FUNDAMENTAL STUDY OF SCALING RESISTANCE EVALUATION BY DRILLING POWDER

Abstract

 As a fundamental study to establish a method for evaluating the scaling resistance of concrete in a short period of time based on the analysis of drilling powder, the correlation between the scaling resistance of cement paste and mortar and the pore volume evaluated by drilling powder was investigated. The pore volume in the drilling powder was measured by mercury intrusion porosimetry. For cement paste, the scaling resistance sharply decreased when the pore volume evaluated with drilling powder exceeded around 0.20 mL/mL, regardless of the water to cement ratio or the entrained air volume. In addition, for mortar, a method for evaluating the pore volume of the cement paste portion in the hardened matrix by applying heat treatment and acid dissolution treatment to drilling powder was proposed. As a result, it was observed that the scaling resistance of mortar specimen sharply decreased when the pore volume of the cement paste portion which were evaluated by proposed method exceeded around 0.18 mL/mL. These results suggest that the scaling resistance of cementitious materials can be estimated even from fine drilling powder.