On Properties of Recycled Coarse Aggregate from Repeatedly Recycling Waste Concrete

2011 ◽  
Vol 368-373 ◽  
pp. 2185-2188
Author(s):  
Ping Hua Zhu ◽  
Xin Jie Wang ◽  
Jin Cai Feng
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Fine Aggregate ◽  
Recycled Coarse Aggregate ◽  
Coarse Aggregates ◽  
Recycled Fine Aggregate ◽  
Waste Concrete

The properties of recycled coarsee aggregates from repeatedly recycling waste concrete were determined. In this study, five series of concrete mixtures using coarse and fine natural aggregates were prepared, which have the same objective slump value from 35mm to 50mm and different compressive strengths ranging from 25MPa to 60 MPa. These five concretes were crushed, sieved, washed with water, hot treatmented at 300°C before they were used as recycled aggregates. After that, recycled aggregate concrete (RAC) was produced with an objectively compressive strength of 30MPa, in which the recycled coarse aggregate was used as 30%, 70% and 90% replacements of natural coarse aggregate and recycled fine aggregate as 10%, 20%, and 30% replacements of natural fine aggregate. After that, these recycled concretes were used as second recycled aggregates to produce RAC with the same objectively compressive strength of 30MPa. The physical properties of coarse aggregates including apparent density, water absorption, attached mortar content and crushing value were tested and their mineral characteristics were analyzed. The results showed that the quality of recycled coarse aggregates from twicely recycling waste concrete reached the requirements from structural concrete.

scholarly journals Effect of Recycled Aggregates on Strength and performance of Recylced Aggregate Concrete

2020 ◽  
Vol 184 ◽  
pp. 01085
Author(s):  
Dr.V. Mallikarjuna Reddy ◽  
M. Manikanta Sai Swaroop
Keyword(s):  
Coarse Aggregate ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Fine Aggregate ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Recycled Fine Aggregate ◽  
The Difference ◽  
And Performance

This study is taken up to utilise the recycled coarse aggregate and recycled fine aggregate as replacement of natural aggregate in concrete mix. It is required to find the percentage of recycled coarse aggragate and recycled fine aggregate, as the strength of concrete can not be achieved by using higher percentaged. The purpose of study is to compare between recycled coarse aggregate and recycled fine aggregate with natural coarse aggregate and sand in terms of specific gravity, water absorption, particle size distribution. Further, this stydy will also consider the difference between the performance of Recycled Aggregate Concrete for different percentages of recycled coarse aggregate and recycled fine aggregate i.e for 0%, 10%, 15%, 20%, 25%, 30%, 35% replacement. The present study is an experimental investigation on the behaviour of recycled aggregate concrete (coarse& fine aggregates) with respect to the strength and performance.

scholarly journals Preliminary Analysis of the Use of Construction Waste to Replace Conventional Aggregates in Concrete

Buildings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 81
Author(s):  
Fernando A. N. Silva ◽  
João M. P. Q. Delgado ◽  
António C. Azevedo ◽  
António G. B. Lima ◽  
Castorina S. Vieira
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Recycled Aggregate Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Fine Aggregate ◽  
Demolition Waste ◽  
Fine Aggregates ◽  
Mechanical Strengths

This work aims to study the influence of using construction and demolition waste in the replacement of coarse and fine aggregate to produce recycled aggregate concrete (RAC). A moderate compressive strength concrete made with usual fine and coarse aggregate was used as a benchmark material. Compressive and split tensile tests were performed using 120 cylindrical concrete specimens with 150 mm diameter and 300 mm length. Four-point flexural tests in reinforced beams made with conventional concrete and RAC were performed. The results obtained showed that the use of recycled fine aggregates, in both percentages of substitution investigated—50% and 100%— did not generate any deleterious influence on the values of compressive strength and split tensile strength of the RACs produced. Tin fact, the mechanical strengths of RACs produced with recycled fine aggregate were equal or higher than those from the reference concrete. The same behavior was not observed, however, when the recycled coarse aggregate was used. For this case, decreases in concrete mechanical strengths were observed, especially in compressive strength, with values around 35% lower when compared to the reference concrete. Tensile mechanical tests results confirmed the excellent behavior of all RACs made with replacement of usual fine aggregates by recycled. Bending tests performed in reinforced RAC beams had as objective to evaluate the deformation profile of the beams. The obtained results showed that RAC beams with full replacement of usual fine aggregate by the recycled aggregates have presented little changes in the global behavior, an aspect that encourages its use.

scholarly journals Concrete produced with recycled aggregates

2012 ◽  
Vol 5 (5) ◽  
pp. 692-701 ◽  
Author(s):  
J. J. L. Tenório ◽  
P. C. C. Gomes ◽  
C. C. Rodrigues ◽  
T. F. F. de Alencar
Keyword(s):  
Coarse Aggregate ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Hardened Concrete ◽  
Specific Mass ◽  
River Sand ◽  
Recycled Coarse Aggregate ◽  
Coarse Aggregates ◽  
Natural Aggregates

This paper presents the analysis of the mechanical and durable properties of recycled aggregate concrete (RAC) for using in concrete. The porosity of recycled coarse aggregates is known to influence the fresh and hardened concrete properties and these properties are related to the specific mass of the recycled coarse aggregates, which directly influences the mechanical properties of the concrete. The recycled aggregates were obtained from construction and demolition wastes (CDW), which were divided into recycled sand (fine) and coarse aggregates. Besides this, a recycled coarse aggregate of a specific mass with a greater density was obtained by mixing the recycled aggregates of the CDW with the recycled aggregates of concrete wastes (CW). The concrete was produced in laboratory by combining three water-cement ratios, the ratios were used in agreement with NBR 6118 for structural concretes, with each recycled coarse aggregates and recycled sand or river sand, and the reference concrete was produced with natural aggregates. It was observed that recycled aggregates can be used in concrete with properties for structural concrete. In general, the use of recycled coarse aggregate in combination with recycled sand did not provide good results; but when the less porous was used, or the recycled coarse aggregate of a specific mass with a greater density, the properties of the concrete showed better results. Some RAC reached bigger strengths than the reference concrete.

Experimental Investigation for the Influence of Recycled Aggregate Replacement Content on Tension-Compression Strength

2015 ◽  
Vol 744-746 ◽  
pp. 1412-1415 ◽  
Author(s):  
Zong Ming Jia ◽  
Qing Han ◽  
Ming Hao Liu
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Splitting Tensile Strength ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Fine Aggregate ◽  
Recycled Fine Aggregate ◽  
Strength Formula

Designing recycled concrete mixture proportion of different recycled coarse and fine aggregate replacement content by pulp content ,then testing compressive strength and splitting tensile strength. The text results show that: With the increasing of recycled aggregate content , the compressive strength and splitting tensile strength of recycled aggregate concrete trended to decrease. Compared to recycled coarse aggregate, recycled fine aggregate impact on the properties of recycled concrete is greater. Establishing the compressive strength and splitting tensile strength formula of recycled concrete based on a lot of experimental results.

scholarly journals Degradation Resistance and Reliability Analysis of Recycled Aggregate Concrete in a Sulfate Environment

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Hui Cao ◽  
Lifeng Zhao ◽  
Chenggong Lu ◽  
Lijuan Guan ◽  
Hongxia Qiao ◽  
...  
Keyword(s):  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Coarse Aggregate ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Fine Aggregate ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Recycled Fine Aggregate ◽  
Dynamic Modulus Of Elasticity

Resistance to sulfate degradation is an important index used to measure concrete’s durability. In this study, recycled aggregate concrete (RAC) with a 0%, 30%, and 50% recycled coarse aggregate substitution rate and a 0% and 15% recycled fine aggregate replacement rate was used as the research object, and its degradation resistance was evaluated by the mass loss rate and the relative dynamic modulus of elasticity. The degradation products were studied and analyzed with SEM scanning electron microscopy and XRD phase analysis. The relative dynamic modulus of elasticity was selected as the degradation index, the RAC concrete’s degradation resistance was modeled by Wiener, and the reliability curve was obtained. The results showed that expansion products, such as gypsum and Ettringite, were produced in RAC concrete in a dry-wet sulfate cycling environment, and such defects as pores and voids were filled in the initial stage. The stress the expansion products exerted in the later stage caused the concrete to crack and peel, which demonstrated that the fluctuation law of mass and the dynamic elastic modulus increased first and then decreased. The recycled coarse aggregate substitution ratio’s effect on RAC concrete is higher than that of recycled fine aggregate. The reliability curve established by the Wiener model can reflect the reliability of RAC concrete under different cycles well and can obtain RAC concrete’s sulfate degradation resistance life with different aggregate substitution rates.

scholarly journals Effect of Recycled Coarse Aggregate and Bagasse Ash on Two-Stage Concrete

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 556
Author(s):  
Muhammad Faisal Javed ◽  
Afaq Ahmad Durrani ◽  
Sardar Kashif Ur Rehman ◽  
Fahid Aslam ◽  
Hisham Alabduljabbar ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Construction Material ◽  
Strength Reduction ◽  
Recycled Aggregate ◽  
Two Stage ◽  
Conventional Concrete ◽  
Recycled Coarse Aggregate ◽  
Coarse Aggregates

Numerous research studies have been conducted to improve the weak properties of recycled aggregate as a construction material over the last few decades. In two-stage concrete (TSC), coarse aggregates are placed in formwork, and then grout is injected with high pressure to fill up the voids between the coarse aggregates. In this experimental research, TSC was made with 100% recycled coarse aggregate (RCA). Ten percent and twenty percent bagasse ash was used as a fractional substitution of cement along with the RCA. Conventional concrete with 100% natural coarse aggregate (NCA) and 100% RCA was made to determine compressive strength only. Compressive strength reduction in the TSC was 14.36% when 100% RCA was used. Tensile strength in the TSC decreased when 100% RCA was used. The increase in compressive strength was 8.47% when 20% bagasse ash was used compared to the TSC mix that had 100% RCA. The compressive strength of the TSC at 250 °C was also determined to find the reduction in strength at high temperature. Moreover, the compressive and tensile strength of the TSC that had RCA was improved by the addition of bagasse ash.

scholarly journals Effect of Recycled Coarse Aggregates in Properties of Concrete

2008 ◽  
Vol 3 (4) ◽  
pp. 130-137 ◽  
Author(s):  
R Kumutha ◽  
K Vijai
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Modulus Of Elasticity ◽  
Coarse Aggregate ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Split Tensile Strength ◽  
Coarse Aggregates ◽  
The Cost

The properties of concrete containing coarse recycled aggregates were investigated. Laboratory trials were conducted to investigate the possibility of using recycled aggregates from the demolition wastes available locally as the replacement of natural coarse aggregates in concrete. A series of tests were carried out to determine the density, compressive strength, split tensile strength, flexural strength and modulus of elasticity of concrete with and without recycled aggregates. The water cement ratio was kept constant for all the mixes. The coarse aggregate in concrete was replaced with 0%, 20%, 40%, 60%, 80% and 100% recycled coarse aggregates. The test results indicated that the replacement of natural coarse aggregates by recycled aggregates up to 40% had little effect on the compressive strength, but higher levels of replacement reduced the compressive strength. A replacement level of 100% causes a reduction of 28% in compressive strength, 36% in split tensile strength and 50% in flexural strength. For strength characteristics, the results showed a gradual decrease in compressive strength, split tensile strength, flexural strength and modulus of elasticity as the percentage of recycled aggregate used in the specimens increased. 100% replacement of natural coarse aggregate by recycled aggregate resulted in 43% savings in the cost of coarse aggregates and 9% savings in the cost of concrete.

Investigation of the mechanical properties of concrete containing recycled aggregate and scrap crumb rubber and polypropylene fibers

2020 ◽  
pp. 147776062097750
Author(s):  
Moein Khoshroo ◽  
Ali Akbar Shirzadi Javid ◽  
Nima Rajabi Bakhshandeh ◽  
Mohamad Shalchiyan
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Polypropylene Fiber ◽  
Crumb Rubber ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Fine Aggregate ◽  
Mixture Ratio ◽  
Coarse Aggregates

In this study, the effect of using crumb rubber and recycled aggregates on the mechanical properties of concrete has been evaluated as areplacement of fine and coarse aggregates In order to add the admixtures and evaluate their combined effect, 20 different types of concrete mixture ratio were prepared. The results indicated that in those samples containing crumb rubber and recycled aggregates the compressive strength is reduced and adding fiber up to 0.1%. to these concrete samples can improve the compressive strength Also, the tensile strength of the samples mixed with crumb rubber and recycled aggregates were decreased, and with the addition of propylene fiber up to 0.4%. the tensile strength slightly increased Moreover by adding the crumb rubber to the samples the elasticity modulus was reduced but by adding fiber to samples about 0.1% and 0.2.% the modulus of elasticity of concrete in all samples were increased. According to the results, it can be said that using the combination of 5% of crumb rubber as a replacement of fine aggregate, and the combination of 35% of recycled aggregates as a replacement of coarse aggregate, and also by adding 0.1% polypropylene fiber in volumetric percentage of concrete along with adding 7% of micro silica as a replacement of cement led to the best effect on the mechanical properties of concrete.

Experimental Research on Main Properties of New Recycled Coarse Aggregate Concrete

2011 ◽  
Vol 261-263 ◽  
pp. 19-23 ◽  
Author(s):  
Da Xing Qian ◽  
Ying Wei Yun ◽  
Ii Young Jang ◽  
Jong Hoe Kim
Keyword(s):  
Concrete Beam ◽  
Coarse Aggregate ◽  
Economic Benefits ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Secondary Process ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Waste Concrete

Recently reutilization of waste concrete becomes one of the hottest issues in civil engineering field throughout the world. However, most of the concerned research focuses on the RCA (recycled coarse aggregate) by simply crushing waste concrete. In this paper shucking technique is developed to secondary process the simply crushing waste concrete for improving the performance of RCA concrete. Test has been done to demonstrate that performances such as strength, elastic modulus et al. of shucking RCA concrete is better than those of common recycled concrete. Simultaneously, beam specimens are made to test the flexural behavior of shucking RCA concrete. Results showed that the deflection of shucking RCA concrete beam is approximately same with that of natural coarse aggregate concrete beam, which solves current problem that recycled aggregate concrete beam has bigger deflection than common concrete beam. The new shucking technique developed in this paper has many advantages to be applied in practical engineering and it has obvious economic benefits and social effect.

scholarly journals Mechanical Properties of Geopolymer Concrete Made With Partial Replacement of Coarse Aggregate by Recycled Aggregate

2019 ◽  
Vol 9 (1) ◽  
pp. 2301-2304 ◽  
Keyword(s):  
Mechanical Properties ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Coarse Aggregate ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Partial Replacement ◽  
Geopolymer Concrete ◽  
Recycled Coarse Aggregate ◽  
Coarse Aggregates

Construction is the one the fast growing field in the worldwide. There are many environmental issues connected with the manufacture of OPC, at the same time availability of natural coarse aggregate is getting reduced. Geopolymer binder and recycled aggregates are promising alternatives for OPC and natural coarse aggregates. It is produced by the chemical action of inorganic molecules and made up of Fly Ash, GGBS, fine aggregate, coarse aggregate and an alkaline solution of sodium hydroxide and sodium silicate. 10 M sodium hydroxide and sodium silicate alkali activators are used to synthesis the geopolymer in this study. Recycled aggregates are obtained from the construction demolished waste. The main focus of this work is to find out the mechanical properties of geopolymer concrete of grade G40 when natural coarse aggregate(NCA) is replaced by recycled coarse aggregate in various proportions such as 0%, 10%, 20%, 30%,40% and 50% and also to compare the results of geopolymer concrete made with recycled coarse aggregates(RAGPC) with geopolymer concrete of natural coarse aggregate(GPC) and controlled concrete manufactured with recycled aggregates(RAC) and controlled concrete of natural coarse aggregates(CC) of respective grade. It has been observed that the mechanical properties are enhanced in geopolymer concrete, both in natural coarse aggregate and recycled coarse aggregate up to 30% replacement when it is compared with the same grade of controlled concrete.

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