Soil Solidification with Ultrafine Cement Grout

Since they first appeared in Japan about 30 years ago, ultrafine cements have become commonly available. Grouts containing these cements can be formulated to permeate most any granular soil including fine sand. In this application, they have substantial advantage over the more traditionally used chemical solution grouts, in that significantly higher strengths can be obtained, and at a lesser cost Additionally, cement grouts are non-toxic and do not suffer strength regression with time, as do most chemical grouts. Ultrafine cement can be of any one of three different origins, including common portland cement, slag based cement, and a combination portland-pozzolan blend. However, there are fundamental differences in the penetrability of grout derived from the cement of these different origins. Extensive research and experience has shown the grain size of the cement alone does not control the penetrability of the resulting grout into soil. Both grain shape and surface condition of the cement are important, as is the polar intensity. The results of an ongoing evaluation program, as well as actual case histories of projects utilizing ultrafine cement grout are presented.