Bond conditions in wall-type steel-reinforced self-compacting concrete element

Abstract

This work looks into the variations in the bond conditions between steel and self-compacting concrete (SCC). The bond conditions along the height and span of wall elements are compared with column and beam elements. The study involved pull-out bond tests and compressive strength tests on module samples derived from a wall element having 2240 × 160 × 1600 mm in length, width and height, respectively. SCC mixture casting was performed from a single point located at one of the short edges of the element. The pull-out tests were conducted on samples having deformed steel rebars with a diameter of 16 mm. We examined in detail the top-bar effect occurring across the entire wall element. The bond strengths at different heights within the element were compared to that at its bottom. On average, the reduction in the bond strength was 22%, and as much as 39% at the top of the wall. The bond strength increased by an average of 13% within the end part of the element as a result of the rebound effect. The phenomenon of bond strength reduction with an increasing depth of concrete under a reinforcing bar seems universal across different types and heights of elements.