Boundary effect of foamed cement paste under the influence of air-coupled impact-echo

Abstract

The air-coupled impact-echo method has been increasingly utilized for the detection of cement-based materials. In this study, an air-coupled impact-echo system is developed. This system evaluates the response of cast-in-place foamed cement paste blocks subjected to air-coupled impact-echo. The shape factor is calculated based on the acquired impact-echo spectrograms to analyze the boundary effects of the blocks. The results show that the values of the shape factor vary with the impact location, as the impact location from the edges of the blocks affects the air-coupled impact-echo response. Accordingly, a dimensionless factor is proposed to evaluate the boundary effect of block-like foamed cement paste. This study contributes to the application of the air-coupled impact-echo method for the detection of foam cement paste.