Research on the Evaluation Method of Strength Gain or Stiffness Change Property of Early Age Concrete by Ultra Sonic Wave Velocity

在本研究中，我们开发了超声波测量系统，用于评估早龄混凝土的强度增益特性或刚度变化特性。该系统能够高精度、无损、连续、自动地测量早龄混凝土的刚度变化。为了检验超声波测量系统的适用性，进行了大量利用超声波速度计评价早龄混凝土刚度变化特性的实验。这些实验结果表明，根据超声波速度的测量结果创建的3维阿伦尼乌斯图可以准确地评估早龄期混凝土的刚度变化特性的温度依赖性。刚度变化特性的微小差异可以通过连续测量超声波速度来阐明。本研究开发的超声波测量系统作为早期混凝土刚度变化的新测量方法非常有前景，并且可期待其在各种用途中的应用。

In this research, we developed ultrasonic measurement system for the evaluation of strength gain property or stiffness change property of early age concrete. This system can measure a stiffness change of early age concrete with high accuracy, nondestructive, continuously and automatically.In order to check the applicability of ultrasonic measurement system, much experiments which evaluate stiffness change property of early age concrete by ultrasonic wave velocity ware conducted. From these experimental results, it was shown that temperature dependency of stiffness change property of early age concrete can be exactly evaluated by 3-dimensional Arrhenius plot which created based on the measurement results of ultra sonic wave velocity. The slight difference in stiffness change property can be clarified by continuous measurement of ultra sonic wave velocity.The ultrasonic measurement system developed in this research is very promising as the new measurement method of stiffness change of early age concrete, and the application for various purposes is expectable.