Abstract
By replacing the blast furnace slag fine aggregate with natural fine aggregate, hardening properties improving effect, such as long-term strength enhancement, drying shrinkage reduction, and carbonation inhibition of concrete is known to be obtained. In this study, for the purpose of revealing the mechanism of hardening properties improvement of blast-furnace slag fine aggregate, we focused on the difference in particle size of the blast-furnace slag fine aggregate, and investigated the influence of each particle diameter on properties of hardened mortar. As a result, it was found that blast-furnace slag fine aggregate is effective in strength enhancement and drying shrinkage reduction as particle size is small, and particle size smaller than about 0.045 mm is more effective. Next, we confirmed the influence that content of the particle size smaller than about 0.045 mm gave to properties of hardened concrete. As a result, it was found that the compressive strength is remarkably enhanced, and effect on drying shrinkage and carbonation was small by adding about 5% of blast furnace slag powder as the particle size smaller than about 0.045mm.
