ANALYSIS ON BEARING CAPACITY AND BEHAVIOR OF REACTIVE POWDER CONCRETE WITH EMPTY CONCENTRIC DUCT UDER LOCAL PRESSURE

The reactive powder concrete (RPC) block with an empty concentric duct was used to simulate the anchorage zone concentratedly loaded by post-tensioned tendons. Nine specimens were built and loaded monotonically to failure. All specimens cracked and failed suddenly and brittely. The first cracks were found on the side face of specimens. These cracks longitudinally extended to the near height of specimens, and their widths were larger in the middle part than in both ends. Cracks developed and RPC falled out continuously near to failure. The failure model is splitting with following cracking. Contrast to specimens without ducts, the duct evidently weakened the local wedge zone ahead of a bearing plate. It results in specimens-cracking slowly and decreases local bearing capacity. The local bearing capacity of a RPC block with an empty duct is dependent on two critical parameters directly related to the geometry of the zone. One is the ratio of the net area of RPC supporting the plate to the area of the bearing plate. Another important parameter is the ratio of the diameter of a duct to the side length of the local pressure. An expression of the local bearing capacity of RPC with an empty concentric duct is proposed on the basis of experimental results.