INVESTIGATION OF STRESS - STRAIN BEHAVIOUR OF RECYCLED AGGREGATE CONCRETE UNDER CYCLIC LOADS

2015 ◽  
Vol 14 (7) ◽  
pp. 1543-1552 ◽  
Author(s):  
Antonella D'Alessandro ◽  
Marco Breccolotti ◽  
Francesca Roscini ◽  
Massimo Federico Bonfigli
2021 ◽  
Vol 1166 ◽  
pp. 81-94
Author(s):  
Ganesh D. Awchat

Demolish existing structures for better economic gains, functional and structural performance, and non-availability of land or disposal sites in nearby areas of all major cities worldwide turned as a significant reason for the crushing demolished concrete instead of using it as landfill. Research work aimed at arriving Recycled Concrete (RC) with the help of two materials, i.e. Steel Fibers (SF) and Styrene-Butadiene Rubber (SBR) latex, as additives to improve strength parameters of it. SF and SBR added in RC to examine & strengthen and termed as Steel Fiber Reinforced Polymer Modified Recycled Aggregate Concrete (SFRPMRAC). For this purpose, 198 cubes each of M20 (trial-1) and M25 (trial-2) cast separately to check compressive strength and its stress-strain behaviour for Natural Concrete (NC), RC & SFRPMRAC. The volume fractions of SF added 0.5%, 1% & 1.5% m3 of concrete and dosages of SBR latex varied from 2.5%, 5% and 7.5% by cement weight for preparation of cubes made of RC. From experimental results, SFRPMRAC with SF volume fraction of 1% m3 of concrete and 5% by cement weight provides an improvement in compressive strength by 8.62 % & 10.73 % for trial -1 and 11.51 % & 12.57 % for trial - 2 at 28 & 90 days when compared with NC. Compression stress-strain behaviour for SFRPMRAC with SF 1% m3 of concrete and 5% by weight of cement shows higher strain values at the peak stress. SFRPMRAC arrests the sudden drop of load due to co-matrix bond formation between SF and SBR in a linear direction compared to a similar NC & RC mix for both trials. It reflects significant improvement and approval of compressive strength for the desired purpose.


2021 ◽  
Vol 13 (10) ◽  
pp. 5741
Author(s):  
Muhammad Junaid Munir ◽  
Syed Minhaj Saleem Kazmi ◽  
Yu-Fei Wu ◽  
Xiaoshan Lin ◽  
Muhammad Riaz Ahmad

The addition of macro-polypropylene fibres improves the stress-strain performance of natural aggregate concrete (NAC). However, limited studies focus on the stress-strain performance of macro-polypropylene fibre-reinforced recycled aggregate concrete (RAC). Considering the variability of coarse recycled aggregates (CRA), more studies are needed to investigate the stress-strain performance of macro-polypropylene fibre-reinforced RAC. In this study, a new type of 48 mm long BarChip macro-polypropylene fibre with a continuously embossed surface texture is used to produce BarChip fibre-reinforced NAC (BFNAC) and RAC (BFRAC). The stress-strain performance of BFNAC and BFRAC is studied for varying dosages of BarChip fibres. Results show that the increase in energy dissipation capacity (i.e., area under the curve), peak stress, and peak strain of samples is observed with an increase in fibre dosage, indicating the positive effect of fibre addition on the stress-strain performance of concrete. The strength enhancement due to the addition of fibres is higher for BFRAC samples than BFNAC samples. The reduction in peak stress, ultimate strain, toughness and specific toughness of concrete samples due to the utilisation of CRA also reduces with the addition of fibres. Hence, the negative effect of CRA on the properties of concrete samples can be minimised by adding BarChip macro-polypropylene fibres. The applicability of the stress-strain model previously developed for macro-synthetic and steel fibre-reinforced NAC and RAC to BFNAC and BFRAC is also examined.


2014 ◽  
Vol 46 ◽  
pp. 65-72 ◽  
Author(s):  
Jodilson Amorim Carneiro ◽  
Paulo Roberto Lopes Lima ◽  
Mônica Batista Leite ◽  
Romildo Dias Toledo Filho

2013 ◽  
Vol 671-674 ◽  
pp. 1736-1740
Author(s):  
Xue Yong Zhao ◽  
Mei Ling Duan

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.


2021 ◽  
Vol 8 ◽  
Author(s):  
Yunchao Tang ◽  
Wanhui Feng ◽  
Zheng Chen ◽  
Yumei Nong ◽  
Minhui Yao ◽  
...  

The utilization of recycled aggregates made from construction wastes and recycled rubber made from waste tires is an effective method to realize the sustainable development. Thus, this study aims to determine the feasibility of using recycled aggregate concrete containing rubber, named rubberized recycled aggregate concrete (RRAC) as a new type of green-building material. The experimental carbon emissions test verified RRAC as a low-carbon material. In addition, the residual mechanical properties of RRAC were investigated under elevated temperatures. After exposure at 200, 400, and 600 C for 60 min, the stress−strain curve, compressive strength, energy absorption capacity, and spalling resistance of RRAC with recycled aggregate replacement ratios of 50 and 100%, rubber contents of 0, 5, 10, and 15% were explored with microstructural analysis. Moreover, empirical models were proposed to describe the effects of heated temperatures and rubber contents on the stress–strain relationship of RRAC. The results indicated that the rubber particles could reduce the spalling of specimens based on the vapor pressure theory. Therefore, this study provided scientific guidance for the design of structures made with RRAC for resisting high temperatures.


2019 ◽  
Vol 97 ◽  
pp. 341-356 ◽  
Author(s):  
Syed Minhaj Saleem Kazmi ◽  
Muhammad Junaid Munir ◽  
Yu-Fei Wu ◽  
Indubhushan Patnaikuni ◽  
Yingwu Zhou ◽  
...  

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