冲击回波法检测水工混凝土耐久性的试验研究

研究了冲击回波法用于混凝土棱柱体试件动弹性模量的测试情况，发现测试的波速为理论的一维P波波速，且获取混凝土动弹性模量的方法在本质上与传统的共振法是一致的。采用冲击回波法检测混凝土试件在冻融循环中波速的变化，与共振法测试的自振频率的变化进行对比研究，总结其内在规律，最终换算到相对动弹性模量的下降值来评价混凝土的抗冻性。初步的试验和理论分析的结果表明，利用冲击回波法进行水工混凝土抗冻性检测的方法切实可行，可用于水工混凝土的耐久性评估。

The durability of hydraulic concrete by means of impact echo method

This paper studies the validity of using impact-echo method to test the dynamic modulus of elasticity of concrete for standard prismatic specimens. It is found that the P-wave speed in a standard prism obtained from the impact-echo test well corresponds to the theoretical one-dimensional P-wave speed, and the dynamic elastic modulus obtained from the impact-echo method are essentially equal to those from the conventional transverse resonant frequency method. This paper adopts impact-echo method to detect the variation of P wave velocities of concrete specimen with the increase of freezing and thawing cycles, which is compared with the variation of fundamental vibration frequencies, thus to conduct parallel evaluation of the decline of relative dynamic elastic modulus using these two methods. The experimental results and theoretical analysis show that using impact echo method to detect the frost resistance of hydraulic concrete is feasible and can be used for durability assessment of hydraulic concrete.