EXPERIMENTAL ANALYSIS OF QUASI DYNAMIC DAMAGE OF EARLY-AGE HIGH STRENGTH CONCRETE

In order to research internal damage and supersonic wave characteristic of early-age high strength concrete subjected to repeated load，cubic concrete samples were made in laboratory，demoulded and maintained in standard curing room． Cubic concrete samples were repeatedly compressed with their 50%，70% and 80% ultimate load at 1d，2d and 3d age respectively． Uniaxial compressive strength and supersonic wave velocity were recorded to be used to analyze the variation law of the samples before and after loading． The wave velocities of 7 d，14 d and 28 d cubic concrete samples were measured，and then compressed to crush． The results show that supersonic wave velocity increases with concrete age infirst 28 days，and has linear relationship with strength． Damage and variation law are different for the first 3 d age concrete samples subjected to different proportion ultimate load，which can be observed by uniaxial compressive strength and supersonic wave velocity． It is helpful to evaluate the accumulated damage law of early-age high strength concrete subjected to repeated blasting load in a blast project．