Mechanical behavior and environmental assessment of steel-bars truss slab using steel fiber-reinforced recycled concrete

Abstract

Steel-bar truss slab (SBTS) is a new type of floor system with a high construction speed and environmental benefits. In this study, four-point bending tests were used to study the flexural behavior of SBTSs with eight different recycled concrete aggregate (RCA) replacement rates, steel fiber (SF) contents, concrete strengths, and slab thicknesses, including damage modes, crack development, mid-span deflection, reinforcement strains, Concrete strain and profiled steel sheeting (PSS) strain. Increasing the replacement rate of RCA (ra) resulted in decreasing trends of the cracking, yield, and ultimate loads of the SBTS. The addition of SFs could improve the flexural behavior of the SBTS while improving the crack development pattern. Based on a calculation of ordinary reinforced concrete slabs, a modified calculation method applicable to SBTS using steel fiber-reinforced recycled concrete (SFRRC) is proposed, including flexural capacity, crack width, and flexural stiffness. Cost analysis and life cycle assessment showed that the application of SFRRC to SBTS can better balance environmental and mechanical performances, which is beneficial to the sustainable development of the construction industry.