SHEAR BEHAVIOR OF SUSTAINABLE REINFORCED HIGH- STRENGTH CONCRETE BEAMS WITHOUT STIRRUPS

Abstract

This research raises the importance of using the recycled aggregates in constructions as an alternative solution to the conventional natural aggregates. Six specimens were cast and tested, using two types of natural and recycled aggregates. Two types of additive ratios of recycled aggregates including 50% and 100%, were considered. During the cast, all beams had 1300 mm length and rectangular cross-section with breadth and height of 100 and 150 mm, respectively. Steel fibers were added by 2% to 5 beams, while the last one without fibers. The test results provided considerable enhancement in shear capacity along with the considerable delay in the cracking load when steel fibers were added. The increasing in ultimate load regarding the beams which contain steel fibers by 2% is about 36% compared to the beams with a content of 0% for the same type of aggregate. It was noticed that the shear resistance of specimens containing 50% and 100% of untreated RCA decreased by 10.5% and 27.5%, respectively compared to tests containing natural aggregates. In contrast, significant improvement in the shear resistance was recorded when using treated aggregates, whereas treated aggregate gave close results to normal aggregate. The discrepancy in the ultimate load for mixtures having 50% and 100% of treated RCA was only 1.9% and 9%, respectively to the values gained from NSC.