especially for AAC type I, the samples are suitable for wall application such as partition walls, party walls and sound insulation material.

Boosting rejuvenator diffusivity and asphalt recovery through regulated component ratios based on molecular dynamics method

ABSTRACT The ability of rejuvenators to restore the aged asphalt is critical to the performance of rejuvenated asphalt pavements, depending on the efficient diffusion of aromatic and saturated components in rejuvenators. This study employs molecular dynamics simulations to investigate the diffusion patterns of varying ratios of aromatic and saturated components of rejuvenators in aged asphalt. The mechanical and thermodynamic properties of the rejuvenated asphalt were subsequently evaluated. The results indicate that aromatic components disrupt the π-π interactions between macromolecules in aged asphalt by increasing the distance between macromolecules, inhibiting their aggregation. Additionally, both saturated and aromatic components enhance diffusion efficacy, with the strongest synergistic effect observed at a 1:1 ratio. The introduction of rejuvenators increased the free volume fraction from 24.67% to 28.72%, signifying an enhancement in molecular mobility and permeability within the asphalt, thereby indicating improved diffusion properties of asphalt. The compressive strength (1.8951 GPa) and deformation resistance (2.1754 GPa) increased by 116% and 155% respectively, while shear resistance was restored to virgin asphalt levels (0.7506 GPa). Furthermore, density, cohesive energy density, solubility parameter, and polar molecular aggregation were effectively restored. This research provides valuable insights for designing effective rejuvenators in asphalt pavements.

Study on the Effects of Mg–Si Gangue Compositions within Magnetite on Iron Oxide Crystallization during Pellet Roasting

This article investigates the consolidation performance of high‐magnesium content pellets under varying roast temperatures and Mg–Si elemental contents. The study reveals that as the proportion of high‐Mg–Si ore increases, the strength of preheated pellets decreases from 546 to 470 N at a constant preheating temperature. The rise in magnesium and silicon phases diminishes the oxidation degree of the pellets, requiring a higher sintering temperature to achieve optimal consolidation. The research indicates that at 1200 °C pellets exhibit the highest average compressive strength with the best level of oxidation and secondary crystallization. However, over‐roasting leads to a reduction in pellet strength due to excessive liquid phase interference at 1250 °C. When the high‐Mg–Si raw material proportion is 50 wt%, the pellets with the highest compressive strength of 2843 N are yielded at the sintering temperature of 1200 °C and preheating temperature of 850 °C, which is attributed to the high oxidation, secondary crystallization of magnetite, and the MgO content facilitating the formation of CaO·Fe2O3 liquid phase, resulting in the best pellet consolidation strength.