关键词: 爆破振动, 新浇混凝土, 损伤累积, 超声波波速, 模拟试验

Abstract: In order to reveal the blasting vibration damage accumulation mechanism of fresh concrete, the authors designed and carried out blasting vibration damage accumulation simulation experiments, tested the ultrasonic wave velocity and calculated the damage value. The experimental results show that the ultrasonic wave velocity change experiences four stages under repeated frequently blasting vibration load, they are a rapid growth stage, a slow growth stage, a damage degradation lower stage and a stable stage, that the ratio of reducing ultrasonic wave velocity decrease rapidly in the first stage, blasting vibration promotes the development of fresh concrete strength, but the ratio of reducing ultrasonic wave velocity begins to increase sustainably from the second stage, and the damage deterioration effect appears, the blasting vibration damage increases rapidly first, then increases slowly and tends to be stable with the increase of the vibration times, that both the peak wave velocity and steady ultrasonic wave velocity are lower than that those in the datum concrete, and the damage degradation of high strength concrete is more obvious than that of the ordinary concrete, and that the blasting vibration damage accumulation of fresh concrete is the results of native micro crack tip local damage deformation and the micro cracks and mesoscopic crack propagation.

Key words: blasting vibration, fresh concrete, damage accumulation, ultrasonic wave velocity, simulation experiment