Assessment of void and crack defects in early-age concrete

Abstract

Early-age voids and cracks can cause the mechanical qualities of concrete to deteriorate and impair its long-term operating performance. Therefore, it is crucial to detect and assess these problems at early ages. In this study, passive infrared thermography (IRT) and digital image correlation (DIC) techniques are used to study the temperature field and deformation field containing the defects. And the relationship between the geometric size of defects and temperature is investigated in conjunction with the finite element model. The results demonstrate that the subsurface void and surface void defects can be precisely identified and distinguished using infrared thermal imaging technology. The banded area radiating from the edge of the aggregate to the boundary, the connection between the aggregates, and the annular area surrounding the aggregate are where the majority of the large positive strain in the mortar is concentrated. These locations could develop cracks. Concrete voids will weaken the local mechanical properties, and increase the likelihood of local cracking when they are present in areas of large strain. The radius, depth, and thickness of voids are the geometric factors that influence the temperature difference, and there is a significant power function relationship between thickness × depth and temperature difference.