Residual Punching Strength of NSC, HSC and LWC Panels Exposed to High Temperatures

Abstract

This work aims at studying the post – heating behavior of normal strength concrete (NSC), high strength concrete (HSC) and lightweight concrete (LWC) slabs and assessing the residual punching shear strength of two-way slab specimens. Eleven reduced scale reinforced concrete slab specimens divided into three main groups, each of which is divided into subgroups for heating levels, representing the NSC, HSC, and LWC types of corresponding cube compressive strengths of 50, 94 and 37 N/mm² respectively, are prepared in the laboratory. Residual punching shear strengths, load–deflection curves, crack patterns, failure characteristics and details, and effects of temperature level exposure are all recorded, investigated and discussed. Effects of concrete type and structural failure type when slabs are exposed to different temperature levels are also discussed. Results indicate a reduction of strength with exposure to high temperature. Residual punching strength percentages at maximum temperature exposure are 33.3%, 53.8% and 69.2% for NSC, HSC and LWC slabs, respectively.