INFLUENCE OF VARIABLES ON THE RESULTS OF NON-DESTRUCTIVE TESTS ON REINFORCED CONCRETE STRUCTURES

Abstract

The aim of this paper is to present the result of a study of the influence of some variables on the results of nondestructive testing of concrete, sclerometry (rebound hammer) and ultrasonic pulse velocity (UPV), specially in: Aggregates' size (DMA), concrete's moisture, casting concrete, and transducers' space. Moisture in concrete was obtained by controlled sprinkling water. The tests were conducted on six years old concrete blocks, and two years old reinforced concrete beams. Water/cement ratio of concrete blocks was maintained and DMA of coarse aggregates were 9.5 mm, 19.0 mm and 25.0 mm. The results of UPV revealed that blocks with the biggest DMA had lower UPV, the middle concrete layer presented bigger value of UPV than others. The UPV increased when the surface was sprinkled or the transducers space increased, for blocks and beams. The smaller rebound index was on blocks containing aggregates with the biggest DMA. For blocks and beams, the rebound index decreased when superficial moisture increased. Keywords: Nondestructive testing, ultrasonic pulse velocity, sclerometry (rebound hammer).