三向等压荷载历史后混凝土超声波探伤方法研究

采用两组混凝土立方体试件,对其施加三向等压荷载历史作用,分别测量载前和载后的抗压强度、劈拉强度和超声波速.首先研究了经历过三向等压荷载历史后超声波速的劣化以及混凝土强度与声速的关系.然后,用抗压强度和抗拉强度的劣化来定义混凝土的损伤,研究了损伤与超声波速降低的关系.根据试验数据拟合得到损伤的演化方程,从中可以看出损伤与超声波速的降低之间具有较好的线性相关性,且有明显的超声波速降低临界值.研究表明,根据超声探伤方法测得的声速,结合混凝土经历的荷载历史和配比等因素,可以为工程提供较为可靠的损伤估计值,对实际工程的指导意义重大.

Supersonic Inspection for Concrete Due To Triaxial Equi-compressive Loading History

Triaxial equi-compression test of two sets of concrete with different strength has been carried out.The compressive strength,splitting tensile strength and ultrasonic velocity are measured before and after loading history,respectively.Based on the continuum damage mechanics theory,the reduction of compressive strength and splitting tensile strength denote the damage of concrete.The effect of triaxial equi-compressive loading history on the ultrasonic velocity and the relation between the strength and the ultrasonic velocity are investigated.In addition,the relationship between the damage and the descent of ultrasonic velocity is also studied.According to the fitting of experimental data,the evolution equation of damage is obtained.The damage is found to be in linear dependence relationship with the descent of ultrasonic velocity.It is concluded that,being an important nondestructive detection method,supersonic inspection is convenient and applicable to estimation of damage of concrete during loading history in engineering practice.