MECHANICAL PROPERTIES OF REINFORCED CONCRETE BEAM WITH RECYCLED COARSE AGGREGATES

2017 ◽  
Vol 3 (2) ◽  
pp. 105
Author(s):  
P. J. Jaua Junior ◽  
Clotilda Petrus ◽  
J.D. Nyuin

The significant increment of waste concrete in recent years that is happening worldwide has a tremendous consequence to the environment. Recycling concrete wastes will reduce the amount of waste as well as save natural resources, thus help promote green and sustainable development. This study presents an experimental investigation dealing with the development of green concrete using recycled concrete waste (RCWA) as coarse aggregate replacement materials. The mechanical properties of reinforced concrete (RC) beams in terms of its compressive and flexural strengths were determined. The main parameter considered is the percentage of RCWA in the concrete design of RC beams that ranges from 0% to 50%.  From the test results, it was observed that the flexural strength and the compression strength decreased as the percentage of recycled concrete waste aggregate used increased. Generally, the flexural strength of RC beam with RCWA can be 5% to 12.4% lower than that of conventional concrete made with natural course aggregate.

2016 ◽  
Vol 2 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Hasan Jalilifar ◽  
Fatholla Sajedi ◽  
Sadegh Kazemi

The flexural strength of conventional concrete material is known to be enhanced by incorporating a moderate volume-fraction of randomly distributed fibers. However, there is limited information on describing the influence of fiber volume-fraction on the compressive and flexural strength of recycled coarse aggregate concrete (RCA-C) material. This paper reports on experimental test results of the RCA-C material replaced with 0, 30, 50 and 100% recycled aggregate and 0, 0.5, 1 and 1.5% steel fiber volume fraction. Three-point flexural tests of notched prism specimens were completed. The mechanical properties in compression were characterized using cube specimens. Significant improvement in compressive and flexural strength of RCA-C was found as fiber content increased from 0 to 1.5%. The experimental test results of RCA-C were further evaluated to investigate the influence of fiber content on flexural toughness. According to test results, the addition of steel fibers to RCA-C material appreciably increased the flexural toughness.


Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1137 ◽  
Author(s):  
Jongho Park ◽  
Sun-Kyu Park ◽  
Sungnam Hong

In this study, nine specimens were experimentally tested to analyze the strengthening efficiency of textile-reinforced mortar (TRM) and the difference in flexural behavior between prestressed and non-prestressed TRM-strengthened reinforced concrete beam. The test results show that TRM strengthening improves the flexural strength of TRM-strengthened reinforced concrete beams with alkali-resistant-(AR-) glass textile as well as that with carbon textile. However, in the case of textile prestressing, the strengthening efficiency for flexural strength of the AR-glass textile was higher than that of the carbon textile. The flexural stiffness of AR-glass textiles increased when prestressing was introduced and the use of carbon textiles can be advantageous to reduce the decreasing ratio of flexural stiffness as the load increased. In the failure mode, textile prestressing prevents the damage of textiles effectively owing to the crack and induces the debonding of the TRM.


2011 ◽  
Vol 374-377 ◽  
pp. 1887-1890 ◽  
Author(s):  
Jing Li ◽  
Xian Feng Qu ◽  
Hai Yang Chen ◽  
Juan Li ◽  
Lin Jiang

In order to study the mechanical performance of self-compacting reinforced concrete beam with recycled coarse aggregates, recycled concrete and recycled gravel were taken as coarse aggregates with the particle size from 50 to150mm, two groups of specimen of self-compacting reinforced concrete beams with recycled coarse aggregates were made. After seven days, their bending strength were tested using method of one-third point loaded of simple beam on the testing machine. The results showed that the recycled coarse aggregates are bonded closely with the self-compacting concrete, its bond performance is good; Compared to ordinary reinforced concrete beam, it shows a smaller stiffness and a bigger mid-span deflection. In addition, the different combination of recycled concrete could reduce the self-compacting reinforced concrete’s stiffness with recycled coarse aggregate and increase its deflection.


2019 ◽  
Vol 9 (1) ◽  
pp. 3826-3831
Author(s):  
M. Oad ◽  
A. H. Buller ◽  
B. A. Memon ◽  
N. A. Memon ◽  
Z. A. Tunio ◽  
...  

This research paper presents an experimental evaluation of the effect of water-cement ratio on the flexural strength of reinforced concrete beams made with 50% replacement of coarse aggregates with recycled concrete aggregates (RCA). 72 reinforced concrete beams were cast using 0.54, 0.6, 0.65 and 0.70 water-cement ratio. In each ratio, 12 beams were cast using RCA and 3 beams were cast using all-natural coarse aggregates (NCA). Beams were cured for 7 and 28 days. After curing, all beams were tested with central point load in a universal load testing machine. From the obtained results, it is observed that the maximum reduction in flexural strength of RCA beams is about 28% when compared to the 0.54 w/c ratio beams of the same group and 31.75% in comparison to NCA beams cast with same w/c ratio. The maximum deflection and average strain in beams remained within limits. The observed cracking pattern shows shear failure of all beams.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Guifeng Zhao ◽  
Jiankun Xu ◽  
Yaoliang Li ◽  
Meng Zhang

The static load carrying capacity of a noncorroded reinforced concrete (RC) simply supported beam is numerically simulated by ABAQUS software, and the reliability of the finite element model is verified by comparing with the test results. Based on the above model, the macroscopic mechanical properties of the beam under different degrees of corrosion are calculated. In the calculation, the degradation of the bond-slip performance and mechanical properties of corroded rebars and the coupling effect on the bearing capacity and ductility degradation of the beams are considered. The results show that, under conditions of slight corrosion, the degradation of bond-slip performance between the rebar and concrete has no significant influence on the bearing capacity of the beam, while the degradation of the corroded rebar had a significant effect. Under moderate and severe corrosion conditions, the bearing capacity and ductility degradation caused by bond-slip are dominant in the mechanical property degradation of the beam. Overall, the macroscopic mechanical properties of the corroded beam are influenced by the coupling effect of bond-slip degradation and the mechanical property degradation of the rebar. With the increase in the corrosion rate, the bearing capacity and ductility of the beam are decreased, and its brittleness is increased.


2011 ◽  
Vol 243-249 ◽  
pp. 1461-1465
Author(s):  
Chuan Min Zhang ◽  
Chao He Chen ◽  
Ye Fan Chen

The paper makes an analysis of the reinforced concrete beams with exterior FRP Shell in Finite Element, and compares it with the test results. The results show that, by means of this model, mechanical properties of reinforced concrete beams with exterior FRP shell can be predicted better. However, the larger the load, the larger deviation between calculated values and test values. Hence, if more accurate calculation is required, issues of contact interface between the reinforced concrete beams and the FRP shell should be taken into consideration.


2013 ◽  
Vol 438-439 ◽  
pp. 749-755 ◽  
Author(s):  
Tong Hao ◽  
Dong Li

By the experimental studying on the basic mechanical properties of recycled concrete hollow block masonry, the compressive and shear behavior of recycled aggregate concrete hollow block masonry under different mortar strength were analyzed. Research indicated that the compressive and shear behavior of recycled aggregate concrete hollow block masonry was similar to that of ordinary concrete hollow block masonry. The normal formula was recommended to calculate the compressive strength of the masonry. The shear strength of the masonry was affected by the mortar strength. The shear strength calculation formula of recycled concrete hollow block masonry was proposed according to the formula of masonry design code. The calculating results were in good agreement with the test results.


2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Eethar Thanon Dawood ◽  
Mahyuddin Ramli

This study was conducted to determine some physical and mechanical properties of high-strength flowable mortar reinforced with different percentages of palm fiber (0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, and 1.6% as volumetric fractions). The density, compressive strength, flexural strength, and toughness index were tested to determine the mechanical properties of this mortar. Test results illustrate that the inclusion of this fiber reduces the density of mortar. The use of 0.6% of palm fiber increases the compressive strength and flexural strength by about 15.1%, and 16%, respectively; besides, the toughness index (I5) of the high-strength flowable mortar has been significantly enhanced by the use of 1% and more of palm fiber.


2013 ◽  
Vol 592-593 ◽  
pp. 647-650 ◽  
Author(s):  
Małgorzata Lenart

Cement – polymer composites are nowadays widely used in repair systems not only in case of concrete or reinforced concrete constructions but also in masonry. Polymers addition for example already at 5% m.c. modifies the structure of the cement – polymer composite in a way that many of the mechanical properties such as flexural strength, tensile strength or adhesion to substrates are improved. The paper presents the results of tests such as flexural, compressive or adhesion strength to ceramic substrate of hardened cement mortars with different composition, as well as selected cement mortars modified by two polymers: polyvinyl alcohol and styrene – butadiene polymer dosed at 5 % m.c. Four types of cement mortars modified by lime (component used in historical constructions as well as in contemporary masonry mortars) are also examined for comparison.


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