Experimental Investigation on the Behaviour of Non-reinforced Ultra-High Performance Concrete Slabs

Abstract

Ultra-high-performance concrete (UHPC) is expected to provide solutions for the development of lightweight, high-strength, and rapid construction of concrete bridges due to its excellent material properties. In order to study the influence of steel fiber on the bending performance of non-reinforced UHPC (NR-UHPC) slabs, the bending failure test of 8 NR-UHPC slabs was completed with the steel fiber content as a parameter, and the failure mode, load-deflection, crack widths and load-strain curves of the test slabs were analyzed. The test results show that the destruction process of the NR-UHPC slabs can be divided into three stages: elastic stage, cracking stage and failure stage. The load-deflection curve and load-strain curve of the specimen with steel fiber content of 0.5%-1% change linearly during the elastic phase. In the elastic phase, the load-deflection curve and the load-strain curve of the test piece with a steel fiber content of 2%-3% were not smooth after the linearity begins; the strain of the UHPC slab was almost the same within 0-10 kN. However, as the load increased, the larger the amount of steel fiber was, the smaller the strain was, that is, the UHPC slab had good crack resistance. According to the regression analysis of test results at home and abroad, recommended design formulas for the bending bearing capacity of NR-UHPC slab were put forward, which tally well with the test results.