The effect of pore water on the solidification of granulated blast furnace slag, called slag hereafter, and the design parameter evaluation method of solidified slag are discussed in this paper.
　The effects of pH and Ca2+ concentration on slag solidification are considered. Experimental results revealed that in the case of sea water as pore water, the pH was not enough high and the slag solidified. In the case of high pH NaOH pore water, the slag did not solidify over more than 90 days of curing, which is longer than the case sea water as pore water. These results show that not only a high pH but Ca2+ concentration affects slag solidification.
　To evaluate design strength parameters, the results of consolidated undrained triaxial compression tests for solidified slag and consolidated drained triaxial compression tests for undisturbed in-situ solidified slag were examined. The shear resistance of the solidified slag is composed of not only a cohesive factor but a frictional factor even when the consolidation pressure is smaller than the unconfined shear strength. The results indicate that the peak shear strength parameter for design should be composed of cd and φd.