الفهرس 
Title : Shear behaviour of repaired recycled aggregate concrete beams using cfrp sheets
SummaryOnly 14 pages are availabe for public view
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Abstract
The increase in construction and demolition (C and D) waste in recent decades has become a burden on most countries as a result of environmental pollution and the need for landfills to dispose these waste in addition to energy consumption, so recycling of these waste has become a necessity, not an option to preserve the environment by reducing the pollution and to save natural raw materials. RCA represents a large proportion of C and D waste and can be used in new concrete mixes with partial replacement or full replacement of natural coarse aggregate (NCA).
An experimental study conducted to investigate the effect of using RCA on the mechanical behavior of concrete. Moreover, this research aims to assess the effect of repair using CFRP strips on the shear strength of preloaded beams made with RCA with different ratios. Thus, four point bending test has been performed on eight reinforced concrete beams divided into two groups, each group consists of four beams with RCA replacement ratios ranging from 0% to 100% in order to evaluate the structural performance of the tested beams, in terms of crack pattern, shear strength, load-deflection relation, energy absorption “toughness” and stiffness of the beams. Four concrete mixes used with 0%, 30%, 70% and 100% RCA replacement ratios to construct the eight tested beams.
The results of un-repaired beams showed the same crack pattern, crack propagation and mode of failure investigated for all beams regardless the RCA replacement ratio. However, the higher the percentage of RCA in the concrete mix, the lower the shear strength, although the average compressive strength of tested cubes of the three mixes with 30%, 70%, 100% RCA ratios were little higher than the control mix with natural coarse aggregate.
For the repaired beams, CFRP strengthening technique increased the shear strength, stiffness, and toughness of all repaired beams regardless the RCA ratio in the concrete mix.
The experimental results compared with two design codes to check the applicability of using their equations in estimating the design strength of the tested beams with different replacement ratios of RCA. Furthermore, the experimental results compared with the proposed equations suggested in previous research that can evaluate the nominal shear strength of beams containing different rations of RCA.