EVALUATION FOR SETTLEMENT CRACKS OF CONCRETE WITH TYPE FLY ASH BY NONDESTRUCTIVE TESTING

摘要

In order to clarify the extensibility of fresh concrete with typeIV fly ash which substitute for sea sand, visual inspection and ultrasonic method of nondestructive testing are performed to evaluate width and depth of settlement cracks of normal concrete and concrete with typeIV fly ash. As a result of this experimental study, it is observed by visual inspection that the average of settlement crack width of concrete with typeIV fly ash become as half as one of normal concrete in same covering By ultrasonic method, it is clarified that the crack depth of normal concrete agree approximately with one of concrete with type IV fly ash in the case of same crack width. In addition, it is confirmed that settlement cracks penetrate relatively nearer the reinforcement bar, as covering thickness become thinner.