scholarly journals Virtual Revision on Compressive Srength of Conventional Concrete and Recycled Aggregate Concrete Consisting Treated Recycled Aggregate

2019 ◽  
Vol 8 (3) ◽  
pp. 3439-3443

Use of reused aggregate in concrete can be useful for the ecological protection and economical terms. The application of recycled has been started in many construction projects. Paper hear says the basic properties of recycled concrete aggregate. It similarly relates the properties with natural aggregate, similarly the properties of recycled aggregates concrete were also determined and explained here. For the concrete grades of M25 and M30, the recycled aggregate concrete is produced by changing the natural aggregate, by recycled aggregate in conventional concrete with 5%, 10% and 15% of weight of natural aggregates. Experimental studies were carried out on influence of recycled aggregate treatment and comparison of strength properties of conventional cement concrete and recycled aggregate concrete at the curing of 7days and 28 days. They are two types of treatments under the considerations for recycled aggregates are Abrasion of recycled aggregate and chemical immersion

Author(s):  
Suhail Mushtaq Khan

Recycled aggregates are those crushed cement concrete or asphalt pavement which comes out from the construction debris which is reused in construction. They are made from the reprocessing of materials which have been used in previous constructions. This paper discusses about the study of properties of recycled aggregates from the sources which has already been published. The results are that 100% replacement of natural aggregate by recycled concrete aggregate effect on chloride ions resistance, it plays negative effects on durability of recycled concrete aggregates, and addition of fiber in recycled aggregate concrete mixture gave more effective in the performance of concrete. On experimental study of recycled aggregate, compressive, flexural and split tensile strength of the recycled aggregate were found to be lower than that of the natural aggregate. Use of recycled aggregate in a new concrete production is still limited. Recommendation of introduction of recycled aggregates standard is required for the materials to be used successfully in future. Gaps in literature reviews are also included in this paper.


2019 ◽  
Vol 262 ◽  
pp. 06010
Author(s):  
Marek Węglorz ◽  
Andrzej Ajdukiewicz ◽  
Alina Kliszczewicz

Assessment of recycled aggregate concrete (RAC) properties by laboratory tests is still required due to lack of precise guidelines and with taking into account slightly different behaviour of such concretes in comparison with natural aggregate concretes (NAC). It is especially important when recycled concrete aggregates are used for the structural elements. In this paper, the following rules for the whole concrete recycling cycle were defined: (1) rules for examination of original concretes selected for recycling and (2) rules for aggregate preparation and their fractionize as well as design rules for recycled aggregate concrete mixtures (including required tests of recycled aggregates and concrete properties). Requirements towards recycled aggregate concrete formulated in this paper are based on the long term experience and research works on the RAC which were held by A. Ajdukiewicz and A. Kliszczewicz in the Department of Structural Engineering of the Silesian University of Technology, practically since 1995.


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. 


2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Ma Kang ◽  
Li Weibin

The study on preparation technology of recycled concrete with economical and technical feasibility has gained more serious attention in each country due to its involvement and effect on the environment protection and the sustainable development of human society. In this study, we conducted a control variable test to investigate and assess the influence of the aggregate size on the strength characteristics of concrete with different diameters of recycled aggregates. Concrete with recycled aggregates of 5∼15 mm (A), 15∼20 mm (B), 20∼30 mm (C), and their combinations were subjected to a series of unconfined pressure tests after curing for 28 days. Based on the results obtained from the tests, an effort was made to study the relationship between the mechanical characteristics of recycled aggregate concrete and aggregate particle size. Also, a regression model of recycled concrete was proposed to predict the elasticity modulus and to adjust the design of mixture proportion. It is believed that these experiment results would contribute to adjust the remediation mixture for recycling plants by considering the influence of recycled aggregate size.


2020 ◽  
Vol 23 (15) ◽  
pp. 3351-3369 ◽  
Author(s):  
Simret T Deresa ◽  
Jinjun Xu ◽  
Cristoforo Demartino ◽  
YeongAe Heo ◽  
Zhi Li ◽  
...  

This article presents a comprehensive and critical review of the structural performances of reinforced recycled aggregate concrete beams and columns based on experimental results reported in the literature. Extensive data sets collected from the literature are categorized to investigate the effects on the local and global structural behavior. First, the flexural and shear response of reinforced recycled aggregate concrete beams is discussed. The structural performances are reviewed focusing on the main geometric and material variables such as the recycled concrete aggregate replacement ratio, the longitudinal reinforcement ratio, the transverse reinforcement ratio, and the shear span-to-depth ratio. Then, the behavior of reinforced recycled aggregate concrete columns under concentric and eccentric compressive loads and the seismic performance under low cyclic loading are discussed. The similarities and the differences between reinforced recycled aggregate concrete and reinforced natural aggregate concrete beams and columns are highlighted. The need for further research is pointed out at the end of the article. The results reported in this review clearly indicate that reinforced recycled aggregate concrete beams and columns with various recycled concrete aggregate replacement ratios have comparable or slightly lower structural performances to the reinforced natural aggregate concrete ones indicating the feasibility of recycled concrete aggregate for structural applications.


Author(s):  
Khaoula Naouaoui ◽  
Azzeddine Bouyahyaoui ◽  
Toufik Cherradi

Recycled aggregate concrete is considered the next generation in the field of construction: it respects the environment, solves the problem of debris management and is economically profitable. In order to better adapt its use, technical studies, experimental studies and simulations are carried out in all research centers around the world in order to define its field of application. Our study falls within this framework. It is concerned with the study of the mechanical characteristics of recycled aggregate concrete essentially the compression test for various percentages of replacement. The purpose of this study is to confirm the results of studies by other researchers and to find techniques that will maximize the replacement of natural aggregates with recycled aggregates. The concrete chosen for these tests is an old building in the region of Rabat, Morocco which has been built more than 40 years and demolished in the year of 2017. The tests carried out showed a decrease in the compressive resistance noted when the replacement rates exceed 50% rate. The first improvement methods were put in place and being tested: the partial replacement of cement with pozzolan (20% rate) known by his improving of the compressive strength for ordinary concrete, the partial replacement of the large proportion [12.5-31.5] only in recycled concrete and work with natural gravels. Other improvements will be proposed as the studies progress.


2009 ◽  
Vol 1 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Yong P.C. ◽  
Teo D.C.L

In this rapid industrialised world, recycling construction material plays an important role to preserve the natural resources. In this research, recycled concrete aggregates (RCA) from site-tested concrete specimens were used. These consist of 28-days concrete cubes after compression test obtained from a local construction site. These concrete cubes are crushed to suitable size and reused as recycled coarse aggregate. The amount of recycled concrete aggregate used in this research is approximately 200 kg. Many researchers state that recycled aggregates are only suitable for non-structural concrete application. This research, however, shows that the recycled aggregates that are obtained from site-tested concrete specimen make good quality concrete. The compressive strength of recycled aggregate concrete (RAC) is found to be higher than the compressive strength of normal concrete. Recycled aggregate concrete is in close proximity to normal concrete in terms of split tensile strength, flexural strength and wet density. The slump of recycled aggregate concrete is low and that can be improved by using saturated surface dry (SSD) coarse aggregate.


2009 ◽  
Vol 620-622 ◽  
pp. 255-258 ◽  
Author(s):  
Cheol Woo Park

As the amount of waste concrete has been increased and recycling technique advances, this study investigates the applicability of recycled concrete aggregate for concrete structures. In addition fly ash, the industrial by-product, was considered in the concrete mix. Experimental program performed compressive strength and chloride penetration resistance tests with various replacement levels of fine recycled concrete aggregate and fly ash. In most case, the design strength, 40MPa, was obtained. It was known that the replacement of the fine aggregate with fine RCA may have greater influence on the strength development rather than the addition of fly ash. It is recommended that when complete coarse aggregate is replaced with RCA the fine RCA replacement should be less than 60%. The recycled aggregate concrete can achieve sufficient resistance to the chloride ion penetration and the resistance can be more effectively controlled by adding fly ash. It I finally conclude that the recycled concrete aggregate can be successfully used in the construction field and the recycling rate of waste concrete and flay ash should be increased without causing significant engineering problems.


2012 ◽  
Vol 174-177 ◽  
pp. 1277-1280 ◽  
Author(s):  
Hai Yong Cai ◽  
Min Zhang ◽  
Ling Bo Dang

Compressive strengths of recycled aggregate concrete(RAC) with different recycled aggregates(RA) replacement ratios at 7d, 28d, 60d ages are investigated respectively. Failure process and failure mode of RAC are analyzed, influences on compressive strength with same mix ratio and different RA replacement ratios are analyzed, and the reason is investigated in this paper. The experimental results indicate that compressive strength of recycled concrete at 28d age can reach the standard generally, it is feasible to mix concrete with recycled aggregates, compressive strength with 50% replacement ratio is relatively high.


2019 ◽  
Vol 22 (8) ◽  
pp. 1938-1951 ◽  
Author(s):  
George Wardeh ◽  
Elhem Ghorbel

This article presents an experimental program on the shear behavior of beams without transversal reinforcement manufactured with natural aggregate concrete and 100% recycled aggregate concrete. The beams were tested under four-point bending for a shear span-to-depth ratio ( a/ d) equal to 1.5 and 3.0. The mechanical properties of two mixes were characterized in terms of compressive strength, splitting tensile strength, and elastic modulus. Three-point bending tests were performed on plain pre-notched samples in order to determine the fracture properties by an inverse analysis of experimental force–crack mouth opening displacement curves using the analytical nonlinear hinge model and a power law strain-softening relationship. The strain-softening law is described by two parameters being, respectively, the power n and the critical crack opening displacement wc. The experimental results show that, for the same class of compressive strength, tensile strength, fracture energy, and the shear strength of recycled aggregate concrete are lower than natural aggregate concrete. The decrease in the fracture energy and the shear strength is consistent with the decrease in the splitting tensile strength of the recycled aggregate concrete mixes compared to the natural aggregate concrete. Critical shear crack theory was adopted to model the shear behavior of beams tested with a/ d = 3.0. For an accurate evaluation of the deformation capacity of tested beams, the nonlinear hinge model for recycled concrete members was extended to recycled concrete sections. For deep beams ( a/ d = 1.5), the strut-and-tie model was used. Finally, comparisons of prediction models to a wide range of experimental data are presented.


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