Replacement Of Aggregate In Concrete Research Articles

Utilization of steel slag as partial replacement for coarse aggregate in concrete

The utilization of steel slag for industrial and construction purposes has gained significant attention in recent years due to its abundant availability and potential environmental benefits. This study explores the feasibility of utilizing steel slag as a coarse aggregate in concrete, aiming to determine the optimal replacement percentages for desired mechanical and structural properties. Experimental investigations were conducted, substituting steel slag for conventional coarse aggregate in varying proportions. The concrete mixtures were tested for compressive strength, flexural strength, workability, and other parameters. The results demonstrate the promising potential of incorporating steel slag as a partial replacement for coarse aggregate. The mixture with 30% steel slag replacement exhibited favorable strength properties and workability. Both compressive and flexural strengths showed significant improvement, highlighting the viability of steel slag as an alternative to conventional coarse aggregate. The findings provide valuable guidance for engineers, researchers, and decision-makers in the construction industry regarding the practical benefits and considerations of using steel slag in concrete mixtures. This utilization promotes resource efficiency, reduces environmental impact, and maintains or enhances the mechanical and workability properties of concrete.

Feasibility Study on the Use of Iron Ore Tailings as Fine Aggregate with Glass Fibre in Concrete

Concrete is the most widely used building material in the world, but its production has significant environmental consequences, including high carbon emissions and natural resource depletion. As a result, there is an increasing interest in the development of sustainable concrete technologies that reduce concrete’s environmental footprint while maintaining its performance and durability. Partially replacing fine aggregate with industrial waste is one such approach. It is a great practice for developing sustainable concrete that can help with environmental problems caused by the dumping of these waste materials at the same time maintaining the performance of concrete. It also provides economic and social benefits in addition to the environmental benefits. iron ore tailings is one such industrial waste that is the by-product of iron ore beneficiation process which has shown the potential for partial replacement of fine aggregate in concrete. In addition, glass fibre is added to improve the tensile property of concrete. A concrete mix of M20 grade were prepared by replacing fine aggregate with iron ore tailing at replacement level 15%, 25%, and 35% and the optimum replacement percentage was obtained. Further, glass fibre was added at the dosage of 0.5% by the weight of cement to the mix with optimised replacement of iron ore tailings and tests were conducted. This work also examines concrete’s physical, mechanical and durability properties with partial replacement of fine aggregate with iron ore tailings and glass fibre by conducting tests on strength and durability. Results obtained indicates incorporation of iron ore tailing with concrete reduces the workability of concrete, and the addition of glass fibre improved the compressive strength and split tensile strength. Durability tests show an increase in water absorption with the addition of iron ore tailings and a medium level of chloride penetration. The study showed the use of iron ore tailing as a sustainable alternative to fine aggregate in concrete.

Upcycling of End-of-Life-Vehicle (ELV) plastics as a replacement for natural fine aggregate in concrete

End-of-life vehicle (ELV) plastics pose technical challenges in conventional recycling due to their diverse polymer compositions. Consequently, landfilling remains the prevailing disposal method. This study explores an innovative approach by upcycling ELV plastics as a substitute for natural sand in concrete. The study investigates the physical, mechanical and economic performance of ELV plastic-containing concrete. Plastic aggregates were prepared from real-world ELV plastics, featuring particle sizes below 4.75 mm, with over 90 % falling within the range of 1.18–4.75 mm. The research involves replacing natural sand with ELV plastics at varying volumes (0 %, 15 %, 25 %, 35 %, and 40 %) and examines the effect of sand replacement on various concrete properties. The results suggest that as the replacement ratio increases, the workability, density, and strength of concrete decrease. However, the 28-day compressive strength of concrete at the maximum replacement rate of 40 % was found to be 39 MPa, which suffices for certain non-structural strength applications, such as traffic routes, shared-use paths, local streets and curbs. In addition, compared to previous studies using mixed commodity plastics, ELV plastics lead to significantly lower strength reductions at high replacement ratios. Scanning Electron Microscopy (SEM) analysis reveals a distinctive rough and fibrous aggregate morphology, which enhances physical binding and provides bridging effects within the concrete matrix, potentially mitigating strength loss. Moreover, the economic analysis highlights a significant potential to commercialize ELV plastics for concrete applications. This study demonstrates that ELV plastics can be effectively used at high replacement rates (up to 40 % by volume) in non-structural applications.

Study On Partial Replacement of Powdered Waste Plastic with Fine Aggregates in Concrete

Using powdered waste plastic as a partial replacement for fine aggregates in concrete is a concept that has gained attention in recent years as a sustainable and environmentally friendly approach to waste management. Incorporating waste plastic into concrete can have several potential benefits, but it also comes with certain challenges. The objective is to develop a suitable composition for a concrete mixture by replacing fine particles with pulverised and granular plastic. To attain the desired strength, the design incorporates a combination of pulverised and granular plastic in concrete, taking into account specific properties such as density, workability, flexural strength, compressive strength, and tensile strength. The restricted movement of aggregates caused by the plastic's resistance could explain the impact of the plastic on the concrete's workability. Moreover, the dried density is reduced, resulting in the formation of a lightweight concrete. The inclusion of waste plastic material in concrete results in a reduction of compressive strength compared to traditional concrete.

Utilization of Plastic Waste as a Partially Replacement of Course Aggregate in Concrete

Utilization of Plastic Waste as a Partially Replacement of Course Aggregate in Concrete

Suitability of Crushed Sandcrete Block (CSB) as a Partial Replacement for Fine Aggregate in Concrete Structures

In concrete structures, debris generated from construction, renovation, and demolition of buildings is often referred to as construction and demolition waste. These waste materials may be very important to recycle for several reasons for instance, recycling materials such as glass, metal, concrete, and wood waste can lessen our reliance on virgin resources, preserve natural resources, and lessen the negative environmental effects of resource exploitation. The suitability of crushed sandcrete block (CSB) for use as a partial replacement for fine aggregate in concrete was examined. The physical and mechanical properties of the crushed sandcrete block and river sand were determined and compared. The specific gravity of the crushed sandcrete block was found to be 2.58 while that for river sand was 2.66. The concrete with compressive strength of 25N/mm2 at 28 days’ hydration period was calculated for the normal mixture as the control. The percentage mix of the fine aggregate was substituted with CSB in different mix proportions of 0:1(0%), 1:3(25%), 1:2(33.3%), 1:1(50%), 2:1(66.7%), 3:1(75%) and 1:0(100%) of crushed sandcrete block and river sand by weight as fine aggregate. The concrete cubes were cured, and compressive strength tests were carried out at 7, 14, and 28 days. It was observed that the 28-day density and compressive strength for concrete cubes with crushed sandcrete block alone as fine aggregate (i.e. 100%) were found to be 2420kg/m³ and 22N/mm² respectively compared to the 0:1(0%) proportion which was found to be 2485kg/m³ and 26N/mm² respectively. It was observed that the density and compressive strength reduced with the increasing addition of CSB in all the proportions.

Developing a sustainable self-compacting geopolymer concrete with 100% geopolymer-coated recycled concrete aggregate replacement

PurposeConcrete, the second most used material in the world, surpassed only by water, relies on a vast amount of cement. The process of cement production emits substantial amounts of carbon dioxide (CO2). Consequently, it is crucial to search for cement alternatives. Geopolymer concrete (GC) uses industrial by-product material instead of traditional cement, which not only reduces CO2 emissions but also enhances concrete durability. On the other hand, the disposal of concrete waste in the landfills represents a significant environmental challenge, emphasising the urgent need for sustainable solutions. This study aimed to investigate waste concrete's best form and rate as the alternative aggregates in self-compacting and ambient-cured GC to preserve natural resources, reduce construction and demolition waste and decrease pertinent CO2 emissions. The binding material employed in this research encompasses fly ash, slag, micro fly ash and anhydrous sodium metasilicate as an alkali activator. It also introduces the best treatment method to improve the recycled concrete aggregate (RCA) quality.Design/methodology/approachA total of25%, 50% and 100% of coarse aggregates are replaced with RCAs to cast self-compacting geopolymer concrete (SCGC) and assess the impact of RCA on the fresh, hardened and water absorption properties of the ambient-cured GC. Geopolymer slurry was used for coating RCAs and the authors examined the effect of one-day and seven-day cured coated RCA. The mechanical properties (compressive strength, splitting tensile strength and modulus of elasticity), rheological properties (slump flow, T500 and J-ring) and total water absorption of RCA-based SCGC were studied. The microstructural and chemical compositions of the concrete mixes were studied by the methods of energy dispersive X-Ray and scanning electron microscopy.FindingsIt is evident from the test observations that 100% replacement of natural aggregate with coated RCA using geopolymer slurry containing fly ash, slag, micro fly ash and anhydrous sodium metasilicate cured for one day before mixing enhances the concrete's quality and complies with the flowability requirements. Assessment is based on the fresh and hardened properties of the SCGC with various RCA contents and coating periods. The fresh properties of the mix with a seven-day curing time for coated RCA did not meet the requirements for self-compacting concrete, while this mix demonstrated better compressive strength (31.61 MPa) and modulus of elasticity (15.39 GPa) compared to 29.36 MPa and 9.8 GPa, respectively, for the mix with one-day cured coated RCA. However, incorporating one-day-cured coated RCA in SCGC demonstrated better splitting tensile strength (2.32 MPa) and water absorption (15.16%).Research limitations/implicationsA potential limitation of this study on SCGC with coated RCAs is the focus on the short-term behaviour of this concrete. This limited time frame may not meet the long-term requirements for ensuring the sustained durability of the structures throughout their service life.Originality/valueThis paper highlights the treatment technique of coating RCA with geopolymer slurry for casting SCGC.

The Effect of Steam Curing on the Early Compressive Strength of Glass Powder Concrete

<p class="Abstract">Glass bottle waste is non-biodegradable and concerns about its impact on the environment. One alternative is to use recycled glass bottle waste in a form of glass powder as a partial replacement for fine aggregate in concrete. This study compared the glass powder concrete containing 20% glass powder as a partial replacement for fine aggregate treated by steam curing to the normal concrete treated by immersion curing. To obtain a higher early strength, the glass powder concrete will be treated with steam curing method for total duration of 9 hours. The test results showed that glass powder concrete treated with steam curing experienced a significant increase of 40.7% in compressive strength at 1 day of age with a compressive strength of 7.84 MPa compared to normal concrete of 5.56 MPa, an increase of 57.0% at 3 days of age with a compressive strength of 16.88 MPa compared to normal concrete of 10.75 MPa, and an increase of 14.0% at 7 days of age with a compressive strength of 23.86 MPa compared to normal concrete of 20.94 MPa. The results of this study indicated that steam curing has the effect of increasing the early compressive strength of concrete at the age of 1, 3 and 7 days. In addition, the use of 20% glass powder as a partial replacement for fine aggregate can contribute to the utilization of non-biodegradable glass bottle waste.</p>

A Study of Physical and Mechanical Properties using Kenaf Core as Coarse Aggregate Replacement in Concrete

Kenaf is well known for its one of the highest rankings of biomass producers compared to other fibre crops which excessive amounts of biomass could lead to contamination of soil due to its pollutants elements. Not only that, the high demand for aggregate for concrete production requires massive use of natural stone materials which leads to the destruction of the ecological balance of the environment. As in Malaysia, kenaf core is commonly used and available in abundance after the processing of kenaf stems for bast fiber production. Thus, this research aims to determine the physical and mechanical properties of kenaf core as fine aggregate replacement in concrete. There were 45 samples of the concrete cube of 100 mm x 100 mm with the percentage used of 0, 5, 15 and 25 % kenaf core replacement. A density test was conducted as well as a compressive strength test to obtain the objectives of the study. Findings reveal that the control sample still has the highest value of compressive strength of 34.7 MPa while 5 % of kenaf core concrete shows 28.50 MPa which slight decrease in the value in comparison. The value then gradually decreases as the percentage of the kenaf core increases. The density test also reveals that 25 % kenaf core shows the lowest value of density by 1419.78 kg/m3 compared to normal concrete. Thus, this indicates that the optimum percentage of kenaf core used was 5 % even though it still did not surpass 0 % concrete.

Behaviour of carbon or glass FRP-confined rubberised concrete under monotonic compression

This paper presents a comparative assessment of the compressive behaviour of rubberised concrete (RuC) confined with FRP jackets. In total, three RuC mixes were investigated with rubber content of 6%, 12% and 18% of the total aggregate volume, as well as a conventional concrete mix as a reference. A total of 100 cylindrical concrete specimens (Ø100 × 200 mm) subjected to monotonic axial compression were tested. Confinement scheme comprised 1 or 2 FRP layers of either carbon or glass uniaxial fabric. The mechanical properties, stress–strain behaviour, and confinement effectiveness ratios were assessed. The discussion includes a comparative assessment of the influence of rubber content, confinement and the type of fibre of the fabrics used on the aforementioned properties. The efficiency of analytical models in predicting the experimental results was also investigated. The results revealed a significant reduction of the compressive strength when crumb rubber was used as mineral aggregate replacement in concrete. FRP confinement of RuC was able to mitigate the reduction in compressive strength. Confinement of RuC with glass or carbon FRP jackets having similar axial rigidity resulted in similar stress–strain behaviour, which was mostly affected by the rubber content. Existing analytical models were able to predict the experimental results with moderate accuracy.

Application of Coffee Husk Ash as Partial Replacement of Fine Aggregate in Concrete

The task of turning agricultural waste into practical construction and building materials has been placed before civil engineers. Coffee husk is produced in vast amounts due to the global commerce of coffee beans, which are incinerated into ash when used as fuel, producing coffee husk ash (CHA). Even though many researchers have worked on the utilization of CHA in concrete, they have been used as partial cement replacement but not as a replacement of aggregates. The experimental study of the performance of concrete on fine aggregate replaced partially with CHA is represented in this paper. The fine aggregate is replaced by 0%, 2%, 4%, 6%, and 8% by weight of CHA. The performance of the partially replaced fine aggregate with CHA is reviewed by considering the compressive strength and workability of fresh concrete and the splitting tensile strength, flexural strength, durability under acid and alkaline media, thermal conductivity, and rapid chloride permeability test of hardened concrete. The results indicate that the partial replacement of fine aggregate with 4% of CHA (CHA04) in concrete provides a positive impact to all the selected performance parameters. The compressive strength, flexural strength, and splitting tensile of the CHA04 mix were 43.4 MPa, 3.7 MPa, and 2.44 MPa, respectively, which were 28.4%, 19.35%, and 1.66%, respectively, greater than normal concrete mix (CHA00). Even the study of acid and alkaline attack on the CHA04 mix showed lesser strength reduction as compared to other mixes. The RCPT showed less chloride permeability, and the thermal conductivity is higher for CHA04, indicating lesser voids compared to other mixes. With the help of this investigation, it can be said that fine aggregate replacement with 4% CHA has the best strength and durability properties compared to regular concrete.

Utilizing Crushed Waste Glass as a Sustainable Replacement for Fine Aggregate in Concrete

Concrete, a vital material in modern construction, combines strength, durability, and fire resistance. However, the conventional use of river sand in concrete is ecologically concerning due to its scarcity and environmental impact. To address this, waste glass is explored as a sustainable replacement for fine aggregate. This study investigates the effects of crushed waste glass on concrete workability, water absorption, compressive strength, and flexural strength. Different glass replacement levels (0%, 10%, 20%, and 30%) and curing periods were considered. The research aims to optimize glass content, evaluate its impact on concrete properties, and compare its environmental effects with traditional methods. The results indicate that waste glass improves workability and reduces water absorption. Compressive and flexural strengths initially increase with glass content but decrease at higher levels, due to potential alkali-silica reaction. The study concludes that waste glass can be effectively utilized in concrete to enhance sustainability and resource conservation. Further research is recommended to explore specific applications and long-term effects.

Optimal design of sustainable recycled rubber-filled concrete using life cycle assessment and multi-objective optimization

This research studies the use of recycled crumb rubber (CR) as partial replacement for fine aggregates in concrete. Fracture analysis and Life Cycle Assessment (LCA) approach are used to assess 10 different Recycled Rubber-Filled Concrete (RRFC) mixtures by evaluating damage across 22 impact categories using the ReCiPe 2016 methodology. Multi-objective optimization (MOO) is deployed to identify optimal mixture proportions of RRFC using a BPNN-AGE-MOEA model. The MOO process considers concrete characteristic objectives, environmental assessment, and cost, while imposing boundary values for target compressive strength, water-to-cement (W/C) ratio, and CR content. The results show that increasing the CR content increases toughness and energy absorption capacity yet decreases the compressive and tensile strengths. Reducing the W/C ratio and increasing the CR content improved fracture characteristics and crack resistance. It is also found that the mechanical properties and the transportation stage of RRFC manufacturing have a significant effect on the environmental footprint. Careful material selection and transportation strategies can significantly reduce this environmental footprint. The proposed MOO approach using the predictive BPNN model successfully resolved the complex relationship between economic and environmental considerations of mixture design variables. To achieve a balance of environmental impact, affordability, and performance, the study underlines the need for carefully balancing the W/C ratio and CR content. The findings suggest that enhancing fracture properties while limiting the environmental impact is possible, allowing to promote wider application of recycled rubber in concrete.

Utilizing Polyethylene Terephthalate PET in Concrete: A Review.

In general, plastic waste has been growing remarkably. Numerous waste plastic products are generated by manufacturing processes, service industries, and municipal solid waste (MSW). The increase in plastic waste increases concern about the environment and how to dispose of the generated waste. Thus, recycling plastic waste becomes an alternative technique to the disposal of plastic waste in a limited landfill. One of the solutions is to use plastic waste as recycled material in concrete construction to produce what is called green concrete. This research illustrates a summary of studies that utilized polyethylene terephthalate (PET) in concrete as a volume ratio or concrete aggregate replacement. It presents data with regard to mixing design and concrete behavior when PET is used. Moreover, using PET in concrete industries may reduce environmental pollution such as the emission of carbon dioxide and plastic waste disposal problems.

Machine learning optimization and prediction of waste glass used as partial replacement of coarse aggregate in concrete

Machine learning optimization and prediction of waste glass used as partial replacement of coarse aggregate in concrete

Economic viability analysis of recycling waste plastic as aggregates in green sustainable concrete

Plastic waste management is one of the major global challenges at present. Recycling single used plastic waste as partial replacement of natural aggregates in concrete may reduce problems regarding mismanagement of plastic waste and unsustainable utilisation of natural resources as aggregates. This concept has been explored in many studies and positive results are obtained, but it has not been materialized at a large scale due to the uncertainty regarding economic viability. The present study therefore focuses on the economic aspects of using Polyethylene based fine aggregates and Polyethylene Terephthalate based coarse aggregates as partial replacement (10%, 20%, 30% and 40%) of natural fine and coarse aggregates separately and simultaneously, with special emphasis given on environmental and social cost. A material flow diagram using STAN is first developed to calculate plastic waste generation. An industrial survey has been conducted to estimate production cost of plastic aggregates, while social cost as WTP is determined through CVM method. The result shows that the total cost of concrete decreases with increase of replacement percentage and cost reduction varies between 0.65% and 7.58% compare to conventional concrete depending on the percentage and type of replacement without compromising strength. So, alongside being hugely beneficial to environment and society in terms of reduction of leachate and greenhouse gas generation, micro-plastic pollution, requirement of landfill area, mosquito borne diseases, erosion, sedimentation, land loss etc.; the concept of recycling plastic waste as partial replacement of natural aggregates in concrete has been proved to be economically viable and beneficial too.

Feasibility study on utilisation of discarded waste material as a partial replacement for coarse aggregate in concrete

Electronic waste, or Discarded waste. The electronic goods that have become unwanted, non-functional, or out-of-date, and have meritoriously grasped the end of their worthwhile lives are known as Discarded waste. Aluminium, bronze, gold, silver, resins, and ferrous metals are just a few of the valuable, reusable materials that can be found in waste that has been discarded. All across the world, discarded waste disposal is a routine occurrence. The usage of Discarded waste materials is only a piece of the puzzle when it comes to environmental and ecological challenges. Concrete is the most significant engineering material, and changing the concrete philosophy may be more achievable by adding or replacing some of the ingredients. The research of concrete employing E trash as a limited replacement for coarse clusters is presented in this work. For various substitutions of coarse aggregate with Discarded waste on M30 grade concrete, the compressive strength, split tensile strength, and flexural strength of concrete were investigated. The concrete gains higher compressive strength after 15 percent partial replacement of coarse aggregate with E trash at 7 and 28 days. The greatest optimum content of the discarded waste-replaced concrete occurs at 15% partial replacement of coarse aggregate accordingly as part of this project.

A Laboratory Study of Use of Crumb Rubber as Partial Replacement of Fine Aggregate in Concrete

Abstract: The aim of this study is to analyse the effect of addition of crumb rubber on the various properties of concrete. The crumb rubber is used as replacement over aggregates in the concrete mix. Crumb rubber is prepared from the scraps of tyres. In this study aggregates are replaced by 0%, 30%, 40%, 60%, 100% crumb rubber. The rubberized concrete is tested for slump and compression strength. It is found that the slump of rubberized concrete increases first but as the amount of rubber is increased the slump starts decreasing. It is observed that initial compression strength of rubberized concrete reduced significantly but the final strength is found to be more than that of ordinary concrete. Waste tyres cause tremendous pressure and ecological issues for the entire tyre industry when accumulated in cultivated land or combusted. Crumb rubber (<5 mm) grinded from waste tyres was introduced to substitute for natural fine aggregate in concrete and effectively solves the consumption challenge. This paper reviews the performance of concrete with crumb rubber as fine aggregate, providing evidence for crumb rubber concrete (CRC) materials design and application. Crumb rubber is characterized with light specific gravity, hydrophobicity and air entrapment in comparison with natural fine aggregate, inducing significant reduction in workability of fresh CRC and exhibiting poor bonding performance with cementitious matrix. By summarizing the compressive/tensile strength, elastic modulus and fracture behaviour of CRC at various rubber content, prediction models of strength reduction factors are proposed. The main reasons for strength deterioration are weak interface transition zone (ITZ) performance and non-uniform distribution of rubber particles. Water/chloride permeability, electrical/carbonation resistance and drying shrinkage of CRC are discussed for durability performance of CRC. Physical/chemical pre-treatments of rubber could alleviate the hydrophobicity and improve the mechanical and durability performance of transition zones between rubber and cement paste. Accordingly, scopes concerning the recycling of crumb rubber and its performance optimization are expected in future studies.

Improvement of Computational Efficiency and Accuracy by Firefly Algorithm and Random Forest for Compressive Strength Modeling of Recycled Concrete

It is an important direction for the sustainable development of pavement to mix the discarded concrete blocks with gradation according to a certain proportion after crushing, cleaning and other technological processes, partially or completely replace aggregate, and then add cement, water, and so on to make recycled concrete for pavement paving, but the traditional evaluation model for the compressive strength (CS) of recycled concrete cannot meet the requirements of efficient calculation. To address such issues, the present research proposed to apply the firefly algorithm (FA) to optimize the random forest (RF) model. The results were demonstrated by comparing the consistency of predicted and actual values, and also by analyzing the correlation coefficient (R) and root-mean-square error (RMSE). Higher R values (0.9756 and 0.9328) and lower RMSE values (3.0752 and 6.4369) for the training and test sets present the reliability of the FA and RF hybrid machine learning model. To understand the influence law of input indexes on the output index, the importance and sensitivity of variables are further analyzed. The results displayed that effective water-cement ratio (WC) and nominal maximum recycled concrete aggregate size (NMR) have the greatest impact on the output variable, with importance scores of 2.5947 and 2.4315, respectively, while the change in the recycled concrete aggregate replacement rate (RCA) has a weak influence, with an importance score of 0.4695. Introducing FA to RF for the compressive strength modeling of recycled concrete can significantly improve the computational efficiency and accuracy.

Insight into the perspectives of waste foundry sand as a partial or full replacement of fine aggregate in concrete

Insight into the perspectives of waste foundry sand as a partial or full replacement of fine aggregate in concrete