الفهرس 
Title : Flexural Behavior Of Recycled Aggregate Reinforced Concrete Beams
SummaryOnly 14 pages are availabe for public view
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Abstract
The process of recycling concrete has become an inevitable necessity to confront the increase in construction and demolition waste, as well as the high prices of raw materials and transportation, and the fact that the sources of these materials are non-renewable sources contributed to accelerating the pace of reliance on the waste recycling process. The rapid increase in construction and demolition waste drew the attention of governments and investors to make the best use of it. Therefore, researchers began conducting the necessary studies to discover the behavior of recycled concrete and its impact on structural behavior of buildings.
This research investigates the flexural behavior of concrete beams incorporating recycled coarse aggregate (RCA) utilizing detailed experimental data from eight beams: two control beams with natural coarse aggregate (NCA) and six beams with varied RCA contents. The parameters considered in this study include the RCA content (50% and 100%) and the longitudinal reinforcement ratio: lower (0.56% and 1%) and upper (0.14, 0.25, and 0.7). To achieve the research’s purpose, the physical and mechanical properties of recycled coarse aggregates (RCAs) were evaluated and compared to natural coarse aggregates (NCAs), by conducting several laboratory tests. Also, in order to determine the mechanical properties of plain concrete, six cubes and six cylinders were taken from each recycled coarse aggregate mix, then cured and tested after 7 and 28 days, then compared the results to its counterpart made from natural coarse aggregate mixes. In addition to evaluating the flexural capacity, maximum short-term deflection, crack patterns, and mode of failure of the RCA beams by studying their structural behavior under gradually increased two equal concentrated loads and comparing them with those the NCA beams.
The results showed that the crack pattern of the RCA beams was similar to that of the NCA beams. Although the RCA beams had a lower cracking load than the NCA beams, there was no significant difference in the yielding load of the RCA and NCA beams. Using high ratio of compression steel with RCA beams leads to cracking load identical to the NCA beams. In general, as the RCA content increased, the ductility index of the beams decreased, but the ductility index was not considerably impacted by the RCA content with a high lower reinforcement ratio of 1%. The RCA content had a minor effect on flexural strength. The stiffness of the beam increased as well with increasing longitudinal reinforcement and RCA replacement ratios. The 50% RCA beams perform better than the 100% RCA beams in terms of toughness. When experimental flexural results were compared to those estimated using the ECCS 203-2020 and ACI 318-19 provisions, it was observed that the existing codes conservatively predict the flexural strength of the RCA beams.