EXPERIMENTAL STUDY ON ONE-DIMENSIONAL STRESS SPALL OF UNIDIRECTIONAL REINFORCED CONCRETE

The one-dimensional stress spalling experiments were conducted on concrete and unidirectional reinforced concrete (UDRC) bars. The cylindrical bar specimenwith a large aspect ratio were loaded on a 74 mm diameter Hopkinson pressure bar loading platform. The displacement field and the strain field on the surface of the specimen were recorded by using an ultra-high speed video camera combined with a digital image correlation (DIC) system. The spall strength of both materials was measured, and the role of steel bar in the process of spalling was investigated. The results show that both the concrete and the reinforced concrete bar specimen stay in a one-dimensional stress state during loading, and therefore the one-dimensional stress wave propagation theory can be applied. The steel bar reinforcement in RC bar does not change the spall strength of the specimen, but maintain its structural integrity after matrix fracture. The spall strength of both concrete and reinforced concrete bars are basically identical, and have similar rate dependency.