Tomographic computational tool for concrete discontinuities identification using ultrasonic testing with synthetic data / Ferramenta informática tomográfica para identificação de descontinuidades do betão utilizando testes ultra-sónicos com dados sintéticos

Abstract

The presence of pathologies in concrete structures is a major problem for civil engineering, in particular when they are not located on the object surface. In this regard, digital tomographic reconstruction techniques have proved to be a great ally for the study of the internal structure of materials. Thus, this work aims to develop a computational tool combining tomographic techniques with the ultrasonic pulse velocity test to identify non-homogeneities within concrete structures. With this aim, the essential mathematical background for a better understanding of the tomographic problem, and the necessary steps for computational implementation are presented. The tomographic reconstruction algorithm was implemented in MatLab. To verify the effectiveness of the developed code, six simulated specimens were used representing internal sections of elements with discontinuities of different sizes and locations. Pulse propagation time vectors have been developed for horizontal, vertical, and composite reading configurations. To study the mesh dependency, meshes of 5cm x 5cm and 2.5cm x 2.5cm were used. The developed algorithm was able to create tomograms of the internal structure of the proposed elements. The results obtained both in terms of location and dimensioning of the discontinuities were best represented by the 2.5cm x 2.5cm mesh