Simulation experimental research on damage accumulation law of new concrete under multiple blasting vibration loads

To address the blasting vibration induced damage accumulation of new concrete,a test on blasting vi-bration induced damage accumulation of new concrete was carried out by the vibration test system,and the test of strength and durability of vibrated concrete was also carried out. The experimental results show that the blasting vibration induced damage accumulation has experienced three stages including the reduction stage, rapid growth stage and stability stage,and the cumulative damage value increases with the increase of vibration velocity. When the vibration velocity is less than 1． 0 cm / s,the development of ultrasonic wave velocity has experienced three stages including the rapid growth stage,slow growth stage and stability stage,the maximum ultrasonic wave velocity increases with the increase of vibration velocity,the damage deterioration effect of vibration loads does not appear,and the vibration loads can improve the com- pressive strength and durability of the concrete. However,when the vibration velocity is greater than 1． 5 cm / s,the de- velopment of ultrasonic wave velocity has experienced four stages because of the appearance of damage deterioration and reduction process,both the peak and steady ultrasonic wave velocity are lower than the corresponding wave velocity of the virgin specimens,and both decrease with the increase of the vibration velocity,the damage deterioration effect of vi- bration loads begins to appear in the second stage and appear macroscopically in the third stage,when the vibration ve- locity reaches 3． 5 cm / s,the damage deterioration effect appears from the first stage. The compressive strength and dura- bility of concrete are decreased,and the damage deterioration degree of high strength concrete is more obvious than that of ordinary concrete. Under the test conditions,the safety vibration velocity of new concrete should be controlled below 1. 5 cm / s,and the vibration velocity should not exceed 2． 0 cm / s before the age of 12 h.