10 Pages

Sodium sulfate weathering in the residential concrete foundation

ByN. Yoshida, Y. Matsunami, M. Nagayama & E. Sakai

ABSTRACT: The salt weathering is one of the mechanisms of sulfate attack on concrete. Scaling of concrete surface arises from crystallization and hydration pressure of sodium sulfate which crystallizes in the pore of concrete. We have found several cases of salt weathering in the field investigations of residential concrete foundations constructed on the sulfatebearing ground, and also that the cases were widely seen in Japan. The analysis shows that the concentration of sulfate in the soil was observed in residential foundation, which made the sulfate environment severer. The laboratory experiment shows the deterioration of concrete similar to residential concrete foundation occurred. We focus on the influences of dry-wet cycle and the carbonation of cement matrix, presuming that they were one of the influential factors on salt weathering.