Mechanical Behaviors of Structural Concrete Using Recycled Aggregates from Repeatedly Recycling Waste Concrete

2012 ◽  
Vol 450-451 ◽  
pp. 1379-1382 ◽  
Author(s):  
Jin Cai Feng ◽  
Ping Hua Zhu ◽  
Qun Xia

This paper reports an expermiental study on mechanical behaviors of structural concrete using recycled aggregates from repeatedly recycling waste concrete. Five series of natural aggregate concretes with compressive strengths of 25MPa, 30MPa, 40MPa, 50MPa and 60MPa were used as recycled coarse and fine aggregates to produce recycled concrete with an objective compressive strength of 30MPa after they were cured for 28d. These recycled concretes were used as aggregates to produce concrete with the same objective compressive strength of 30MPa. The cycles were carried on until the indices evaluating the quality of recycled coarse or fine aggregate exceeded the tolerance. The mechanical behaviors of these concrete were tested. The results indicates that that with the increase of the cyclic number, the mechanical properties of recycled concrete, including compressive strength, tensile splitting strength, modulus of elasticity, gradually stabilize after obviously decreaing in the first instance.

2014 ◽  
Vol 665 ◽  
pp. 163-166
Author(s):  
Ping Hua Zhu ◽  
Fei Fei Xie ◽  
Qun Xia

In order to explore the possibility of using repeatedly recycling waste concrete as aggregate to produce structural concrete, experimental research was carried out on the structural properties of three kinds of recycled fine aggregate (RFA) with two-regeneration cycles, two single and one mixed. The results showed that the quality of all RFAs meet the needs of Grade Ⅲ in GB/T25177-2010 and Level L in JISA 5023-2000. The degree of performance degradation is observed to enhance with increasing recycling cycle when taking the same preparation process of recycled aggregate.


2011 ◽  
Vol 368-373 ◽  
pp. 2185-2188
Author(s):  
Ping Hua Zhu ◽  
Xin Jie Wang ◽  
Jin Cai Feng

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.


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

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.


2021 ◽  
Vol 2 (1) ◽  
pp. 46-54
Author(s):  
Neti Rahmawati ◽  
Irwan Lakawa ◽  
Sulaiman Sulaiman

Concrete is one of the most widely used building materials today interms of physical construction. Concrete is made from a mixture offine, coarse aggregate, cement, and water with a certain ratio, aswell as materials that are usually added to the concrete mixtureduring or during mixing, to changing the properties of concrete tomake it more suitable in certain jobs and more economical, can alsobe added with certain other mixed materials as needed if deemednecessary. Seashells can be used to mix concrete. This study aims todetermine whether the addition of shells aggregate shells in aconcrete mixture can affect the mechanical properties of concrete.The specimens used are in the form of cubes with a size of 15cm x 15cm x 15 cm, consisting of additional concrete coarse and fineaggregate with shell substitution percentage of 0%, 15%, 20% with atotal sample of 45, with the planned concrete quality of K225. Theuse of sea shells in increasing the compressive strength of concrete isbetter used as fine aggregate than coarse aggregate. The use of seashells as a substitute for fine aggregates achieves maximum resultsat 20% composition.


2019 ◽  
Vol 6 (2) ◽  
pp. 145
Author(s):  
Budiman Budiman

Concrete waste from building construction can cause problems for the environment [1]. The use of fine aggregates from concrete waste can be a solution. The purpose of this study is to determine the value of aggregate characteristics and the value of concrete compressive strength from the utilization of concrete waste as substitution fine aggregate use the DOE (department of environment) method and referring to standards SNI. This study used 50% and 60% waste mortal substitution on sand. The results showed that the characteristics of fine aggregate and coarse aggregate met the characteristic requirements for fineness modulus sand of 2.65 (Zone 2) while the aggregate was roughly 6.44 (Zone 3). The value of compressive strength with 50% and 60% concrete waste substitution each obtained the value of characteristic compressive strength of 57.24 kg / cm² and 101.03 kg / cm². The value of using mortar waste as fine aggregate substitution gives a positive value to the quality of concrete. This is evidenced increase in the value of 14.89% in concrete waste substitution 60%.


2020 ◽  
Vol 15 (2) ◽  
pp. 57-69
Author(s):  
Daniel Hatungimana ◽  
Şemsi Yazıcı ◽  
Ali Mardani-Aghabaglou

ABSTRACT The possibility of the use of recycled aggregates from the construction industry in green concrete production is of increasing importance to reduce the negative environmental impact associated with construction and demolition wastes. The objective of this study is to investigate the effect of recycled concrete aggregate (RCA) quality on the properties of hardened concrete properties such as compressive strength, splitting tensile strength, density, water absorption capacity and porosity accessible to water. The RCA used in this study was obtained from the crushing of waste concrete with two different compressive strengths (LRCA obtained from the crushing of waste concrete having compressive strengths below 30 MPa and HRCA obtained from the crushing of waste concrete having compressive strengths above 30 MPa). The natural coarse limestone aggregate was 100% replaced with coarse LRCA and HRCA. As a result of the study, the use of 100% HRCA and %100 LRCA instead of limestone coarse aggregate in the concrete adversely affected its mechanical and physical properties. In addition, HRCA showed better performance in terms of compressive strength, tensile strength, water absorption and porosity compared to the use of LRCA. Furthermore, the percentage of adhered mortar on the surface of LRCA and HRCA was analyzed using a computerized micro tomography device, and it was found that the percentages of attached mortar and aggregates are 61% and 35.5% for LRCA, whilst the attached mortar and aggregate contents for HRCA are 45.9% and 53.7%, respectively.


2018 ◽  
Vol 3 (1) ◽  
pp. 55
Author(s):  
Suhendra Suhendra

Aggregate quality is very influential on the strength of the resulting concrete. Both coarse and fine aggregates have various characteristics identified from laboratory test results. This study aims to examine the use of various aggregates for a quality of concrete. The coarse aggregate and the fine aggregate used are obtained from the nearest location to the work to be performed. The quality of the concrete reviewed is K-125, K-175 and K-225. The coarse aggregates used are 1-2 size (in cm), 2-3 size (in cm) crushed aggregate and coral. The fine aggregates used for each of the coarse aggregates are also different. The results showed that the coral aggregate did not meet the gradations of concrete aggregate. While the fine aggregate does not meet the gradation of concrete aggregate for the three types used. The concrete compressive strength test results show the use of coarse aggregates of 2-3 size of crushed and coarse aggregate of corals giving the average compressive strength value required for all planned concrete strength. While concrete using coarse aggregates of rocks of size 1-2 only meet the specified compressive strength, but does not meet the required compressive strength.Key words: Aggregates, concrete, compressive strength


2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Idi Priyono ◽  
Meiske Widyarti, Erizal

An excessive extraction of natural resources for aggregate in concrete mix can caused an environmental degradation.  According to Indonesia ministry of industry in 2017, the use of cement is predicted will reach 84,96 million tons, that can affected the use of aggregate for concrete mix are quadruplet to 250 – 350 million tons. Opimally, the use of recycled material is green method that can reduce an excessive extraction of natural aggregates and keep an environmental sustain. The aim of this study is to obtain recycled aggregate concrete compressive strength and examine recycled aggregate concrete quality in days 3, 7, 28, 35, and 90 along with a proposal of the use of recycled aggregate concrete as a building construction material. This research used experimental method of SNI 03-2834-2002 the standard of normal concrete mix design for f’c 25 MPa then built five types of concrete mix of REC B, REC C, REC D, REC E, and REC F with every types of concrete has four sample are used for compressive strength test. The fine recycled paving block aggregate (RPA) were used partially to substituted a fine recycled brick aggregate (RBA) at 0%, 25%, 50%, 75%, and 100% by weigth. The result of this study showed the mixed concrete REC D with RCA 100%, RPA 50% and RBA 50% in 28 days is generate highest compressive strength than other recycle aggregates concrete mixes. Compressive strength at 28 days in a mix codes REC B, REC C, REC D, REC E and REC F are 18,12 MPa; 18,36 MPa; 19,35 MPa;16,69 MPa; and 16,39 MPa. The results show that it is feasible to replace a natural aggregate entirely by recycled aggregates. With compressive strength over 17 MPa at 28 days, mix codes REC B, REC C and REC D are recommended to use the recycled aggregate concrete for structure of residential buildings but mix codes REC E and REC F aren’t recommended and only allowed for non-structural concrete such as separate wall (SNI 8140:2016). Based on SNI 03-0691-1996 about solid brick concrete (paving block), recycle aggregate concrete with mix code of REC B, REC C, and REC D are able to use on paving block with B quality such as parking lot. While, recycled aggregate concrete with mix code of REC E and REC F are able to use on paving block with C and D quality which used for pedestrian, garden and other use. 


2005 ◽  
Vol 2 (2) ◽  
pp. 49
Author(s):  
Ahmad Ruslan Mohd Ridzuan ◽  
Azmi Ibrahim ◽  
Abdul Manaff Mohd Ismail

The effects of using crushed waste concrete as course aggregates upon compressive strength and carbonation were investigated. Waste concrete cubes, which had been tested for compressive strength in compliance with construction specification, were crushed and utilized as coarse recycled aggregates in new concrete. It is important to mention that, in order to simulate the real life conditions, waste concrete with very minimal information about its originality was used in its natural moisture condition. Tests on the aggregates showed that the recycled concrete aggregates have lower specific gravity and bulk density but have higher water absorption capacity than the natural aggregates. The resistance to mechanical actions such as impact and crushing for recycled concrete aggregates is also lower. Concrete mixes with design strength of 30 N/mm2, 35 N/mm2 and 40 N/mm2 were prepared using this recycled aggregates as coarse aggregates and tested. From the strength point of view the recycled aggregate concrete compared well with natural aggregate concrete. Therefore, it could be considered for various potential applications. With respect to resistance to carbonation the recycled aggregate concrete shows comparable performance.


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