Assessment of physical and mechanical properties of concerete beams using PUNDIT Lab ultrasonic equipment

The purpose of this study is to conduct a non-destructive assessment of concrete beam specimens (experimental phase) and beams in an existing concrete structure (actual site inspection) through the use of Portable Ultrasonic Non-destructive Digital Indicating Tester, known as PUNDIT Lab. There are three methods of using the ultrasonic testing equipment, namely: the direct method, semi direct method, and indirect method. The equipment was used in cylindrical and beam concrete specimens having two designs mixes in order to determine the effects of the reinforcing bars and voids to the pulse velocity of the concrete. The pulse velocity determines the compressive strength of the concrete and the presence of voids in the beam specimens. Results show that direct and semi direct methods were the most reliable to use in determining the compressive strength of concrete, since the transmission of sound is through the surface as opposed to the indirect method in which the waves only propagate on the surface. Comparing the strength of pure concrete and reinforced concrete was impossible since the composition of unreinforced concrete is different from the reinforced one. It was found, however, that reinforced concrete with 10mm-diameter reinforcing bars has relatively no effects due to its small diameter. The induced voids with diameter of 38.1mm above were detected in concrete. Moreover, velocity decreases as the size of void increases. After the experimental phase, the testing of concrete beams in an existing structure was conducted. It was found that concrete uniformity varies at different points in the beam. The uniformity of concrete in the internal beams of an existing structure was represented by color-coded figures showing the lowest and highest velocities obtained per beam. This study provides experimental data for further comparison and reference to those who will be using the PUNDIT Lab. Since ultrasonic evaluation of structures in the Philippines is used infrequently, this study acts as an initiative for others to conduct structural assessment in concrete structure in the Philippine