Evaluation of the mechanical behavior of pumice lightweight concrete reinforced with steel and polypropylene fibers

•Mechanical behavior of FRLWC with two type, shape and content of fibers is evaluated.•Strength, both fc and fct, is improved by a strongly depended on Vf*(l/d) magnitude.•Linear and power-type equations correlate strength with Vf*(l/d) and fc with fct.•Post-crack behaviour of FRLWC is strongly related to both the fiber type and shape.•Fibers govern the post-crack behavior, leading to improved residual strength. In the present paper, an investigation of the mechanical properties of fiber reinforced pumice lightweight concrete is attempted. In a reference lightweight concrete batch, four different types of fibers were added – three steel fibers (SF) of different length with hooks and one polypropylene fiber (PF), in two contents of 0.5% and 1.0% by volume. Typical compression and three-point bending tests were performed. As concluded from the experimental results, the use of fibers enhances the mechanical properties of the lightweight concrete, as it was found to considerably increase both compressive and flexural strength, while it was proved to be significantly beneficial during the post cracking phase.