Study on pore structure of coarse aggregate and drying shrinkage properties

Abstract

The factors which affect drying shrinkage of concrete are material properties and environmental conditions, and so on. It is said that the type of coarse aggregate is one of the most dominant factors which affect concrete drying shrinkage. It has also been pointed out that the pore structure of coarse aggregate affects drying shrinkage strain of concrete. From the above backgrounds, in this research, we focused on the pore structure of pore radius of 1 μ m or less for coarse aggregate and investigated the relationship between the coarse aggregate pore characteristics obtained by using mercury porosimetry and the drying shrinkage strain of coarse aggregate and concrete. For this study we used 10 types of crushed stone from different regions and of different qualities. As a result, we indicated a mutual relationship could be identified between the pore characteristics of coarse aggregate and the drying shrinkage strain of coarse aggregate or concrete when categorization by rock type was used. We also demonstrated that the average pore size of coarse aggregate, calculated from the pore characteristics obtained by using mercury porosimetry, was related to the drying shrinkage strain of coarse aggregate and concrete, and that it is possible that this relationship could be uniformly expressed by a power function.