STUDY OF DISTANCE AND NUMBER OF REBARS ON VELOCITY MEASUREMENT USING NON-DESTRUCTIVE TEST

Abstract

The quality of constructions can be evaluated by using the non-destructive test (NDT) method, one of them is an ultrasonic pulse velocity (UPV) test. Velocity is one of the parameters that can indicate the density of the material that will affect the strength of the material. The difference in density of concrete and rebars could affect the velocity measurement of reinforced concrete. It is common knowledge as there are factors that affect the velocity measurement and some of them are the position of transducers and the number of rebars. An experiment was conducted to get a better understanding of the velocity measurement of reinforced concrete determined by the position of the transducers, the several rebars, and the distance between rebars and transducers using the UPV test. The specimens were reinforced concrete beams with different numbers of rebars, however, had the same tensile strength and diameter. The number of rebars used for specimens is 4; 8 and 12 rebars with the varied position of transducers. It can be concluded that the pulse velocity of reinforced concrete, when measured with a perpendicular position was ower than in the parallel position, and also the average transmission time in the parallel position, was 52% faster than the perpendicular. In the case of rebar parallel to pulse path, the velocity of reinforced concrete decreased as the distance between rebar and transducers increased, however, the number of rebars did not affect the velocity. On the other hand, in the case of rebar perpendicular to the pulse path, the number of rebars resulted in an insignificant effect on the velocity measurement (less than 1%).