Experimental investigation on the use of recycled aggregates in producing concrete (original) (raw)
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A Review Paper on Use of Recycled Concrete Aggregates in Concrete Manufacturing Process
Construction industry generates large amount construction & demolition waste. This waste may be in the form of debris & building materials such as broken bricks, mortar, concrete, steel. At the same time foundry industry also generates large amount of waste sand. The foundry sand is sand used for the formation of moulds essential in the casting process. After the completion of its usefulness, it is dumped in open areas or low laying areas.The waste from construction & demolition are also dumped in open land & low laying areas. This process disturbs the environment & pollutes the ground water (SayeedJaved, 1992). The reuse of this waste will not only reduce the cost of disposal along with land requirement but also be useful in environment by conserving the use of natural aggregate. Concrete is the world's second most consumed material after water, and its widespread use is the basis for urban development. It is estimated that 25 billion tonnes of concrete are manufactured each year. On the other hand over 1 billion tonnes of construction and demolition waste (C&DW) is generated every year worldwide. Crushed concrete is available nowadays in large quantities, which also results from the demolition of old structures and waste concrete from new structures. Every year, it is estimated that 2% to 10% (average of 5%) of the estimated ready mixed concrete produced is returned to the concrete plant which is also of great concern to dispose off. The use of the recycled aggregates created from construction and demolition waste in new construction has become more important over the last two decades. Waste minimization and reducing the burden on landfills is a global issue. Extensive research has been carried out worldwide on the use of recycled aggregate in concrete. This includes substantial research reports by WRAP4, NRMCA5 and RILEM6. Globally the concrete construction industry has taken a responsible attitude to ensuring its natural resources are not overexploited. The reuse of hardened concrete as aggregate is a proven technology-it can be crushed and reused as a partial replacement for natural aggregate in new concrete construction. Recycling construction waste is vital both in order to reduce the amount of open land needed for land filling and to reduce depletion of raw materials. Recycling or recovering concrete materials has two main advantages-it conserves the use of natural aggregate and the associated environmental costs of exploitation and transportation, and it preserves the use of landfill for materials which cannot be recycled. Many attempts to develop high-grade uses of construction waste, i.e., as aggregate for the manufacturing of new concrete, are made in last few decades. A decrease in the compressive strength was generally observed in all concretes in which the natural coarse aggregate was replaced with recycled aggregate prepared by the crushing of old concrete. In the current paper we are going to study the feasibility of Recycled Aggregate in concrete manufacturing when it is blended with different proportions of fly ash and admixtures. We are going to study strength characteristic of concrete made with optimum proportions of ingredients. The study will give idea for the effective use of waste concrete which benefits sustainable development by reducing the necessity of land required for dumping waste concrete. " II. LITERATURE REVIEW " They conducted an experimental investigation to study the mechanical as well as micro structural properties of recycled aggregate concrete (RAC) exposed to elevated temperature.
Recycling is the act of processing the used material for use in producing new product. The use of naturally available aggregate is getting more and more intense with the advanced development in infrastructure area. In order to reduce the usage of natural aggregate, Recycled aggregate concrete can be used as the replacement materials. Recycled aggregate concrete are consists of crushed concrete, inorganic particles processed from the materials that have been already used in the structural constructions and demolition waste. New technologies have evolved very fast to cater different difficulties in the construction industry, Production of concrete which will leave a substantial mark on the environment. The concrete is made with concrete wastes which are eco-friendly to environment is known as Recycled aggregate concrete. This thesis covers the aspect on how to choose a material for Recycled aggregate concrete. By the use of Recycled aggregate concrete it is possible to reduce the CO2 emission in atmosphere. To avoid the pollution and reuse the material, the present study is carried out. In this study the laboratory test results indicates that as the percentage of Natural Aggregate in the mixture decreases by replacing the Recycled Aggregate, the corresponding strength of these mixtures goes on decreasing, however up to the 60% replacement level, it achieves target mean strength. Hence, for the structural concrete Natural Aggregate can be replaced by the Recycled Aggregate up to 60% range. I INTRODUCTION: To achieve sustainable issue in construction area, researchers and companies focus on using waste concrete as a new construction material. It is called recycled aggregate which can be produced by concrete crusher. The aggregates are categorized by size as coarse and fine aggregate. If recycled aggregates were practically useful in construction area, two aspects would be expected. One is illustrated at the beginning of introduction; the other one is that we could reduce consumption of natural aggregate resources. Although using recycled aggregates has great opportunity to preserve healthy environment, the properties and characteristics of recycled aggregates has not been fully investigated yet. Since it is hard to standardize the characteristic of recycled aggregates, all the researchers who study recycled aggregate should perform experiment of their concrete, which will be used for recycled aggregate, to gain the characteristics of their specimens. The characteristic of recycled aggregates could be different by its parent concrete because the parent concrete was designed for its purposes such as permeable, durable and high strength concrete. For example, water to cement ratio of parent concrete will give an impact on water absorption capacity of recycled aggregates which is related to characteristics of concrete issue such as durability, permeability, strength and elastic modulus. 2 Literature Review: Limbachiya et al., (2000)[1] found that Recycled aggregate concrete had 7 to 9% lower relative density and 2 times higher water absorption than natural aggregate. According to their test results, it shown that there was no effect with the replacement of 30% coarse Recycled aggregate concrete used on the ceiling strength of concrete. It also mentioned that Recycled aggregate concrete could be used in high strength concrete mixes with the Recycled aggregate concrete content in the concrete. Bodin et al., (2002)[2] stated that decreasing of the strength of recycled concrete specimen was due to the increase of water/cement ratio that required by the preservation of workability.
The objective of this research is to investigate the workability and compressive strength of recycled aggregate concrete (RAC) for M 20, M 30 and M 40 grade of concrete with 0, 25, 50, 75 and 100 % replacement of natural aggregates with recycled concrete aggregates (RA). A total of 90 cube specimens were cast for testing compressive strength of RAC after 7 days and 28 days and comparative analysis was made. Results of slump test showed that workability of concretes decreased with increase in the percentage of recycled aggregate and the values increased with the increase in the grade of concrete due to the higher cement content in the higher-grade mix. For strength characteristics, the results showed a gradually decreasing trend in compressive strength as the percentage of recycled aggregate used in the specimens increased. The strength of recycled aggregate concrete decreases with the increase in grade without any admixture but still the use of RA up to 50 % in concrete mixture is found to have workability and compressive strength near to that of natural aggregate concrete and can be used effectively for structural concrete. For M 20, recycled aggregates up to 100 % can be utilized without any chemical admixture.
The Effect on the behavior of Concrete by using Recycled Aggregate Concrete
This research review represents the collection of data from various previous studies done on the behavior and properties of recycled aggregate concrete. Construction industry generates large amount construction & demolition waste. This waste may be in the form of debris & building materials such as broken bricks, mortar, concrete, steel. At the same time foundry industry also generates large amount of waste sand. The foundry sand is sand used for the formation of moulds essential in the casting process. After the completion of its usefulness, it is dumped in open areas or low laying areas. The waste from construction & demolition are also dumped in open land & low laying areas. This process disturbs the environment & pollutes the ground water. Recycled aggregates concrete utilizes materials from concrete and masonry constructions. Reuse of demolition waste avoids the problem of waste disposal and is also helpful in reducing the gap between demand and supply of fresh aggregate. Many researchers state that the recycled aggregates that are obtained from concrete specimen make good quality concrete. For improving the quality of recycled coarse aggregate, various surface treatment methods such as washing the recycled aggregates with water and diluted acid were investigated. Strength properties of the treated and untreated coarse aggregate were compared. The results indicated that the compressive strength of recycle aggregate is found to be less than the natural aggregate. A lot of experiments have been made to investigate the strength behaviour of recycled aggregate concrete using demolition waste. The behaviour of concrete like workability, variation of strength made with recycled aggregate is more or less similar to conventional concrete. A comparative analysis of the experimental results of the properties of fresh and hardened concrete with different replacement ratios of natural with recycled coarse aggregate is presented in the paper. Recycled aggregate was made by crushing the waste concrete of laboratory test cubes and precast concrete columns. Three types of concrete mixtures were tested: concrete made entirely with natural aggregate (NAC) as a control concrete and two types of concrete made with natural fine and recycled coarse aggregate (50% and 100% replacement of coarse recycled aggregate).
Investigation of concrete properties using recycled waste concrete aggregate
Periodicals of Engineering and Natural Sciences (PEN), 2023
There are several environmental, economic, and energy reasons why RC is gaining popularity around the world. Key environmental problems include the potential for groundwater contamination due to the washing out of fresh concrete brought back from project sites, as well as the loss of natural sources of high-quality aggregate materials. The RC concrete (RCA) impact on the fundamental characteristics of traditional concrete is investigated besides the effect of different ratio effects of water-cement (w/c). The concrete as crushed rubble obtained from several Iraqi demolition sites and landfills is utilized to examine the properties of (RCA). This work utilized sand as natural, and concrete as crushed from various sources as aggregates around Baghdad city. A total of forty-five concrete mixtures were cast into nine groups. Groups were created to examine the impact of recycled coarse aggregate (CA) quality/content, dosage of cement, and w/c ratio. Strengths of compressing and splitting, and modulus of elastic tests were conducted. The findings demonstrated that the concrete rubble (CR) may be turned into recycled aggregate (RC) and utilized in the concrete manufacturing with qualities adequate for the vast majority of structural concrete applications in Iraq. Furthermore, the concrete strength has decreased by 6% to 30%, depending on the proportion of RC utilized to replace natural aggregate and the w/c ratio.
Use of Recycled Concrete Aggregate in Construction
– Recycled aggregates comprised of crushed, graded inorganic particles processed from the materials that have been used in the constructions and demolition debris. This study aims to develop the best economic solution by use of that demolition debris as recycled aggregate in structural concrete to reduce the environmental impact, the main objective of this paper is to investigate the hardness properties of Recycled Aggregates & Recycled Concrete Aggregate including abrasion test, impact value test & water absorption test on aggregates while slump, compressive strength, tensile strength & modulus of elasticity on fresh & hard concrete, which will give a better understanding on the properties of concrete with recycled aggregates, as an substitute material to virgin coarse aggregate in structural concrete. To determining the above properties of the recycled aggregate by studying the influence of limited percentage of recycled aggregate in concrete. The Laboratory trials were conducted with the aggregate size of 10-20mm, there were total of six batches of two concrete mixes M30 with 0.42 w/c & M20 with 0.5 w/c, consist of 00%, 40% & 60% of recycled aggregate replacement. The workability of concrete will be decreased as the amount of recycled aggregate increased but in the end, is considerable in the mix as it is still under the limits. This was evaluated through standard slump test. For strength characteristics, the results showed a gradually decreasing in modulus of elasticity, tensile strength, compressive strength as the percentage of recycled aggregate used in the specimens increased but at last most of the results were satisfactory & under the limits.
Effect of Replacement of Natural Aggregates by Recycled Aggregates Used In Concrete
International Journal for Research in Applied Science and Engineering Technology, 2017
This experimental investigation is performed to investigate the used of demolished concrete for construction in concrete material. Demolished concrete occupies a large space and hence it's disposal is very important. Only a small quantity of this waste is recycled for beneficial use. The present investigation is focused on use of demolished concrete in order to reduce construction cost and resolve housing problems faced by the low income communities of the world. The demolished waste of concrete is segregated with the aid of sieving to achieve required sizes of aggregate various tests were conducted to determine the mixture properties of material before producing a new concrete. This investigation explained that the demolished concrete might be received from construction site used for making good quality concrete. The investigational analysis has been optimized to estimate the cause of compressive strength of recycled concrete for the study at 7 th and 28 th days. The compression strength concrete thus, examined was compared with strength of conventional concrete. The outcomes of investigation explained the compressive strength of concrete up to 50% coarse aggregate substitution with demolished concrete at the end of 28 days has been achieve to be comparable to the conventional concrete.
Journal of Civil Engineering and Architecture, 2016
The main purpose of this research is to study the properties of re-use different types of construction materials such as PVC (polyvinylchloride) scraps, clay brick and recycled concrete as a partial replacement of coarse aggregate. Different proportions (1%, 3%, 5% and 7%) by weight were used for PVC. scrap, (10%, 20%, 30%, and 40%) by weight were used for recycled concrete and (5%, 10%, 15%, and 20%) by weight were used for clay brick. Mechanical tests such as compressive and tensile strength tests and physical tests such as ultrasonic pulse velocity, bulk density, porosity, specific gravity and water absorption tests were done to the samples after curing in normal water for 28 days. Test results showed slightly degradation in mechanical and physical engineering properties of concrete specimens that used partial replacement of recycled concrete coarse aggregate, degradation increased with increasing of replacement but test results still closely to reference samples. Use of polyvinyl chloride in proportions not more than 5% as a partial replacement of coarse aggregates given acceptable results in comparison with reference samples but all test results degraded at 7% replacements. Test results of partial replacement of crushed brick coarse aggregates unacceptable and the range of degradation are wide because of increased (water: cement) ratio to improve the concrete workability.
Many countries in Europe, America and Asia are now relaxing their infrastructural laws to allow the use of construction and demolition waste, otherwise known as recycled aggregate, in concrete. This paper reports the basic properties of recycled fine and coarse aggregates in comparison with natural aggregates. The effects of changes in all aggregate properties on concrete are discussed. Basic concrete properties like compressive strength, flexural strength, workability etc are discussed with respect to different combination of recycled aggregate with natural aggregate. Codal guidelines of recycled aggregate in various countries are discussed together with present status of recycled aggregate in Nigeria. Copyright © IJEATR, all rights reserved. Keywords: Recycled aggregate, Natural aggregate, Sustainability, Compressive strength, Flexural strength, Workability. _____________________________________________________________________________________________
Use of Recycled Concrete Aggregate and its Influence on Strengths of Concrete
International Journal of Trend in Research and Development, Volume 4(4), ISSN: 2394-9333, 2017
In our present society the major challenges is protection of environment. Cities are suffering because of their own Construction and Demolition Waste (CDW) with serious environmental consequences. Reducing, recycling and re-using appear to be the best option. Concrete deterioration may be due to many reasons: Corrosion of enclosed metals, Chemical attack, Alkali-Aggregate reactivity, Fire, Overloaded, etc.The techniques for producing concrete using recycled aggregate obtained from CDW. Also the effects are studied on the compressive strength and flexure strength of concrete conducting various laboratory trials, replacing the natural aggregate by the recycled ones. Replacement of aggregates is done in percentage. So in this project, concrete was tested made from recycled aggregates replacing natural aggregates. Such that the recycled aggregates were sub-graded, with respect to the service life of the parent concrete.Finally, the investigation and comparison of experimental results of strengths of natural aggregate concrete and recycled aggregate concrete with the help of statistical data obtained by testing of specimen was done, as per recommended procedures by IS 516:1959.