Flexural performance of conventional and reactive powder concrete built–up beams

Abstract

This paper presents an experimental investigation on the flexural behavior of reinforced concrete beams made from a combination of two types of concrete as a (built-up or composite) member. The experimental program consists of casting and testing of eleven rectangular cross-sections of simply supported reinforced concrete beams. Distribution of the specimens was three beams used as a reference which were fully poured from conventional concrete (CC) and reactive powder concrete (RPC). The remaining were eight (built-up) beams made by incorporation of two types of concrete as an element, about those beams, the RPC is poured as layers different in depth and the effective regions (compression and tension), where they are compatible with CC to complete the beam depth. Experimental results show that a stiffer behavior of load-deflection appears, especially when the RPC is in tension region (the bottom of the beam) with respect to increase of the layer depth and the volumetric ratio of steel fibers (vf). The load-carrying capacity of (built-up) beams increase when the RPC is used in the compression region affected by the increase of the layer depth and the volumetric ratio of steel fibers, with less stiffer behavior compared to the beams where the RPC used in the tension regions. The results can be summarized that RPC utilizing in compression regions is more influential than utilizing it in tension regions.