Experimental Research On Compressive Strength Test Of Humid Concrete With Nondestructive Methods

As a structural engineering material, Concrete has many advantages and is widely used in civil engineering field. In recent years, incidents generated from bad quality of concrete structures often occurred, and no doubt resulted in great loss for people living there. Therefore, it is necessary to detect existing concrete structures with nondestructive testing methods.This paper systematically introduces the existing nondestructive testing methods. Among the methods, because of the convenience and bargain price, rebound method and ultrasonic-rebound combined method are most widely used in testing practices. This paper also elaborates the testing principles of the two methods, and lists the influencing factors which can greatly affect the testing results.According to experiments of 81 concrete samples, we discover that the change of water content in concrete samples can greatly affect the testing results of rebound method and ultrasonic-rebound combined method. We also generalize relation curves between water ratio and testing results of the two methods. We put forward two formulas which can modify the testing results when the detected concrete structures are under water or in moist circumstance.One of the two formulas is use in two testing practices. The modified testing results exactly reflect the compressive strength of detected structural concrete. Therefore the formulas are proved reasonable and correct.