Recommended Method for Earlier Inspection of Concrete Quality by Nondestructive Testing.

Abstract

From a point of view that the rates of development of ultrasonic pulse velocity, dynamic modulus of elasticity, and rebound hardness are more rapid than the one of strength at early ages, experiments were carried out to obtain the optimum ages for nondestructive testing respectively.
It is concluded that the optimum age for ultrasonic method for evaluating potential quality of concrete is 1-day and the one for rebound hardness method is 3-day practically and the earlier the better. It is also concluded that the combined method is effective at early age.
Based on the results, a method combined 1-day pulse velocity with 3-day rebound number is ecommended for earlier inspection of concrete quality in structures.