Visualization and quantification of water penetration in cement pastes with different crack sizes

Abstract

Cracks promote the rapid ingress of water into concrete and shorten the service life of concrete structures. As different deterioration factors form cracks of different sizes, it is necessary to study the water penetration mechanism in cracks. In this study, the capillary absorption process of cement pastes with different crack sizes was monitored by X-ray radiography. With the image processing method of X-ray radiography, a two-dimensional distribution of water during the absorption process was precisely quantified. It was found that cracks provided a direct path for water diffusion and made the water distribution uniform. As the crack width decreased, capillary rises in cracks became higher, which increased the water content along the crack direction. Although water absorption started in two dimensions due to cracks, with the progress of the water absorption process, the influence of cracks decreased, and the absorption of the whole sample could be regarded as one-dimensional.