scholarly journals Analysis of High Strength Concrete processed from Recycled Concrete Aggregates

2021 ◽  
Vol 9 (12) ◽  
pp. 1757-1763
Author(s):  
Shanu Sharma
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Strain Curve ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Hardened Concrete ◽  
Stress Strain Curve ◽  
Stress Strain

Abstract: As everyone is aware of the fact that Natural Coarse Aggregate (NCA) is the main constituent of traditional concrete mixes. Whenever an existing concrete structure is demolished, it produces smashed concrete waste in the large amount. Concrete waste give rise to negative effects on the environment. To evade the environmental pollution and mark effective reuse of the concrete waste as Recycled Aggregates in the place of NCA. This operative initiative provides an opportunity to reduce air pollution and soil exploitation to some extent. Such concrete is sustainable in nature and also eco-friendly to the environment. Also, such waste material will lower the usage of naturally occurring stone to produce NCA and thus various natural energy resources will be safeguarded. This study covers the suitability norms for a material to be used for Recycled Aggregate. In this study the natural aggregate is replaced with recycled aggregate in the different percentages (0%, 25%, 50%). When percentage of recycled aggregate mixed in the fixed proportion as percentage replacement to natural aggregates, it imparts improvement in the property of fresh as well as hardened concrete like, compressive strength & split tensile strength. Laboratory results of this research indicates that the value of compressive strength, tensile strength stress-strain curve & NDT of these mixes drives on decreasing, but at the 25% replacement level, it achieves target mean strength. Hence, for the fundamental concrete mix Natural Coarse Aggregate can be efficiently replaced by the Recycled Aggregate to the range of 25%. Keywords: Concrete, Recycled aggregate, Natural Coarse Aggregate (NCA), Compressive Strength, Tensile strength, , NDT, Stress-Strain Curve

scholarly journals Stress-strain curve of concretes with recycled concrete aggregates: analysis of the NBR 8522 methodology

2017 ◽  
Vol 10 (3) ◽  
pp. 547-567 ◽  
Author(s):  
D. A. GUJEL ◽  
C. S. KAZMIERCZAK ◽  
J. R. MASUERO
Keyword(s):  
Test Procedure ◽  
Strain Curve ◽  
Recycled Concrete ◽  
Load Test ◽  
Recycled Aggregates ◽  
Elastic Behavior ◽  
It Use ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Brazilian Standard

ABSTRACT This work analyses the methodology "A" (item A.4) employed by the Brazilian Standard ABNT 8522 (ABNT, 2008) for determining the stress-strain behavior of cylindrical specimens of concrete, presenting considerations about possible enhancements aiming it use for concretes with recycled aggregates with automatic test equipment. The methodology specified by the Brazilian Standard presents methodological issues that brings distortions in obtaining the stress-strain curve, as the use of a very limited number of sampling points and by inducing micro cracks and fluency in the elastic behavior of the material due to the use of steady stress levels in the test. The use of a base stress of 0.5 MPa is too low for modern high load test machines designed do high strength concrete test. The work presents a discussion over these subjects, and a proposal of a modified test procedure to avoid such situations.

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.

Experimental Research on Mechanical Properties of Recycled Aggregate Concrete under Uniaxial Loading

2013 ◽  
Vol 671-674 ◽  
pp. 1736-1740
Author(s):  
Xue Yong Zhao ◽  
Mei Ling Duan
Keyword(s):  
Elastic Modulus ◽  
Coarse Aggregate ◽  
Strain Curve ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Peak Strain ◽  
Stress Strain ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate

The complete stress-strain curves of recycled aggregate concrete with different recycled coarse aggregate replacement percentages were tested and investigated. An analysis was made of the influence of varying recycled coarse aggregate contents on the complete stress-strain curve, peak stress, peak strain and elastic modulus etc. The elastic modulus of RC is lower than natural concrete (NC), and with the recycled coarse aggregate contents increase, it reduces. While with the increase of water-cement ratio (W/C), recycled concrete compressive strength and elastic modulus improve significantly. In addition, put forward a new equation on the relationship between Ec and fcu of the RC.

scholarly journals Performance of Recycled Aggregate Concrete for M25 Grade Concrete

2019 ◽  
Vol 9 (2) ◽  
pp. 4694-4700
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Aggregate Concrete ◽  
Inorganic Particles ◽  
Natural Aggregates

Recycled aggregates (RCA) are the aggregates which are made up of crushed, inorganic particles that are obtained from the construction demolition debris. Now a day’s protection of environment is the ultimate challenge to the society. So the usage of RCA’s is the best alternative for the aggregates which are obtained naturally in the construction activity. The scope of using these recycled concrete aggregates is increasing day by day. It reduces the cost effectively as we are using waste concrete as recycled aggregates. The main focus of this paper is to use find the strength qualities of recycled aggregates so as to use it as an alternative for the natural aggregates in high strength concrete for various construction activities. Comparison of workability, compressive strength, tensile strength, elastic modulus and flexural strength of recycled aggregate concrete is made with natural aggregate concrete. Here M25 grade concrete is taken and the natural aggregates were replaced with recycled aggregates in various percentages of 0%, 25%, 50%, 75% and 100%. The mix design for these replacement ratios are done by using code of IS 10262-2009. In order to determine the properties which were mentioned above a total of 60 cubes, 10 beams and 40 cylinders were casted. The compressive strength and tensile strength of RCA concrete have been determined for 7 days and 28 days where as the modulus of elasticity and the flexural strength of RCA concrete are determined after curing for the period of 28 days. The tests done on RCA concrete are compared with concrete which is obtained by natural aggregates As per IS codification the parameters which were determined are reducing moderately as the amount of aggregates which are recycled is being raised

scholarly journals The influence of recycled concrete aggregate on the properties of concrete

2018 ◽  
Vol 162 ◽  
pp. 02020 ◽  
Author(s):  
Nisreen Mohammed ◽  
Kaiss Sarsam ◽  
Mazin Hussien
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Modulus Of Rupture ◽  
Concrete Aggregate ◽  
Hardened Concrete ◽  
Recycled Coarse Aggregate ◽  
Natural Aggregates

Use of Recycled Coarse Aggregate (RCA) in concrete can be described in terms of environmental protection and economy. This paper deals with the mechanical properties of concrete compressive strength, splitting tensile strength, modulus of elasticity, and modulus of rupture. Three kinds of concrete mixtures were tested, concrete made with Natural Coarse Aggregate (NCA) as a control concrete and two types of concrete made with recycled coarse aggregate (50% and 100% replacement level of coarse recycled aggregate). These kinds of concrete were made with different targets of compressive strength of concrete f ’c (35MPa) and (70 MPa). Fifty specimens were tested of the fresh and hardened properties of concrete. The waste concrete from laboratory test cubes was crushed to produce the Recycled Coarse Aggregate used in recycled concrete. A comparative between the experimental results of the properties for fresh and hardened concrete is presented in the paper. Recycled aggregate concrete (RCA) had a satisfactory performance despite the replacement ratios. It was found using the size of Recycled Coarse Aggregate (RCA) of (5-14) mm has quite similar in performance with the same size of Natural Coarse Aggregate (NCA), it is necessary to use high quality of recycled concrete (with low levels of impurities). Recycled aggregate as an alternative to natural aggregates -seems quite successful.

Experimental Study on Stress-Strain Curve of Recycled Coarse Aggregate Concrete under Uniaxial Compression

2013 ◽  
Vol 357-360 ◽  
pp. 1415-1419 ◽  
Author(s):  
Zhi Heng Deng ◽  
Li Chen ◽  
Jian Qian ◽  
Chao Lou Meng
Keyword(s):  
Coarse Aggregate ◽  
Strain Curve ◽  
Recycled Concrete ◽  
Peak Strain ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Recycled Coarse Aggregate ◽  
Rational Expression ◽  
The Difference ◽  
Two Stages

In order to study the mechanical properties of recycled concrete with the same strength, three kinds of recycled concrete have been made which their intensities reached C25, C30, C35 at the recycled coarse aggregate replacement ratios (0%, 50%, 100%), and severally completed the stress-strain curve test on the same strength of recycled concrete, separately analyzed the variance about failure pattern and peak strain, elastic modulus that all belonged to recycled concrete under the condition of the same strength. Studies have shown that the overall shape of recycled concretes stress-strain curves is similar to normal concretes under the same strength, and the difference is small, modulus of elasticity decreases with the increase of recycled coarse aggregate replacement ratio, while the peak strain basicly remains unchanged. Their curves can be used two stages respectively and also be represented by three fitting polynomial and rational expression, their descent stages steepened gradually with the increase of recycled coarse aggregate replacement rate.

scholarly journals Evaluasi Blok Tegangan Tekan Ekuivalen Balok Beton Bertulang Agregat Limbah Batu Onyx Tulungagung

2021 ◽  
Vol 15 (1) ◽  
pp. 45-50
Author(s):  
Bobby Asukmajaya R. ◽  
◽  
Edhi Wahjuni S. ◽  
Wisnumurti Wisnumurti ◽  
◽  
...  
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Coarse Aggregate ◽  
Strain Curve ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Normal Concrete ◽  
Aggregate Concrete ◽  
Average Compressive Strength ◽  
Stress Block

Normal aggregate replacement to the onyx waste aggregate will certainly make the compressive strength and modulus of elasticity different, so it will affect the value of the compressive stress block equivalent (β1) as a result of the extent of the changing stress strain curve. In this study, trying to compare between the experimental β1 value of onyx concrete, while analytically the β1 value for normal concrete was obtained in accordance with SNI 2847 - 2019. To get the experimental β1 value from onyx concrete, it is made by looking for the compressive strength, elastic modulus and ꜫ0, for later the stress strain curve of the concrete is made to find the experimental β1 value of the onyx concrete. The results were obtained if the average β1 value of 18 specimens of onyx coarse aggregate concrete with an average compressive strength of 32.92 MPa was 0.868 while the analytical β1 value based on SNI 2847-2019 was 0.839, This shows that the B1 value for concrete with other aggregates is different, so it needs to be checked experimentally.

EFFECT OF RECYCLED CONCRETE AGGREGATE QUALITY ON PROPERTIES OF CONCRETE

2020 ◽  
Vol 15 (2) ◽  
pp. 57-69
Author(s):  
Daniel Hatungimana ◽  
Şemsi Yazıcı ◽  
Ali Mardani-Aghabaglou
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Water Absorption ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Concrete Aggregate ◽  
Hardened Concrete ◽  
Recycled Concrete Aggregate ◽  
Waste Concrete ◽  
Concrete Production

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.

Influence of Pro-Coating Coarse Aggregate on Engineering Properties of Recycled Concrete

2016 ◽  
Vol 858 ◽  
pp. 184-189
Author(s):  
Yi Han Fang ◽  
Ching Hao Chu ◽  
Wei Ting Lin ◽  
An Cheng ◽  
Wei Dong Liu
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Group Performance ◽  
Performance Testing ◽  
Ultrasound Velocity ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Engineering Properties ◽  
Recycled Aggregates ◽  
Lime Water

This study is aimed to investigate the effects of four kinds of pro-coating coarse aggregate included air-dried condition, 50 degrees Celsius curing for 24 hours, saturated lime water curing for 28 days and original recycled aggregate for a comparison group. Performance testing included slump, compressive strength, ultrasonic velocity, absorption and resistivity tests and were evaluated the fresh, mechanical and durability properties. Test results indicated that the specimens containing four kinds of recycled aggregates performed batter workability due to the smooth surface pro-coated with slag. The specimens containing pro-coating aggregate with 50 degrees Celsius curing had lower absorption, higher compressive strength, ultrasound velocity and resistivity than others due to the better denseness and compactness. At the age of 28 days, the recycled aggregates specimens with 50 degrees curing had 22 % higher compressive strength and 40 % lower absorption than the original recycled aggregate specimens. For engineering requirements, pro-coating technology should be applied to improve the engineered properties of concrete and promote the natural resources recycling technology.

Effects of Old Aggregate on Concrete Strength

2014 ◽  
Vol 1008-1009 ◽  
pp. 1352-1356
Author(s):  
Hui Lv ◽  
Chun Tao Wang
Keyword(s):  
Coarse Aggregate ◽  
Concrete Strength ◽  
Strain Curve ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Stress Strain ◽  
Ordinary Concrete ◽  
Recycled Coarse Aggregate ◽  
Basic Properties

The basic characteristics of recycled coarse aggregate are completely tested. Crushed the waste concrete through artificial crushing, configured recycled concrete by reference to the mix proportion of ordinary concrete . Through experiments, recycled concrete and ordinary concrete basic properties were tested, the performance of recycled concrete with different coarse aggregate were compared, calculated the strength and amount of mold of recycled concrete; results showed that the basic properties of recycled coarse aggregate and natural aggregate existed certain differences. compared to the pebble-based recycled aggregate concrete strength can reach ordinary concrete strength, and when the new coarse aggregate and recycled coarse aggregate were the half, the strength of concrete was not high, the stress - strain curve and the ordinary concrete stress - strain curves were similar, destructive phenomenons of test cubes were close with ordinary concrete .

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