Flexural Behavior of Basalt Fiber Reinforced Concrete Beams with Recycled Concrete Coarse Aggregates

Abstract

The State of Qatar has experienced tremendous economic development in the last decades. As a result, massive quantities of building materials have been used to accommodate the great pace in construction. However, Qatar suffers from the shortage of natural resources needed for concrete production. Therefore, it is essential to investigate the feasibility of reusing construction and demolition waste as aggregates to maintain the concrete construction industry. Recycled concrete aggregate (RCA) has been produced in Qatar since 2009 as a result of the extensive construction and demolition activities. The purpose of this study is to study the effect of using RCA combined with a newly developed basalt macro fibers (BMF) on the flexural behavior and ultimate capacity of beams with different replacement ratios of RCA experimentally and analytically. A total of 16 concrete beam specimens were flexural tested until failure. The parameters investigated included the RCA replacement ratio (0%, 25%, 50%, and 100%) and the BMF volume fraction (0%, 0.5%, 1% and 1.5%). The deflection, concrete compressive strain and steel tensile strain at mid-span of the tested beams were measured and recorded. The testing results of the specimens were compared to the control beam specimen with natural aggregate (Gabbro), without BMF. In addition, a critical comparison study was carried out between the experimental findings of this research and the analytical formulations based on the existing code-based analytical models. The test results showed an improvement in the flexural capacity of the beam specimens with the addition of BMF, while there are no remarkable effects of RCA on flexural strength of the tested beams. Test results clearly showed that both RCA and BMF in Qatar can be used as sustainable and eco-friendly alternative materials in concrete structures.