Behavior of Reinforced and Posttensioned Concrete Members with a UHPFRC Overlay under Impact Loading

Abstract

The impact response of reinforced and posttensioned concrete members with ultrahigh-performance fiber-reinforced concrete (UHPFRC) overlay was studied. This paper presents the results of nine drop weight slab strip tests. Major parameters for the tests were the reinforcement configuration of the concrete substrate, the addition of reinforcing bars in the UHPFRC layer, and the static system. Two reinforced and posttensioned concrete slabs were tested for reference. Five slab strips were tested under static loading conditions for comparison. A three-point bending and a cantilever system were used in the drop weight tests to induce flexural compression or tension in the upper UHPFRC layer. The addition of a UHPFRC overlay improved the structural response: no crushing or spalling occurred in the UHPFRC at the impact location. The UHPFRC had a load distributing function, which led to reduced crack widths in the substrate and lower member deflections.