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

本研究开发超音波量测系统，以评估早龄期混凝土之强度增益特性或劲度变化特性。该系统能够高精度、无损、连续、自动地测量早龄期混凝土的刚度变化，为了检验超声波测量系统的适用性，进行了大量的超声波波速评价早龄期混凝土刚度变化特性的试验。试验结果表明，基于超声波波速测量结果建立的三维阿氏图可以准确地评价早龄期混凝土刚度变化特性的温度依赖性。通过对超声波波速的连续测量，可以明确不同龄期混凝土刚度变化特性的细微差别，本研究开发的超声波测试系统作为早期混凝土刚度变化的一种新的测试方法，具有广阔的应用前景。

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.