Dynamic Stress and Strain of HPC Under Drop-weight Impact Loading

Studies have been done vastly to determine the dynamic stress-strain behaviour of concrete but the results seem not to agree with each other due to difference in method. The specimen size and the loading rate effects are significant factors in determining the compressive stress-strain behaviour of concrete cylindrical specimens. This study is to provide more dynamic stress-strain data that can add to that database on high performance concrete (HPC) using drop-weight impact test. Experiments on HPC cylinders were conducted for specimens with different sizes but maintaining the length-to-diameter (L/D) ratio (slenderness) of 2, and the results show that the maximum stress occurred for specimens with smallest size and decreased as the size increased. This current test shows that the apparent dynamic stress increase more than twofold compared to its static strength for small cylinder of Ø100 mm × 200 mm at strain rate 0.20 s^-1. It was found that compressive stress of HPC was seen to exhibit an enormously size effect under impact loading.