Aggregate Replacement Research Articles

PET Granule Replacement for Fine Aggregate in Concrete and FRP-Wrapping Effect: Overview of Experimental Data and Model Development

In this study, polyethylene terephthalate (PET) was substituted for 10%, 20%, and 30% of the sand volume in concrete. Compressive, splitting tensile, and flexural strength tests were applied to the concrete samples and stress–strain graphs were obtained. It was observed that PET substitution caused a decrease in the mechanical properties of the concrete. For this reason, the concrete with the best PET substitution rate (10%) was reinforced by wrapping it with carbon fiber-reinforced polymer (CFRP) and glass fiber-reinforced polymer (GFRP), and the same experiments were repeated. It was observed that a 10% PET substitution reduced the strength of the reference concrete by about 6%. However, wrapping the PET-substituted concrete with CFRP and GFRP increased the strength by about 1.9 and 1.5 times, respectively, surpassing that of the reference sample. In addition, this study provides a comprehensive database by bringing together experimental data from studies in which PET was used as a substitute by volume or weight instead of fine aggregate in concrete. The models proposed in this study, along with previous models, were tested for applicability. Similarly, the model suggestions in the literature for fiber-reinforced polymer (FRP)-confined concrete were tested with the experimental data in this study, and their suitability for PET-substituted concrete was discussed.

The Impact of Fly Ash and Sea Sand on Strength and Durability of Concrete

Fly ash is a solid waste produced by power plants. To overcome the bad effects on the environment, fly ash is used as a substitute for cement in making concrete. Apart from that, the innovation of aggregate replacement materials in mixing concrete also has several alternatives, one of which is the use of sea sand as a substitute for fine aggregate. This research was conducted to determine the best proportion of sea sand use 10–40% with two treatments (washed and unwashed) and the use of fly ash of 20-30% on the corrosion resistance of reinforcing steel and the mechanical properties of concrete. The research results show that using up to 30% washed sea sand and 10% unwashed sea sand can increase compressive strength when compared to normal concrete. The use of up to 30% fly ash together with 20% sea sand has the same compressive strength as normal concrete. Apart from that, the use of sea sand and fly ash together has a low-risk category for reinforcing steel corrosion (10% risk of corrosion).

The Utilisation of Coconut Shell (Cocos Nucifera) as a Partial Aggregate Replacement on the Properties of Concrete in Terms of Thermal Behaviour

Green environments or environmentally friendly buildings have increasingly captured the attention of researchers. This concept involves the reuse of waste materials to enhance or create new products. Accordingly, this study aims to investigate the utilization of fine coconut shell (FCS) as a partial substitute for sand, focusing on its applications with varying percentages from 10% to 100% on the properties of concrete in terms of thermal conductivity. The initial phase of the research concentrated on characterizing the properties of fine coconut shell and sand using methods such as sieve analysis, laser diffraction sieve technique, specific gravity tests, bulk density measurements, scanning electron microscopy (SEM), and water absorption tests. Subsequently, the mechanical properties of fine coconut shell in concrete, replacing sand partially, were evaluated through slump tests, compressive strength tests, flexural strength tests, modulus of elasticity tests, splitting tensile strength tests, water absorption tests, and water permeability tests. The second phase of the study focused on exploring the low thermal conductivity applications of fine coconut shell concrete, assessed through thermal conductivity tests (k-value) and thermal resistance (r-value) calculations. Upon collecting data, a relationship analysis was conducted to determine the optimal percentage of fine coconut shell replacement. Using this optimal percentage, wall panels were constructed to assess heat penetration into buildings, and the temperature data was validated using Autodesk Ecotect software. The findings indicated that fine coconut shell particles were finer (≤ 600 μm) compared to sand (4.25 mm - 150 μm). In terms of mechanical properties, concrete containing fine coconut shell as a partial replacement for fine aggregate demonstrated superior performance to normal concrete. Moreover, the thermal conductivity values of specimens containing coconut shell were lower than those of normal concrete. In conclusion, the study determined that replacing 50% of fine aggregate with fine coconut shell was optimal, meeting British Standard requirements and aligning with previous research findings.

Experimental Study on the Characteristics of Corrosion-Induced Cracks and Steel Corrosion Depth of Carbonated Recycled Aggregate Concrete Beams

The durability of carbonated recycled aggregate concrete (C-RAC) beams is still unclear at present. In this paper, the characteristics of corrosion-induced cracks and the steel corrosion depth of C-RAC beams were investigated through the accelerated corrosion test. The results showed that when accelerating corrosion to the 40th day, compared to the non-carbonated recycled aggregate concrete (NC-RAC) beam, the corrosion-induced cracking area of the C-RAC beam with a 100% carbonated recycled coarse aggregate (C-RCA) replacement ratio decreased by 40.00%, while the total length of the corrosion-induced cracks (CCs) increased by 51.82%. The type of probability distribution for the width of the CCs on the tension side of the C-RAC beams was a lognormal distribution. Compared with the NC-RAC beam, the mean value of the width of the CCs of the C-RAC beam with a 100% C-RCA replacement ratio decreased by 66.67%, the crack width distribution was more concentrated, and the quartiles and median were all reduced. With an increase in the C-RCA replacement ratio, the fractal dimension and the scale coefficient of CCs on the tension side of the beams showed an approximate trend of first increasing and then decreasing. The distribution of the corrosion depth of longitudinal tensile steel bars in the C-RAC beams was a mainly normal distribution. When the C-RCA replacement ratio increased from 30% to 100%, the mean value of the corrosion depth of the longitudinal tensile steel bars decreased by 33.46%, and the trend of changes in the quartiles and medians was basically the same as the trend of changes in the mean value. The research results can provide some reference for promoting the engineering application of C-RAC beams.

Investigation Report on Characteristics Strength Partial Replacement of Fine Aggregate with Copper Slag and Granite Powder

Concrete is one of the most widely used construction materials, consisting of cement, fine aggregates, coarse aggregates, and water. Traditionally, Ordinary Portland Cement (OPC), river sand, and Hard Broken Granite (HBG) stone are used in concrete production. However, the over-extraction of these natural resources has led to environmental concerns and increased costs. This has created a need for sustainable alternatives that maintain concrete’s quality and performance. This study investigates the partial replacement of fine aggregates with copper slag and granite powder in M25 grade concrete. Copper slag, a by-product of copper smelting, and granite powder, obtained during granite stone cutting, possess physical and chemical properties that make them suitable for concrete. Additionally, Pozzolana Portland Cement (PPC) is examined as a sustainable alternative to OPC. PPC, with its pozzolanic characteristics, enhances workability, chemical resistance, and long- term strength while reducing the carbon footprint. The research evaluates the mechanical and chemical properties of concrete incorporating PPC, copper slag, and granite powder. The study also highlights the environmental and economic benefits, demonstrating how these materials can contribute to sustainable construction practices. By promoting the use of industrial by-products and alternative binders, this research aims to develop high-performance, eco-friendly concrete suitable for modern construction needs. Keywords: Concrete, sustainable construction, fine aggregate replacement, copper slag, granite powder, Pozzolana Portland Cement (PPC), M25 grade concrete, industrial by-products, environmental sustainability.

Laboratory Evaluation of Mechanical Properties and Noise Absorption in Magnetite-Enhanced Concrete for Pavement Applications

This paper aims to evaluate the effects of incorporating magnetite as an aggregate in concrete mixtures and as a partial replacement for Portland cement in standard mortar mixtures, focusing on performance and mechanical properties. Noise pollution from cement concrete pavements has become a significant concern for residents, making it a priority to implement effective measures to reduce traffic noise pollution. The primary goal of this research is to explore the relationship between mixture design variables with magnetite aggregates as a partial replacement for Portland cement in concrete pavement and the mixture's acoustic performance. Samples with 0, 10, 20, 30, 40, and 50% replacement of aggregates with magnetite sand were prepared initially. Subsequently, Portland cement was replaced with 0, 1, 2, 3.5, 5, 7.5, 10, 15, and 20% magnetite concentrate powder in standard mortar. Routine tests, such as slump, density, and flow table, were conducted on fresh concrete and mortar. Additionally, compressive strength, flexural strength, water absorption, electrical resistance, and impedance tube tests were performed on the concrete and mortar mixes. The impedance tube measurements demonstrated an increase in the sound absorption coefficient for concrete incorporating magnetite compared to the reference concrete. Among the tested concrete samples, the one containing 50% magnetite as aggregate exhibited the highest sound absorption coefficient, reaching a maximum value of 0.1 within the frequency range of 315 to 400Hz. This value was 2.5 times higher than the maximum sound absorption coefficient of the reference concrete.

Effect of oxidation of End-of-Life Tire Rubber as Aggregate Substitute in Cement Mortars.

In this paper the possible use of end-of-life tire rubber as a substitute for aggregate in cement mortars was explored. The aim of this paper was to investigate the effect of rubber surface modification by acidic treatment on the final properties of mortars. In fact, through treatment with sulfuric acid at moderate concentrations, a significant improvement in rubber wettability and interaction with cement has been observed. The compressive strength of mortars containing 15%w treated rubber as a replacement of natural aggregate is comparable to those of standard mortars. This suggests that surface modification of rubber plays a very important role in the possible integration of end-of-life tire rubber in mortar and concrete. The results presented in this paper confirm that recycling in mortar and concrete is a promising way for improving rubber waste management and sustainable innovation in the construction industry.

Effect of Replacing Natural Aggregate with Plastic Aggregate on the Mechanical Properties of Concrete-Review

Humans are consuming vast quantities of plastic across various types, leading to significant challenges in decomposition and the subsequent generation of extensive plastic waste, posing a significant threat to the environment. To address this issue, researchers are actively exploring methods to minimize plastic waste and mitigate its widespread impact by incorporating it into concrete. This not only enhances concrete's durability but also reduces costs. This paper provides an overview of published research on the utilization of waste plastic in concrete. It reviews the efforts of numerous researchers in valorizing plastic waste in concrete, exploring different forms such as partial replacement of fine and coarse aggregate, as well as fibers, and examines their effects on the fresh, mechanical, and durability properties of concrete. The research findings indicate promising possibilities for recycling plastic waste in concrete. However, there is scope to investigate the combined utilization of plastic as both aggregate and fiber in concrete, potentially enabling the recovery of additional quantities of plastic waste. Furthermore, the study emphasizes the importance of employing scanning electron microscopy (SEM) to analyze changes occurring within the concrete.

EXPERIMENTAL STUDY OF CONCRETE AS PARTIAL REPLACEMENT OF COARSE AGGREGATE BY SILICA SLAG

Aggregate is a key component of concrete, greatly impacting its volume and influencing its mechanical strength, durability, and serviceability. This study examines using silica slag, an industrial by-product waste, as a partial replacement for coarse aggregate (Recycled Brick Chips) in concrete. It assesses concrete properties with silica slag replacing recycled brick chips at 0%, 20%, 40%, and 60%. The findings show that adding silica slag with recycled brick chips enhances both compressive and tensile strengths. Concrete mixes, prepared with superplasticizer (ASTM C-494: Type A & F), achieved improved workability while maintaining the required water-cement ratio. Various mechanical properties of silica slag, such as impact resistance, specific gravity, unit weight, void ratio, and water absorption, were thoroughly tested. The study reveals that a 40% replacement of coarse aggregate with silica slag results in optimal compressive strength, around 18 MPa. This indicates that concrete incorporating recycled brick chips and silica slag can achieve moderate compressive strength and meet structural requirements effectively to achieve sustainable development.

Mortars produced with recycled aggregates from construction and demolition waste – analysis and construction site application

The valorisation of construction and demolition waste (CDW) as secondary raw material is an important step towards enhancing sustainability in the construction sector, combining environmental benefits with circular economy and sustainable management.The aim of this work is to analyse several mortars produced with different percentages of replacement of natural aggregates (NA) by recycled aggregates (RA) and propose a mix design methodology. First, an extensive literature review was performed and several studies conducted in recent years have been compiled, focusing on RA produced from CDW and incorporated as recycled fine aggregates in mortar matrices. Several properties have been analysed, such as: compressive, flexural and bond strengths, Young’s modulus, capillarity, and shrinkage. Results are discussed, in order to characterize: (i) the binder paste, considering the combination of binders and the respective water-binder and binder-aggregates ratios; and (ii) the different RA and respective proportions (through replacement ratio), quantifying the respective influences on mechanical and durability properties. Subsequently, a methodology is proposed that integrates the aforementioned parameters, thereby enabling the design of mortars with different binders, RA and proportions, tailored to the specific requirements of each application.It has been concluded that, depending on the binder performance (mainly resultant of binder type, combined with its proportion, and the water-binder ratio), RA can have variable influence on the mortar properties. Furthermore, by dividing the mortars under study into groups defined by Feret coefficient intervals according to the binder used and associating the RA with correction coefficients that do not exceed 0.15 per percentage of incorporated RA, it is possible to design the mortar mix according to the desired mechanical properties.

Enhancing the Mechanical Properties of Crumb Rubber Concrete through Polypropylene Mixing via a Pre-Mixing Technique

The utilization of waste tires as aggregates in sustainable concrete production has undergone extensive research over the past several years. However, incorporating crumb tires has been discovered to lead to a reduction in the compressive strength of concrete. This paper introduces a novel technique aimed at enhancing bonding conditions and mechanical properties of rubberized concrete (RuC). The approach involves blending a thermoplastic material (such as polypropylene), tire crumb, and cement as a mineral additive, followed by heat treatment of the mixture. This new method for creating a mixture of plastic rubber particles before adding rubber to concrete is called the pre-mixing technique. By adjusting the plastic component, additive composition, or their mixing ratios, the recuperation of strength in RuC can be enhanced. Compression and stress-strain tests demonstrated that the incorporation of these new synthetic compounds improved compressive strength. Furthermore, properties such as toughness index, ultimate strain, and flexural strength were also elevated. Scanning electron microscope (SEM) results depicted an improved bonding condition in the interfacial transition zone (ITZ) between cement paste and the amalgamated rubber-plastic particles, as opposed to non-modified rubber particles. A strength recovery factor was introduced in which a better evaluation of using rubber and modified rubber on the related strength could be done. The study also proposes a mechanical model for the evaluated rubber concretes, exhibiting minimal error. The investigation revealed that replacing 25% of fine aggregate with pre-mixed rubber particles resulted in a significant 60.4% increase in compressive strength. The highest compressive strength recovery, at 52%, was observed when 10% of fine aggregate was replaced with pre-mixed rubber. Furthermore, the toughness index exhibited a notable improvement of 68% and 33% for 15% and 25% replacement of fine aggregate with pre-mixed rubber, respectively.

Investigating the Dynamic Behavior and Tensile Properties of Coal Gangue Shotcrete Under Impact Loading Conditions SHPB Device

Shotcrete is the primary support material for coal mine tunnel linings and is often subjected to dynamic loads such as blasting and impact. To promote the resource utilization of coal gangue (CG), this study incorporated it into shotcrete and investigated the dynamic mechanical properties of coal gangue shotcrete (CGSC) at different coal gangue aggregate (CGA) replacement ratios. Impact tensile splitting tests were conducted using a split Hopkinson pressure bar (SHPB) device, and the specimen failure process was recorded with a high-speed camera. The results showed that the dynamic tensile splitting strength (DSTS) and energy absorption of CGSC exhibit a significant strain rate effect, with the strain rate sensitivity of DSTS decreasing as the CGA replacement ratio increases. As the strain rate increases, the elastic limit stress of the specimens rises, and the failure mode tends to become more fragmented. Based on energy theory, this paper establishes a dynamic tensile splitting strength model for CGSC, providing theoretical support for its application in engineering.

Utilization of Steel Slag as Partial Replacement of Fine Aggregate Material in Concrete

Concrete is the most used building material in the world. As a sustainable approach in this project explores the potential benefits of incorporating steel slag sand in concrete mixtures. The objective is to study the mineralogical properties of cement, steel slag to study the strength parameter like compressive strength at 7, 14, 28 days for all mix proportions. This project investigates the utilization of the replacement of fine aggregate with steel slag sand in concrete mixes. The study evaluates the impact of these components on the mechanical properties of concrete through compression tests conducted over varying time intervals. Results indicate that as the proportion of steel slag sand increase, there is a corresponding enhancement in compressive strengths of the concrete mixes. Mix 5, containing the highest proportions of these components with 50% M- Sand and Steel slag sand, consistently demonstrates superior mechanical properties compared to other mixes, showcasing an impressive increase in compressive strengths. This highlights the effectiveness of finer particle sizes and improved packing density.

Comparative study on Conventional and Geopolymer Concrete with Partial Replacement of Fine Aggregates using Hemp Hurds

The study highlights that hemp hurd, used as a partial replacement for fine aggregates in concrete (5%-15%), improves workability and promotes sustainability by reducing natural aggregate demand. While compressive strength moderately decreases, tensile strength remains minimally affected at lower replacement levels, making hemp hurd a viable eco-friendly alternative for sustainable construction practices.

Evaluating the effect of reclaimed asphalt pavement on rubberized hot mix asphalt in pilot projects

The study goal is to evaluate the use of up to 10 % reclaimed asphalt pavement (RAP) by aggregate replacement in rubberized hot mix asphalt-gap graded RHMA-G mixes to identify any significant potential problems for durability. Five pilot projects were built, each including a control RHMA-G (without RAP) and an RHMA-G with 10 % RAP. The mixes were sampled during production and evaluated using volumetric assessment, and performance related tests including stiffness, four-point bending fatigue resistance, fracture resistance measured with the IDEAL cracking test, and rutting resistance. Mix testing results indicate that the addition of 10 % RAP had minor effects on the mechanical properties. With a few exceptions related to the total binder content of the mixes, the effect of the RAP addition was negligible compared to normal production variability. Modeling with CalME, Caltrans mechanistic-empirical asphalt pavement design software and four-point bending testing results, indicated that RAP addition effects on pavement cracking performance were either negligible or comparable to mix-to-mix RHMA-G variability. Regarding constructability, RAP addition did not create any problems. The life cycle assessment completed in the study indicates that the addition of 10 % RAP to the RHMA-G can reduce the greenhouse gasses emissions associated with the RHMA-G production (cradle-to-gate) by up to 5 %.

Assessment and modelling of the mechanical strength of roller-compacted concrete incorporating recycled asphalt pavement

Integrating recycled asphalt pavement (RAP) into roller-compacted concrete (RCC) as a replacement for natural aggregates has recently emerged as a sustainable practice with significant environmental benefits. This study investigates the mechanical properties of RCC incorporating RAP aggregates, with a focus on developing a predictive model for its flexural and split tensile strengths. RCC mixtures with varying RAP content were developed and tested for compressive, split tensile, and flexural strengths. The results revealed a decline in composite performance with an increased RAP level. Nevertheless, mechanical strength met standard requirements for replacement rates of up to 60%. A new model was then developed, considering RAP rate alongside compressive strength, to predict the flexural and split tensile strengths of RCC. Existing models for conventional concrete were also evaluated for their applicability to RCC mixtures containing RAP. The proposed model demonstrated close alignment with experimental data from this study and other studies. It exhibited the lowest root mean square error, which confirms its accuracy in predicting the mechanical properties of RCC with RAP. This model provides a valuable tool for practitioners to estimate key parameters for designing pavement made with this composite.

The Performance of Waste Marble Instead of Coarse Aggregate

Now a days we are faced with an important consumption and a growing need for aggregates because of the growth in industrial production, this situation has led to a fast decrease of available resources. On the other hand, a high volume of marble production has generated a considerable amount of waste materials; almost 70%of this mineral gets wasted in the mining processing and polishing stages which have a serious impact on the environment. The processing waste is dumped and threatening the aquifer. Therefore, it has become necessary to reuse these wastes particularly in the manufacture of concrete products for construction purposes. This experimental study presents the variation in the strength of concrete when replacing aggregates by waste marble from 0% to 100% in steps of 25%, 50%, 75% & 100%. M25 grade of concrete were taken for study of slump value is reducing for more % of replacing the stone dust. The compressive strength of concrete cubes at the age of 7, 14 and 28 days were obtained at room temperature. From test result it was found that the maximum compressive strength is obtained only at 50% replacement of coarse aggregate by waste marble at room temperature. This result gives a clear picture that waste marble can be utilized in concrete mixtures as a good substitute for coarse aggregate giving higher strength.

Pervious Concrete Incorporating Manufacturing Sand as a Partial Replacement for Coarse Aggregate

Pervious concrete has recently acquired popularity as a low-impact development strategy in pavements due to its structural, economic, and road-user benefits. The use of a single cement replacement material improved the performance of pervious concrete compared to replacing cement with fly ash or using cement alone. The most effective way for increasing the mechanical, hydraulic, and durability performance of pervious concrete was to replace both cement and aggregates with fly ash and produced sand. Replacement of 25% FA with cement was considered viable for cement replacement, while replacement of coarse aggregate with M-sand by 5%, 10%, or 15% was considered practical for aggregate replacement. The PC specimen had a cube size of 150mm x 150mm x 150mm and was cured in water for 7, 14, 28 days. The compressive strength test is performed in a laboratory after curing. The compressive strength of the pervious concrete is then compared to that of the M15 grade of concrete. The PC specimens had cylinder dimensions of 150mm dia by 300mm height and were cured in water for 28 days. Permeability testing is performed in a laboratory after curing. Key Words: Pervious Concrete (PC), Fly ash (FA), Manufacturing sand (M- Sand), Compressive strength, Permeability.

Utilization of copper slag as fine sand replacement in concrete: a response surface methodology approach

The utilization of industrial by-products in concrete production has gained significant attention due to its potential environmental and economic benefits. The increasing demand for sustainable construction materials has prompted researchers to explore alternative options that mitigate environmental concerns while maintaining desirable mechanical properties of concrete. This research paper investigates, the feasibility of utilizing copper slag as a partial replacement for fine aggregate in concrete through a systematic experimental study using response surface methodology (RSM). The study encompasses the optimization of concrete mix proportions by considering the varying levels of copper slag content (20%, 30%, and 40%), water-cement ratio (0.35, 0.40, and 0.45), and curing days (7, 14 and 28 days). Through a series of comprehensive laboratory experiments (RSM designed) and statistical analyses, this paper presents developed mathematical models, response surface plots, and contour plots and optimization of dosage of input variables for maximum compressive strength of the concrete. Results revels that curing days having strong influence on performance of compressive strength. The optimization study shows the optimal dosage for maximum performance of compressive strength was copper slag 35.90%, water-cement 0.38 and curing days 27.55 (approx. 28) days, the corresponding maximum compressive strength was 59.29 MPa. The utilization of copper slag as a replacement for fine aggregate in concrete not only addresses the issue of waste disposal but also contributes to resource conservation and reduces the carbon footprint associated with traditional construction practices.

Application of Waste Bakelite as a Partial Re-placement of Fine Aggregate: Review

Application of Waste Bakelite as a Partial Re-placement of Fine Aggregate: Review