Mechanical Performance Of Concrete Research Articles

Influence of graphene oxide properties, superplasticiser type, and dispersion technique on mechanical performance of graphene oxide-added concrete

The incorporation of Graphene Oxide (GO) nanomaterial into concrete has gained significant attention due to its potential to enhance mechanical and durability properties. The addition of GO to concrete creates considerable changes in the morphology of the concrete matrix, creating a densified microstructure. Critical parameters significantly affect these microstructural enhancements and, consequently, the final performance in GO-added concrete. These parameters include GO material properties, superplasticiser (PS) type, and dispersion techniques. Therefore, this study investigates the influence of GO on the mechanical performance of concrete, focusing on these critical factors. Unlike existing studies concentrating on a single parameter's effect, this research comprehensively compares how these parameters impact GO-added concrete. Two commercially available GO types (GO-A and GO-B) and two PS types (PS-A and PS-B) are utilised. At the same time, three commonly used mixing techniques, such as mechanical, high-speed, and ultrasonic mixing techniques, are considered for GO dispersion. GO-A is added to concrete in percentages ranging from 0.02% to 0.14% by weight of cement (bwoc), while GO-B ranges from 0.04% to 0.20% bwoc. Based on compressive strength test results, the optimum GO dosages are 0.08% for GO-A and 0.12% for GO-B. The highest strength results are achieved for GO-B added concrete with PS-A addition and following the ultrasonic dispersion method, highlighting these parameters as optimal for maximising GO-added concrete performance. The optimum concrete mix exhibits 33%, 24%, 25%, and 30% increments for compressive strength, indirect tensile strength, flexural strength, and elastic modulus properties at 28 days. This paper provides a deep theoretical explanation of the effects of GO material properties, dispersion techniques, and PS type on GO-added concrete performance. The findings provide valuable insights into selecting suitable parameters for optimising the mechanical properties of GO-added concrete, contributing to the advancement and effectiveness of construction materials.

Effect of mix dosage on rubberized concrete mechanical performance: A multivariable prediction model towards design provisions

The accumulation of end-of-life tires generates significant environmental/economic/social problems worldwide; however, these tires can potentially be used in engineering applications when recycled as crumb rubber (CR). One possibility is to use CR as a replacement for river sand in concrete to reduce the disposal of CR and the use of sand as well as to improve some of concrete’s properties, such as thermal performance and carbon footprint at the expense of some compressive strength reduction. In this study, a novel and simple multivariable model was developed to predict the compressive strength reduction of rubberized concrete (RC) based on a dataset of 287 concrete mixtures from 38 different studies. The approach used in this study quantified the significance of the impact of 10 mix design variables on the evaluation of compressive strength reduction. The final model proposed in this paper considers six explanatory variables (i.e., volume replacement of sand by CR, CR quantity, fine aggregate quantity, coarse aggregate quantity, cement quantity, and water quantity) to predict the compressive strength reduction in which a logarithmic transformation was implemented to achieve a more precise model. The proposed model reached a coefficient of determination of 0.89, significantly better than other existing models with which the proposed model was compared, resulting in a highly accurate and yet easy-to-implement model. Finally, practical design considerations were provided to be used in concrete mix design or the design of minor structural elements.

Performance Study of Sustainable Concrete Containing Recycled Aggregates from Non-Selected Construction and Demolition Waste

In the present study, we investigated the mechanical performance of concrete composed of non-selected construction and demolition waste (C&DW) sourced from both old and new sections of an inactive waste landfill site in Karaj, Iran. Initially, we determined the composition of the coarse and fine C&DW used in concrete production. Subsequently, we meticulously examined the physical and chemical properties of both the C&DW and virgin materials to enable thorough comparisons of the results. We then conducted experimental analyses on 33 concrete mixtures containing recycled C&DW, utilizing various tests, including a compressive strength test (CST) for cylindrical and cubic samples, modulus of elasticity (MOE), wide wheel abrasion test (Capon test), British pendulum number (BPN), and ultrasonic pulse velocity (UPV) test. We considered both non-separated fine and coarse C&DW at different replacement ratios in the recycled concrete (RC). Our findings indicate that using non-separated coarse and fine C&DW in concrete yielded satisfactory results, leading to significant savings in virgin materials required for concrete preparation and promoting sustainable development. Furthermore, non-selected C&DW proved to be a viable sustainable material for similar concrete applications. The results revealed a decrease in brick material consumption in various constructions over the past 20 years in Karaj, contributing to the enhanced strength of C&DW concrete. However, the presence of clay minerals in aged landfill sites can adversely affect concrete performance as a potential destructive factor. Despite the possible negative impact of incorporating fine recycled C&DW materials on concrete mechanical performance, the Capon test results demonstrated that the presence of coarse C&DW can enhance concrete’s wear resistance.

Reinforcing efficiency of nanomaterials on mechanical and interfacial characteristics of green concrete incorporating fly ash cenosphere

As part of coal-burning ashes, fly ash cenosphere (FAC) has not been extensively used on account of its negative impact on the mechanical performance of concrete. Hence, nanomaterials, i.e., nano-silica (NS) and carbon nanotubes (CTNs), were adopted in this study to enhance the performance of green concrete containing FAC. A chemical etching procedure was presented to arouse the internal curing and pozzolanic activity of FAC and was validated by comparing the physical and chemical properties of raw and treated FAC. The reinforcing efficiency of NS and CNTs on concrete containing raw and treated FAC was evaluated by investigating cement hydration, fresh and mechanical properties, microstructure and interfacial performance. Results showed that nanomaterials had higher enhancing efficiency when they were added to the concrete incorporating treated FAC, as an increase of up to 72.22%, 15.32% and 30.18% in 28-d non-evaporable water, 28-d compressive strength and 28-d split-tensile strength, respectively, was achieved. The internal curing and pozzolanic effects made treated FAC have superior interactions with NS and CNTs, thereby contributing to a denser microstructure and better interfacial performance. With the addition of NS and CNTs, a stiffer ITZ was identified between the treated FAC and mortar given a higher Si/Ca ratio, which alleviated the negative impact of FAC on the mechanical properties of concrete.

Investigational studies of asphalt concrete elastic moduli for pavement design

In recent years in the Russian Federation there has been a significant expansion of road materials variety used on highways. However, there is a lack of harmonization of new asphalt concrete of Western European format, with regulatory documents for the non-rigid pavement design, in terms of their design characteristics assignment. In this regard, there is a need to determine and justify the numerical values of the new asphalt concrete mechanical performance used for the non-rigid pavement design when tested for strength. In previous publications authors have presented a new graph-analytical approach to justify the elasticity design moduli of asphalt concrete from GOST R 58406.2-2020. This paper is a continuation of that development and includes the empirical verification results of the analytical method accuracy. Tests were carried out to determine the static laboratory elasticity modulus of asphalt concrete under uniaxial bending loading of bar specimens of some asphalt concrete types from GOST R 58406.2 and best corresponding ones from GOST 9128. To the values obtained, during the experiment, the calculation method developed by the authors earlier was applied. The article presents a study aimed at experimental confirmation of analytically justified calculated values of asphalt concrete elastic moduli according to GOST R 58406.2-2021 for the pavement design.

Water transport and porosity trends of concrete containing integral additions of raw-crushed wind-turbine blade

Raw-Crushed Wind-Turbine Blade (RCWTB) is a novel material from the recycling and non-selective crushing of wind-turbine blades composed of fiberglass-composite fibers and polyurethane and balsa-wood particles. This research evaluates for the first time the water-transport and porosity behaviors of concrete with RCWTB through water-penetration-under-pressure, full-immersion water-absorption, capillarity-water-absorption and mercury-intrusion-porosimetry tests. RCWTB contents of 1.5%, 3.0%, 4.5%, and 6.0% were considered. All the RCWTB concretes yielded adequate results for depth of water penetration under pressure and water-absorption rate, although this waste slightly worsened both properties. RCWTB also increased the proportion of pores between 100 and 250 nm in size, which increased total and capillary effective porosities to maximum values of 13.54% and 13.51%, respectively, and sharply decreased the compression-related mechanical properties of concrete. Capillary effective porosity included the porosity effect of balsa-wood particles on concrete mechanical performance, so it allowed estimating the compression-related mechanical properties with a deviation lower than ±10%.

Effect of Magnetized Water-Based Alkaline Activator on Geopolymer Concrete Mechanical Performance and Durability

One of the most important challenges in developing the concrete industry is to use sustainable materials that are able to improve concrete properties. Magnetized water (MW) is a type of water that can replace tap water (TW) in conventional concrete and enhance its mechanical properties. However, the performance of MW in geopolymer concrete has not been well investigated up to now. The goal of this study is to measure the effect of using an alkaline activator (AA) made of MW on the mechanical properties and durability of fly ash (FA)-based geopolymer concrete. The AA was a mixture of sodium hydroxide (SH) solution and sodium silicate (SS) solution. Eighteen geopolymer concrete mixes were tested for several fresh, hardened, and durability properties. Of these mixes, nine were prepared with AA made of MW and the other nine were the same but prepared with AA made of TW. The preparation of MW was simply carried out by passing TW across permanent magnets of 1.6 Tesla, and then 1.4 Tesla intensities for 150 cycles. The MW-based AA properties were analyzed and compared to those of the conventional TW-based AA. Several mechanical and durability properties were measured. Scanning electronic microscopy (SEM) analysis was also conducted on selected mixes. The outcomes of the hardened concrete tests demonstrated that while using MW to prepare AA solution contained SH with a molarity of 16 M, an SS/SH ratio of 2, an AA/C ratio of 0.4, a W/C ratio of 10%, and a curing temperature of 115 °C could display the best outcomes in this study when used in geopolymer concrete. Using MW in a geopolymer concrete AA could increase its slump by up to 100% compared to that made of TW. Using MW in the AA enhanced the compressive strength by up to 193%, 192%, and 124% after 7, 28, and 56 days, respectively. The SEM analysis showed that using MW clearly enhanced the surface morphology of geopolymer concrete. The proposed geopolymer concrete made using the MW-based AA in this study sheds the light on a new class of eco-friendly concrete that could possibly be used in many structural applications.

Pre-treated corn straw fiber for fiber-reinforced concrete preparation with high resistance to chloride ions corrosion

Chloride ions erosion is a negative factor for concrete sustainable usage. Fiber addition is a potential solution, which promotes a tight concrete structure formation resulting in the resistance of chloride ions. Corn straw is a kind of crop waste widely sourced that can be used as sustainable concrete reinforcement material. The traditional recycling method of corn straw including burnt as straw ash is not environment friendly. This work aims to pre-treat corn straw fiber (CSF) by some convenient methods (untreated, water-treated, alkali-treated) and add treated CSFs directly into concrete to prepare fiber-reinforced concrete with excellent mechanical properties and high resistance ability to chloride ions. The component content of different treated CSFs was tested to study the fibers composition and microstructure changes. The heat of hydration, compressive strength, and flexural strength were tested to study the hydration degree and the effect of different treated CSFs on the concrete mechanical performance. The rapid chloride permeability (RCPT) and chloride migration (RCM) tests were designed to study the reinforced concretes chloride ions resistance ability change. In addition, to further explore the mechanism of mechanical performance and chloride ions resistance ability change, water absorption rate (WAR) and mercury intrusion porosity (MIP) were tested to provide more supporting information from the micro-level. It is concluded that CSF treated by Na2SiO3 has the least impurities and a rougher surface with a larger specific surface area bonding with the cement substrate. Compared to the original concrete, the compressive strength of CSF concrete, WT-CSF concrete, and NT-CSF concrete increased by 15.7 %, 17.8 %, and 33.4 % respectively. The results of RCM and RCPT show a decreasing trend with different treated CSFs addition, the NT-CSF concrete shows the greatest decrease with 20.1 %, and 17.5 %, respectively. Except for the rougher surface and less impurities of CSF, the improvement of mechanical performance and chloride ions resistance ability is mainly due to treated CSF, especially the NT-CSF contributes to a denser structure formation based on the MIP and WAR test results. The viscosity of Na2SiO3 solution acts as a binder that helps to tighten the bonding between substrate and CSF. The water adsorbed by CSF and the alkaline environment provided by Na2SiO3 facilitates hydration decreasing the chloride ions migration. At the same time, the cellulose in CSF containing many hydroxyl and carboxyl groups further contributes to the concrete chloride ion resistance improvement due to its weak conductivity and the binding force of ions exchange.

Evaluation of the sieve analysis effect on the efficiency of PVC waste as sand replacement in concrete mixtures

Recycling materials has become an immerging tendency as a way for preserving natural resources. The waste disposal of polymeric materials has a significant impact on the environment and public health through their practical application in civil engineering constructions. The current experimental study aims to investigate the possibility of using polyvinyl chloride (PVC) waste in concrete and also to evaluate the PVC concrete properties in comparison with ordinary concrete (OC). This investigation research involves reusing the left-over PVC tube wastes and their incorporation in concrete. Three different replacement ratios (5%, 10% and 15%) of natural sand by polyvinyl chloride were considered, taking into account two different sizes (fine and fiber) of polymeric wastes. The effects of each incorporated PVC waste on the compressive strength, and tensile strength were studied. The fresh properties of concrete were investigated by conducting a slump test. The results revealed a decrease in the workability of the fresh PVC concrete compared to ordinary concrete. It was observed that the concrete made with fiber PVC shows a lower workability (decrease of 54%) in comparison with the first one which contains fine PVC aggregates. The concrete made with fiber PVC aggregates improves the compressive strength up to 23.5%. This latter increased simultaneously with increasing the replacement ratio of PVC waste. However, the increase of fine PVC waste content caused a decrease in compressive strength till 21%. The test results also revealed that the concrete mixes with high fiber and moderate fine PVC ratios enhanced the concrete mechanical performance.

Experimental evaluation of alkali-activated and portland cement-based mortars prepared using waste glass powder in replacement of fly ash

The decreasing trend in coal fly ash production has led to a rapidly growing interest in finding alternative materials to replace fly ash in concrete. In this study, the use of glass powder to replace fly ash in concrete was investigated. The performance of portland cement and alkali-activated slag-based mortars containing fly ash (class F) or glass powder (aluminosilicate-based) was evaluated via a series of experiments, including fresh, physical, mechanical, and restrained cracking tests. Notably, a customized restrained shrinkage test was used to investigate the cracking potential. Results showed that the ultra-fine glass powder performed differently in the two binding systems. In the portland cement system, the use of glass powder yielded higher concrete mechanical performance compared to the concrete containing fly ash, while the opposite conclusion was obtained for the alkali-activated system. Comparing the alkali-activated system with the portland cement system, the alkali-activated materials with either fly ash or glass powder had higher free shrinkage and developed cracks much earlier under the restrained drying shrinkage. However, the alkali-activated materials maintained a high level of strain in the steel ring, which was primarily attributed to the development of multiple cracks and their different bonding at the mortar and steel interface.

Combined Effect of Cow Dung Ash and Rice Husk Ash on Mechanical Performance of Concrete

Abstract: Rice Husk Ash (RHA) and Cow Dung Ash (CDA) are agriculturally based pozzolanic materials, these materials are available in huge quantities. This final year project report highlights and presents the results of the study on the use of Cow Dung Ash and Rice Husk Ash as partial replacement of cement in concrete. The experiments were conducted to study the impacts of adding Cow Dung Ash and Rice Husk Ash in several percentages by weight (0%, 5%, 10%, 15%, and 20%) of cement and cure for periods of 28 days before testing for compression strength. The consistency, workability, sieve analysis of aggregates were also tested in this research study. The Compressive test results are 37.75 N/mm2, 31.25 N/mm2, 31.25N/mm2 and 25.25 N/mm2 for 0%, 5%, 10% and 15% replacement of cement with Cow Dung Ash and Rice Husk Ash respectively at 28days. The Workability results gives 45mm, 49mm, 56mm, 68mm and 75mm respectively for 0%,5%, 10%, 15%, and 20% replacement of cement with Cow Dung Ash and Rice Husk Ash. The consistency test results are 0.29, 0.32, 0.36, 0.41 and 0.43 for 0%, 5%, 10%, 15% and 20% replacement of cement with Cow Dung Ash and Rice Husk Ash respectively. The bulk density results are 2452.53 kg/m3, 2370.8 kg/m3, 2380.0 kg/m3 and 2348.5 kg/m3 for 0%, 5%, 10% and 15% replacement of cement with Cow Dung Ash and Rice Husk Ash respectively. The main highlights, it should be highlighted that the more quantity of water is required to standard consistency as the percentages of Cow Dung Ash and Rice Husk Ash are added. Dung Ash and Rice Husk Ash concrete is recommended for use when a ten percentage (10%) of Cow Dung Ash and rice husk ash are not exceeded

Assessment of the PVC Waste Addition Effect on the Concrete Mechanical Performance

Assessment of the PVC Waste Addition Effect on the Concrete Mechanical Performance

Utilization of hybrid fibers in different types of concrete and their activity

Abstract In this work, the influence of using hybrid fibers on the mechanical properties of two types of concrete: high-strength concrete (HSC) and lightweight concrete (LWC) was studied. Using hybrid fibers instead of using only one type reduced the negative effect on concrete mechanical performance. The glass fiber (GF) and polypropylene fiber (PPF) were used in different contents ranged from 0.2 to 1% as weight % of binder content. Moreover, combinations of both fibers “GF + PPF” were used in contents % of “0.3 + 0.5%,” “0.5 + 0.5%,” “0.3 + 1%,” and “0.5 + 1%.” LWC mixes were prepared by replacing 40% of the coarse aggregate of reference mix with volcanic material (pumice) as a volumetric replacing. To produce HSC, the water-to-cement ratio was reduced to 0.3, 10% silica fume was added, and 1% super plasticizer was used to obtain the consistency. Compressive strength, splitting strength, and flexural strength tests were carried out. The results showed that using 0.7% GF displayed the highest increases in compressive, splitting tensile, and flexural strength of HSC and LWC mixes. Furthermore, GF exhibited better performance and higher values in compressive, splitting tensile, and flexural strength tests in comparison with PPF. The optimum hybrid fiber content displaying the highest increment of all tested properties in both concrete types, HSC and LWC, was “0.5% GF + 0.5% PPF.”

A spherical harmonic-random field coupled method for efficient reconstruction of CT-image based 3D aggregates with controllable multiscale morphology

The physical and mechanical performance of concrete is inherently dependent on aggregate morphology including the general shape at coarse-scale, the local roundness at medium-scale and the surface texture at fine-scale. This study develops a computational method for highly efficient generation of realistic 3D aggregates using micro X-ray Computed Tomography (μXCT) images, the spherical harmonic (SH) analysis and a random-field reconstruction algorithm. In this method, the real aggregate surface segmented from CT images is first decomposed and mapped by the SH function to radius fields at different scales, whose statistical data are then extracted to reconstruct new aggregates through a spectral representation method and an innovative folding algorithm. The proposed method is verified by comparison of four morphology indices (sphericity, convexity, roundness and roughness) of the real aggregate and the new ones, and its flexibility in reconstructing new sets of random aggregates with specified morphology indices at selected scales is also demonstrated. As an application, eight sets of Fuller-grade random aggregates with target morphology indices are constructed and packed into a cube container to generate digital concrete specimens. The aggregate sphericity and convexity are found to be linearly correlated with the maximum aggregate volume fraction that can be packed into the cube. The developed method can be also applied to other granular materials, such as pharmaceutical particles, colloids, ceramics, soils and coal.

A Study on Mechanical and Microstructural Characteristics of Concrete Using Recycled Aggregate.

The objective of this paper is to provide a comprehensive study about the performance of concrete using mixed coarse recycled aggregate (MCRA) as an alternative for natural aggregate (NA) at replacement levels of 0, 30, 60, and 100%, which can greatly reduce the environmental pollution by incorporating the construction and demolition wastes in the reproduction of concrete. The focus of this study was to use the raw MCRA that was directly obtained from a recycling plant and not further processed. Initially, MCRA was studied to ascertain if its property meets the recommended Indian standards for natural aggregates. Using the slump test, the workability of freshly prepared concrete with a characteristic strength of 30 MPa was assessed. Additionally, the mechanical performance of concrete was assessed on the specimens prepared in the different forms: cubes, cylinders, and beams. Moreover, Scanning Electron Microscopy (SEM) with EDAX, XRD, and FTIR were used to study the microstructural behavior of selected optimum and control mixes at 7 and 28 days of curing. The studies revealed that a higher MCRA content improved the workability of concrete and 30% replacement of MCRA improved the compressive strength by 11.01, 6.98, 6.19, and 14.24% at 7, 28, 56, and 90 days respectively. At the same time, the 30% replacement of the MCRA mix showed an improved split tensile and flexural strength by 2.92 and 6.26%, respectively. The microstructural analysis showed that the optimum mixture had a more condensed microstructure. Therefore, 30% replacement of MCRA can be incorporated in the characteristic strength of concrete of 30 MPa. In particular, MCRA incorporation had a positive influence similar to conventional concrete on the physical, mechanical, and microstructural properties, which can increase the utilization of all kinds of directly obtained construction and demolition wastes to increase the circular economy in the construction sector.

Effect of Rubber Heat Treatment on Rubberized-Concrete Mechanical Performance

To eliminate the unfavorable effect of the accumulation of end-of-life car tires on the environment, many studies have been conducted to recycle those tires in concrete as a partial or full replacement of its natural aggregates. However, the produced rubberized concrete suffers from low compressive strength due to low adhesion at the rubber/cement interface. Pre-treating of rubber surfaces before use in concrete is the most effective way to overcome this adverse effect on the concrete strength. Several studies introduced different methods to enhance rubberized-concrete strength through pre-treating rubber particles, especially when using a high content of rubber in concrete. This study presents the results of experimental work on the effect of heat treatment on crumb-rubber–concrete mechanical performance. Rubber contents of 40%, 60% and 80% of sand volume were the variables in this study. Workability, density, compressive strength, and impact resistance were the measurements in this experimental work. The results showed that using saturated-surface dry (SSD) rubber can eliminate the adverse effect on concrete slump when using a high rubber volume or the heat-treated rubber. Using heat-treated rubber at 200 °C for 2 h as 40%, 60%, and 80% displayed compressive strength recoveries of 14.9%, 10.4% and 9.7%, respectively. Heat treatment of 40%, 60%, and 80% rubber contents increased the impact resistance for ultimate failure by 57%, 28%, and 7%, respectively, compared with those of the control mix. The thermal treatment enhanced the impact resistance at ultimate failure by 37%, 28%, and 15%, respectively, for mixes containing 40%, 60%, and 80% rubber contents compared with those of as-received rubber.

Inverse analysis-based model for the tensile behaviour of fibre-reinforced concrete with manufactured and waste tyres recovered fibres

The urgency of finding green solutions within the construction industry encouraged, in latest years, the adoption of sustainable materials for structural concrete. One of the most up-and-coming proposal is the use of recycled steel fibres, to complement or possibly replace traditional steel reinforcement. Nevertheless, the contribution of the fibres on the mechanical performance of concrete is still uncertain and requires further investigation. This study is aimed at providing an analytical model for the tensile response of concrete reinforced with manufactured steel fibres and recycled steel fibres recovered from waste tyres. The proposed model features several parameters ruling the cracking strength, the post cracking behaviour and the residual tensile strength of fibre-reinforced concrete. The parameters in the analytical model were calibrated by numerical simulation of toughness tests on specimens with different types and contents of fibres in the mixture. A satisfactory simulation of experimental load-crack tip opening displacement curves was obtained, with numerical-vs-experimental curve scatter lower than 10%. However, the variability of experimental results hindered obtaining an accurate blind simulation of additional tests selected from the literature. On the other hand, a clear correlation between the parameters ruling the cracking strength-to-residual strength ratio and fibres amount was identified for both recycled and manufactured fibres. The outcome of this study showed that the proposed model can be used in simplified design approaches, to account for the fibres’ type and content in the evaluation of tensile response of fibre reinforced concrete.

Influence of Limestone Fillers on Rheological and Mechanical Performance of Concrete

This article reports the study of the impact of the addition of 0/80 mm limestone fillers on the workability and strength of ordinary concretes. Its aim is to develop sands containing a high rate of fillers available in large quantities in Algeria and to identify the possible proportions that can be introduced without compromising the quality of the concrete. The study consists of gradually inserting a rate of fillers of 0, 6, 12, 18 and 24% in the cement mixes. The variation was studied by maintaining a constant maneuverability. Physical and mechanical, microstructural properties of durability were studied. The results obtained showed that the concretes are very influenced by the addition of fillers and highlight the existence of an optimum rate of performance. The addition of a high percentage of fines (up to 18%) does not seem to affect the mechanical and hydraulic characteristics of the concretes.

Mechanical Characterization of Industrial Waste Materials as Mineral Fillers in Asphalt Mixes: Integrated Experimental and Machine Learning Analysis

In this study, the effect of seven industrial waste materials as mineral fillers in asphalt mixtures was investigated. Silica fume (SF), limestone dust (LSD), stone dust (SD), rice husk ash (RHA), fly ash (FA), brick dust (BD), and marble dust (MD) were used to prepare the asphalt mixtures. The obtained experimental results were compared with ordinary Portland cement (OPC), which is used as a conventional mineral filler. The physical, chemical, and morphological assessment of the fillers was performed to evaluate the suitability of industrial waste to replace the OPC. The volumetric, strength, and durability of the modified asphalt mixes were examined to evaluate their performance. The experimental data have been processed through artificial neural networks (ANNs), using k-fold cross-validation as a resampling method and two different activation functions to develop predictive models of the main mechanical and volumetric parameters. In the current research, the two most relevant parameters investigated are the filler type and the filler content, given that they both greatly affect the asphalt concrete mechanical performance. The asphalt mixes have been optimized by means of the Marshall stability analysis, and after that, for each different filler, the optimum asphalt mixtures were investigated by carrying out Indirect tensile strength, moisture susceptibility, and abrasion loss tests. The moisture sensitivity of the modified asphalt mixtures is within the acceptable limit according to the Indian standard. Asphalt mixes modified with the finest mineral fillers exhibited superior stiffness and cracking resistance. Experimental results show higher moisture resistance in calcium-dominant mineral filler-modified asphalt mixtures. Except for mixes prepared with RHA and MD (4% filler content), all the asphalt mixtures considered in this study show MS values higher than 10 kN, as prescribed by Indian regulations. All the values of the void ratio for each asphalt mix have been observed to range between 3–5%, and MQ results were observed between 2 kN/mm–6 kN/mm, which falls within the acceptable range of the Indian specification. Partly due to implementing a data-augmentation strategy based on interpolation, the ANN modeling was very successful, showing a coefficient of correlation averaged over all output variables equal to 0.9967.

Partial Substitution of Binding Material by Bentonite Clay (BC) in Concrete: A Review

Concrete consumes millions of tons of cement, which causes global warming as cement factories emit huge amounts of carbon dioxide into the atmosphere. Thus, it is essential to explore alternative materials as a substitute of OPC, which are eco-friendly and at the same time cost-effective. Although there are different options available to use industrial waste instead of cement, such as waste glass, waste marble, silica fume fly ash, or agriculture waste such as rice husk ash, wheat straw ash, etc., but bentonite clay is also one of the best options to be used as a binding material. There are a lot of diverse opinions regarding the use of bentonite clay as a cement substitute, but this knowledge is scattered, and no one can easily judge the suitability of bentonite clay as a binding material. Accordingly, a compressive review is essential to explore the suitability of bentonite clay as a cementitious material. This review focuses on the appropriateness of bentonite clay as a binding material in concrete production. The attention of this review is to discuss the physical and chemical composition of BC and the impact of BC on the fresh and mechanical performance of concrete. Furthermore, durability performance such as water absorption, acid resistance and dry shrinkage are also discussed. The results indicate that bentonite clay increased the mechanical and durability performance of concrete up to some extent but decrease its flowability. The optimum proportion of bentonite clay varies from 15 to 20% depending on the source of bentonite clay. The overall study demonstrates that bentonite clay has the creditability to be utilized partially instead of cement in concrete.