On the soil stabilization of Terra Rossa

The soil stabilization of highway subgrade and base course is able to classify the following methods by the kinds of additives : (1) Mechanical soil stabilization, (2) Soil stabilization with cement, (3) Soil stabilization with bitumen, (4) Soil stabilization with chemicals. Three kinds of soil stabilization with cement, bitumen and chemicals are adopted in our experiments. The soil sample is terra rossa, which is so widely distributed to Carust terrace at Mine and Akiyoshi districts. The percentage of clay in this soil is 43,liquid limit is 74.6 and plastic index is 42.5. It is generally said that the soil in which the percentage of clay is more than 30,liquid limit is more than 40 and plastic index is more than 18,is difficult to be stabilized economically. In this point of view, Terra rossa is a very interesting soil. There are various methods testing the effect of soil stabilization, but unconfined compression test, Marshal test and modified CBR test are tried in our experiments. The results of these experiments are mentioned in this paper.