NEW MODEL OF ECO-FRIENDLY HYBRID DEEP BEAMS WITH WASTES OF CRUSHED CONCRETE

Abstract

This paper presents a new model of hybrid sustainable deep beams that include crushed coarse aggregates (RCA) in place of natural aggregates. RCA was in three replacement ratios: 0%, 50%, and 100%. Six specimens of deep beams have been tested experimentally under static loads and were divided into two groups: the first group contains three specimens made with conventional hybrid deep beam models with a top layer of normal strength concrete including steel fibers (SFC) and a bottom layer of RCA with the three replacement ratios. In addition, the second group contains three specimens made with the proposed arched hybrid model SFRC within the arch region and RCA in other regions of the beam. Results revealed that when adopting the proposed model rather than the conventional hybrid model, the capacity improved by 13.5%, 19.7%, and 19.1% for the three replacement ratios, respectively. While the flexural toughness improved by 25.2%, 51.1%, and 62.1%, respectively. Moreover, results showed that for the conventional model, the mode of failure changed from flexure to diagonal with increasing RCA content. Whereas for the proposed model, the mode was kept to a flexural trend regardless of the RCA content in the bottom layer. The suggested arrangement of hybridization may be utilized to produce sustainable precast deep beams that minimize the impact of the waste of construction materials on the environment.