Conventional Coarse Aggregate Research Articles

Investigation of durability properties for structural lightweight concrete with discarded vehicle tire rubbers: A study for the complete replacement of conventional coarse aggregates

This innovative study presents the manufacture of structural lightweight concrete (SLWC) with 100 % waste coarser tire rubber and sets an inaugurating move in identifying its durability properties. Two newly designed casting moulds were developed to enhance the strength and durability properties of rubberized concrete without any conventional coarse aggregates. Slump values of different fresh RuC mixes varied from 84 to 122 mm, maintaining the requirement denoted by ACI 213R. Density and compressive strength of novel SLWC were determined. The durability properties, including water absorption, sorptivity, shrinkage, sulfate attack and rapid chloride penetration, were evaluated at 28-, 56-, 90-, and 180-day.

Assessment of the Flexural Strength of No-Fines Recycled Aggregate Concrete Prisms

This study investigated experimentally the flexural strength of no-fines recycled aggregate concrete, produced using 20-70% replacement of conventional coarse aggregates with coarse aggregates from demolished waste. Six prisms in each dosage with a 1:4 mix and 0.5 water-binder ratios were prepared. A batch of prisms with conventional aggregates was also cast to compare them with the proposed concrete. An equal number of samples were cured for 7 and 28 days and tested under a gradually increasing central point load to examine failure load, central deflection, and flexural strength. The comparison of results showed an increasing trend in deflection with an increase in the dosage of recycled aggregates. The 7-day cured samples had approximately 2.6 times the deflection of conventional concrete. However, the deflection at all replacement levels remained less than that allowed by ACI-318. The results showed a decreasing trend in flexural strength with an increase in the dosage of recycled aggregates. The 40% replacement sample had a less than 20% strength reduction and is recommended as the optimum level of replacement of conventional aggregates for the production of no-fines recycled aggregate concrete.

An experimental investigation on the strength of concrete by partial replacement of aggregate using E-waste

E-waste is one of the fastest growing sector with the growth of 3–4% yearly, its was estimated to raise upto 55 million tons by 2025. Nowadays, inappropriate disposal of e-waste creates many environmental pollution in both developed and developing countries. Many researches have started to use the waste materials in the production of concrete including e-waste components. Now the recycling of e-waste creates the tremendous issues can cause several health hazards. The main objective of the study is to estimate the usage of printed circuit board to replace the conventional coarse aggregate at 12% for M25 grade concrete. In this paper, PCB of e-waste is used for the purpose of replacement of coarse aggregate. The maximal compressive strength was gained at 12% by partial replacement of e-waste plastic. The tensile and flexural strength also gains the maximal strength at 12%. It’s observed that the PCB of the E-waste concrete by using of with and without plasticizer reached its maximum strength at 12% replacement of coarse aggregate.

Feasibility study on utilization of coconut shell aggregates in concrete

Several materials are being used in concrete as a replacement to coarse aggregates. The present study focuses on experimenting with using Coconut Shell Aggregates (CSA) as replacement to coarse aggregates partially. The high strength and modulus of the coconut shell make it a suitable coarse aggregate for concrete applications. The replacement levels were set at 10%, 15%, and 20%. The experimental results revealed that CSA, when replaced with conventional coarse aggregates, gave satisfactory compressive strength up to 15% replacement, beyond which the strength dropped below the required value. In addition, the use of CSA in concrete significantly reduces the self-weight of concrete, thus contributing to the economy of construction.

Mechanical characterization of the concrete mixture, including steel slag aggregate and steel fibres

Steel slag is a major by-product of the steel industry, its waste management poses serious environmental threats. The slag produced by the steel industries and used as an aggregate in concrete is a sustainable key for the optimal and efficient use of natural mineral resources. In the past, numerous studies have been conducted and engineering solutions have been proposed to find the desired proportion of steel slag in concrete. The present work primarily focuses on the mechanical characterization of concrete mixes adopting Steel Slag Aggregates (SSA) as a substitution for conventional Coarse Aggregates (CA). Furthermore, an optimal concrete composition has been proposed to maximise the load-bearing strength of the concrete. First, following the standard benchmarking procedure, concrete mechanical properties are obtained. Next, the effect of replacing CA (10%, 20%, 30%, and 40%) by weight with SSA in the concrete mix is studied. The required number of cubes was cast for optimisation, and mechanical characterization (compressive, split tensile, and shear tests) was performed on the M45-grade concrete with SSA. Finally, the study has been extended with the inclusion of steel fibres in the previous optimal SSA-concrete mix. The optimum steel fibre volume fraction has been determined by performing various mechanical tests on the steel fibre concrete mix. The experimental results show that SSA can significantly improve the mechanical performance of concrete. The ideal percentage to replace CA with SSA in the concrete mixture (CM2) is 30%, which improves the concrete's compressive strength, split tensile strength, and shear strength in comparison to regular concrete. Additionally, adding steel fibres to the ideal mix (CM2) has very less impact on compressive strength but increases tensile strength and shear strength.

Effects of Polypropylene Waste Addition as Coarse Aggregates in Concrete: Experimental Characterization and Statistical Analysis

In recent times, thermoplastic waste materials are being extensively used as fine and coarse aggregates in the concrete mix as an environmentally friendly construction material. This study aims at utilizing polypropylene (PP) as a partial substitute for the conventional coarse aggregates in M30 grade concrete. The different replacement levels of coarse aggregates such as 0%, 20%, 40%, and 60% by weight were used in concrete. Sieve analysis, specific gravity, and water absorption tests were performed in all replacement levels of aggregates. The mechanical (compressive and split tensile tests) tests were conducted after 3, 14, and 28 days. The change in mechanical properties of concrete with the addition of different weight proportions of plastics was studied experimentally. Further, experimental values were predicted using the two-parameter Weibull distribution and artificial neural network (ANN)-based statistical approaches. The Levenberg–Marquardt algorithm was used in predicting the mechanical properties using the ANN. A good correlation was obtained between the experimental and predicted values with an error (%) of less than 10. The decrease in mechanical properties with the increase in replacement levels of coarse aggregates in concrete was observed in both experimental and predicted approaches. This can be attributed to poor bonding between concrete and PP aggregate owing to the development of agglomerations and the hydrophobic nature of PP. However, the strength values of 20% PP-embedded concrete specimens are closer to 0% PP-embedded concrete specimens. Therefore, 20% PP-embedded concrete specimens can be used for primary load-bearing applications to utilize plastic waste and reduce the cost of the component.

Compressive strength of light-weight concrete material made from treated wood waste as a coarse aggregate

The effect of replacing the conventional coarse aggregate with wood shavings was evaluated relative to the 28-day compressive strength of the concrete. Six groups were studied: group-1 represented the normal concrete (NC-CTRL1), group-2 (TW-CTRL2) comprised the specimens that had the replacement of the coarse aggregate with raw wood shavings, group-3, group-4, group-5, and group 6 represented the specimens that had the coarse aggregate as coated (treated) wood shavings with cement paste (group-3 and -4) and with tile adhesive paste (group-5 and -6), with and without the effect of the emulsifier, respectively. The density of the TW-CTRL2 concrete was 31.4% lighter than NC-CTRL1. However, the compressive strength of TW-CTRL2 was 75% of the NC-CTRL1, but within the acceptable limits stated in ASTM standards. The findings of this study showed a potential to use the produced concrete as concrete masonry unit when compared with the values reported in previous studies. Compared with TW-CTRL2, the compressive strength increased 45% and 20% for the coated wood shavings with cement and tile adhesive pastes, respectively. The effect of using the emulsifier in the coating process of the wood shavings increased the compressive strength by 20%, and reduced the voids of the concrete by 3%.

To Investigate the Properties of Concrete Having Partial Replacement of Fine Aggregate with Copper Slag and Coarse Aggregate with Ceramic Tile Waste

Abstract: The process of smelting copper produces copper slag as a by-product. The disposal of such a massive volume of copper slag raises environmental concerns. So, recycled copper slag can be utilised in place of fine aggregate or cement. This has several benefits, including lowering disposal costs and increasing recycling rates. In terms of coarse aggregates, their supply is a serious challenge in the construction industry. As a result, ceramic tile waste can be used as a coarse aggregate substitute. They are tough, long-lasting, and resistant to degrading forces. Ceramic tile wastes are simply leftover tiles from construction projects. Waste generated during building and demolition activities accounts for over 70% of all waste worldwide. Furthermore, approximately 60% of the waste generated during the creation of tile is discarded. As a result, discarding such a large amount of rubbish causes environmental issues. Concrete costs are lowered when they are used. The results of an experimental inquiry into the impact of partially substituting fine aggregate with copper slag and coarse aggregate with ceramic tiles waste on the strength properties of concrete are presented in this study. Utilizing 150x300mm cylindrical specimens for split tensile strength research and 150x150x150mm cubes for compressive strength testing. As the amount of ceramic waste in the mix rose, the concrete's workability, density, compressive strength, and flexural strength all decreased. The mix M5 had a compressive strength of 44.40 N/mm2 after 28 days of curing. Ceramic waste is porous and lighter than conventional coarse aggregate, resulting in lower density and strength. This study shows that ceramic waste may be utilised for both structural and non-structural purposes.

Comprehensive Characterization of Ferrochrome Slag and Ferrochrome Ash as Sustainable Materials in Construction

Ferrochrome slag (FCS) and ferrochrome ash (FCA) are by-products generated during the production of ferrochrome alloy in the ferrochrome industry. The use of these by-products as construction materials appears to be an innovative strategy that could provide numerous environmental and socio-economic benefits. However, the residual chromium present in ferrochrome by-products may have some negative effects on the surrounding environment also. In a nutshell, this study provides a thorough and critical examination of ferrochrome slag and ferrochrome ash’s suitability for construction, as well as a list of the major shortcomings that must be addressed to accomplish construction sustainability. A detailed summary of the physical, chemical, and mechanical characteristics of ferrochrome slag and ferrochrome ash was presented in the study. Ferrochrome slag from previous studies is said to exhibit better mechanical properties compared to conventional coarse aggregates which contributed to better mechanical properties of concrete. The application of ferrochrome slag as a substitute for natural sand, on the other hand, is considered to have a detrimental impact. As a reason, further research is necessary to determine the impact of replacing conventional fine aggregate with ferrochrome slag on the various mechanical and durability properties of concrete. Ferrochrome ash from previous studies can be used as a partial replacement for cement and unlike FCS, FCA is nonhazardous since no residual chromium traces were present in FCA. Furthermore, the protracted safety and effect on the surrounding environment of ferrochrome slag containing concrete in a variety of exposure conditions have to be fully examined in the near future.

Effect of Elevated Temperature on the Physical and Mechanical Properties of Crushed Clay Bricks Aggregate Concrete

In this study concrete block was produced with waste crushed clay bricks (CCB). CCB is used as a conventional coarse aggregate replacement with the range of 0, 25, 50 and 75%. Physical and mechanical properties of concrete blocks were examined at room temperature (25°C) and elevated temperatures of 400, 600 and 800°C. The results indicated that concrete specimens with 50% CCB exhibited the greatest flexural strength characteristics compared to that containing natural aggregates, whereas a slight decline indicated at the density and compressive strength. However, the specimens with 75% CCB have the highest residual strength at an elevated temperature of 800°C. Accordingly, it is suitable for load-bearing wall application when exposed to elevated temperature in confirmation to ASTM-C55. Keywords: Concrete Masonry Units; Crushed Clay Bricks; Elevated Temperature; Coarse Aggregate Replacement.

Design and strength optimization method for the production of structural lightweight concrete: An experimental investigation for the complete replacement of conventional coarse aggregates by waste rubber particles

End-of-life tires are a challenging waste because of their non-biodegradable properties, high production volume, and low utilization rate. Extensive research is currently being undertaken to look for various applications of waste tire rubber in the concrete industry to improve their utilization rate and significantly increase the uptake of this waste material. However, low strength and poor bond performance between rubber aggregates and cement matrix are hindering its application in the concrete industry. This paper introduces an innovative method of prestressing the coarser rubber aggregates (RAs) to address these challenges and limitations found in the critical literature review. Two steel mould rigs were newly designed for manufacturing the rubberized concrete (RuC). Three different mix designs containing 100% replacement of conventional coarse aggregates were prepared using (i) two different sizes of rubber particles and (ii) the addition of steel fibers. Density, SEM-EDS analysis, compressive strength, splitting tensile strength, flexural strength, and modulus of elasticity were undertaken to evaluate mechanical performances. The experimental results depict that this novel preloading method can bring a maximum of 97%, 59%, and 20% increase in compressive strength, flexural and tensile strength compared to that of the normal RuC, respectively. In addition, it provides a significant improvement in the interfacial transition zone between the matrix and RAs. This study demonstrates the efficient scientific recycling procedures in manufacturing the RuC with a maximum compressive strength of 18 MPa (density of 2000 kg/m3), which can be considered structural lightweight concrete as per ACI 213R-14 and Eurocode 2 recommendations.

Role of recycled vehicle tires quantity and size on the properties of metakaolin-based geopolymer rubberized concrete

Increasing demand for concrete construction and the consequent increase in the production of conventional Portland cement is thwarting efforts towards sustainable construction practices. This is seen in the carbon dioxide footprint caused by cement manufacturing as well as natural resources consumption. Therefore, the so-called geopolymer or alkali-activated composites using byproduct or natural materials are seen as a potential substitute for cement-based binders. Similarly, recycled rubber recovered from shredded tires has been used in concrete mixes, which in addition to the environmental benefit, offers desirable properties, e.g., improved deformability and energy dissipation capacity. Therefore, this paper investigates the influence of introducing recycled rubber in metakaolin-based geopolymer mixes on the workability, compressive behavior (stress–strain components and failure mode), flexural strength, unit weight, air content, and water absorption percentage. Seven mixes were employed for this purpose with two main variables comprising rubber size (fine, coarse, or combination of both) and replacement percentage (0%, 20%, and 40%). Recycled rubber was observed to reduce the mix workability by 4%–52.5% and 40%–62.5% when fine or coarse rubber particles were added to concrete mixes, respectively. Average compressive strength of 14.3–37.7 MPa was achieved when fine and/or coarse rubber particles replaced 20% or 40% of the conventional fine and/or coarse aggregates. Furthermore, rubberized geopolymer concrete showed more deformability than plain mixes coupled with lightweight characteristics, which are desirable in many construction applications. This indicates the suitability of the rubberized geopolymer concrete for developing low to moderate-strength concrete for non-structural and structural applications.

Exemplification of sustainable sodium silicate waste sediments as coarse aggregates in the performance evaluation of geopolymer concrete

This investigation presents the experimental studies on mechanical properties of geopolymer concrete (GPC) developed with the addition of sodium silicate waste sediments (SSW) as coarse aggregates. Conventional crushed granite coarse aggregate (CA) was replaced by SSW from the sodium silicate manufacturing plant. The GPC was developed by replacing the natural CA with SSW from 0% − 70% with a trend in exercising circular economy in the concrete. The GPC with 100% CA was used as the control specimen to compare the results of different replacement levels of SSW. A low calcium Fly ash (FA) and Ground granulated blast furnace slag (GGBS) were used as binder materials, along with sodium hydroxide and sodium silicate solutions as activator solutions. The sodium hydroxide of 4 M and sodium hydroxide to sodium silicate ratio of 1:1.5 were used in the development of the mixes. Two types of curing conditions namely, ambient and oven curing were adopted. The M30 grade design mix was used for control and CA replaced specimens. The mechanical properties such as compressive, tensile, and flexural strengths along with the elastic modulus of GPC at the ages of 7-, and 28-day were investigated. Microstructural analysis was conducted to examine the influence of SSW on the strength characteristics of GPC. The analyses were performed to evaluate the energy requirement and CO2 emission of GPC and OPCC (Ordinary Portland Cement Concrete) in the production of 1 m3 concrete based on the previous literature. The significance of the proposed research work emphasizes the utilization of waste SSW as an aggregate material for the development of GPC. Therefore, a sustainable GPC mix can be developed with lower energy requirement and CO2 emission. The results revealed that the specimens with 40% SSW cured at 60 °C produced the targeted strength of 34.6 MPa. Meanwhile, the mixes with 40% − 70% of SSW exhibited superior performance in terms of cost and eco-efficiencies.

Mechanical Properties of Concrete Incorporating Waste Glass as Replacement for Fine and Coarse Aggregate

This study investigates the effects of waste glass as a replacement for fine and coarse aggregates on the strength properties of concrete. Fine waste glass (FWG) and coarse waste glass (CWG) were utilised to replace natural fine and coarse aggregates at replacement rates of 0%, 10%, 15%, and 20%, with a constant water-to-binder (w/b) ratio of 0.5 and a mix ratio of 1:1½:3 for M25 grade. The workability of fresh concrete mix was determined with the slump test. To assess the hardened characteristics of concrete, compressive and tensile strength tests were performed at 7, 14, and 28 days’ curing ages. The results show that the workability of concrete decreases as the FWG and CWG contents in the concrete mix increase. The 28-day compressive and tensile strengths of concrete increased by 28% and 16% respectively, with the replacement of up to 15% FWG and CWG, respectively compared to the control. However, the compressive and tensile strengths of concrete reduces with further replacement of fine and coarse aggregate with waste glass. The strength properties of concrete are improved at the optimum permissible level of 15% FWG and CWG, respectively, as a substitute for conventional fine and coarse aggregates. It was concluded that using waste glass as a constituent material in concrete production is a viable option for disposing of waste glass and lowering concrete production costs.

Geopolymer Aggregate Concrete: A review from fundamentals to developments

Aggregates hold almost three-fourths volume of concrete. The tremendous increase in the growth rate of constructions has further accelerated the demand of aggregates. The utilization of aggregates to satisfy the demand has led to the inadequacy of aggregates. A unique method of developing non-conventional aggregates as a substitute of conventional coarse aggregates can be the justification of the issue. Meanwhile, considerable amount of fly ash produced from thermal power plants is disposed in landfills and ponds, creating hazard to the nature. Researchers have focused in utilizing fly ash to produce aggregates through the process of pelletization. Geopolymerization parameters such as Na2O content, slope and speed of disc pelletizer influence the properties of fly ash based pelletized aggregates. The compressive strength of geopolymer aggregate concrete depicted a higher value than concrete with conventional aggregates. The objective of this paper is to present the factors affecting the production of geopolymer aggregate concrete and the properties of these novel aggregate concrete.

Evaluation of the Structural Response of Reinforced Concrete Beams Produced with River Gravel as Coarse Aggregate in Building Construction

An increase in demand for concrete to meet global needs has been accompanied by an increase in global concerns due to an increase in demand for the non-renewable resources that are and comprise the constituents of concrete. To address these concerns and mitigate the impact of their depletion, researchers have investigated the intrinsic properties of a wide range of available materials and assessed their contribution when mixed with concrete. This paper presents the findings of an experimental study that was carried out to assess the structural response of concrete beams made with river gravel as coarse aggregate. Six reinforced beams (100 x 150 x 1100 mm) and six cubes were cast to investigate the specimens' flexural and compressive behavior. The failure modes, bending, and shear capacity were investigated in this study. According to the findings of the study, river gravel used as coarse aggregate in concrete has a roughly equivalent or slightly lower structural performance than conventional coarse aggregate, indicating the feasibility of river gravel as coarse aggregate for building construction.

Assessment of Reactive powder concrete subjected to three different sodium sulfate Concentrations: Compressive Strength, Absorption, Porosity, Microstructure, and durability

Reactive Powder Concrete (RPC) is a relatively new type of concrete material characterized by very low water-to-binder ratios (w/b), the addition of supplementary cementitious materials like silica fume (SF), and the presence of very fine aggregates instead of conventional coarse aggregates. The durability of RPC with various w/b (0.18, 0.22, and 0.26) and SF content (15%, 20%, and 25%) against external sulfate attack (ESA) at various sodium sulfate (Na2SO4) concentrations (0.35 M, 0.7 M and 1.4 M) was investigated in this study through examinations of compressive strength, expansion and mass change, microstructural characteristics, mineralogy, porosity, and sorptivity. The results indicated that: 1) owing to its improved microstructure, RPC could accommodate expansive products of ESA reactions, which can provide additional strength; 2) RPC showed very high resistance to Na2SO4 attack under the ASTM C1012 criteria; 3) considerable sulfate ingress did not result in significant expansion and strength reduction for RPC mixtures at early stages of exposure, especially for the mixtures with high initial sorptivity and high interparticle connectivity; 4) considering the coupled effect of w/b and SF content on the number of RPC characteristics, mixture with w/b = 0.22 and 20% SF content showed the best performance upon exposure to ESA.

MECHANICAL PROPERTIES AND FRACTURE PREDICTION OF CONCRETES CONTAINING OIL PALM SHELL AND EXPANDED CLAY FOR FULL REPLACEMENT OF CONVENTIONAL AGGREGATES

In order to reduce the continual depletion and exploitation of natural resources, this paper examines the mechanical properties and fracture prediction of sustainable lightweight aggregates concretes comprising agro-industrial waste or/and artificial aggregate, considering a full replacement of conventional coarse aggregate. The fresh and hardened properties are examined, from which three out of the five design mixes can achieve structural concrete specifications. It is observed that compression, tensile, and flexural strengths of the mixes exhibit a similar behaviour trend, as relatively higher values can be obtained from homogenous coarse aggregates compared to heterogeneous aggregates for different proportions of oil palm shell (OPS) and expanded clay replacement. The experimental results showed compression strength of 13 to 32 MPa, splitting tensile strength of 1.32 to 2.97 MPa and flexural strength of 1.67 to 5.24 MPa for the investigated mixes at concrete age of 28 day. Most of the mixes able to achieve structural use. Amongst the mixes, those containing expanded clay lowered the corresponding sorptivity values. Although statistics prove that the prediction models of tensile and flexural strengths can represent existing experimental findings, further investigations are recommended for a better properties forecasting of lightweight aggregate concrete containing OPS and expanded clay.

Study on mechanical properties of concrete using different types of coarse aggregates

In the construction industry over the past few decades use of concrete has increased exponentially. This has lead to scarcity of its natural ingredients (Coarse and Fine Aggregates). Hence there is a need to look for other alternatives. This research is aimed at finding suitable alternative to conventional coarse aggregates. The alternatives considered are waste granite marble chips, angular aggregate, demolished aggregate and round aggregate. Eare performed on these so as to ensure the quality of aggregates. M20 Conventional concrete is taken as reference sample and designed as per IS 10262–2009. Coarse aggregate is replaced 100% with each of the above alternatives and these mixes are also designed as per IS 10262–2009. Water cement ratio for all mixes is fixed as 0.50. Standard cubes of size 150x150x150mm were casted for all the concrete mixes, cured and tested for compression test 07, 14 and 28 days age as per IS 516–2002 (Reaffirmed 2018). The compressive strength at 28 days age obtained for reference sample-conventional is 22.35 N/mm2, waste granite chips is 22.04 N/mm2, angular is 21.33 N/mm2, demolished aggregate is 13.41 N/mm2 and round is 13.15 N/mm2 and. It is clear that waste granite aggregate is the best alternative to conventional coarse aggregate.

Effect of 6 Hour Fire on Flexural Strength of RC Beams made with 50% Coarse Aggregates from old concrete: Part 1: Normal mix

Shifting of people from villages/small cities to big cities poses a serious issue of accommodation and other associated infrastructure. For the solution of said issue, demolition of old structures to construct new high-rise buildings is opted. The demolishing waste is an additional problem for the project, particularly due to unavailability of the dumping space in many areas. A method of addressing the issue is by using it in new concrete. This research study presents an experimental investigation to check the effect of a 6-hour fire at 1000◦C on the bending resistance of reinforced concrete beams prepared by replacing 50% conventional coarse aggregate with coarse aggregate from demolished concrete. 24 RC beams of 0.9m × 0.15m × 0.15m size are cast using 1:2:4 mix and 0.54 water cement ratio. To reinforce the beams 2#4 bars in each tension and compression zones are used. Out of 24 beams, 12 are cast with all-natural coarse aggregates to compare the results. After 28-days standard curing, all beams are exposed to fire for 6 hours in purpose made oven. The beams are then left at room temperature for 24-hours followed by testing of all the beams in universal load testing machine with central point loading. Load and deflection are monitored at regular intervals. Comparison of the results with control specimen shows that the proposed beams observed 13.43% reduction in flexural strength which is quite smaller. The beams failed in shear which complies with the failure mode of normal concrete beams. Thus, the proposed material has good fire resistance when used in reinforced concrete beams.