DISINTEGRATION EFFECT OF ADDITIVES ON RED CLAYS UNDER DIFFERENT pH ENVIRONMENTS

摘要

To disclose the influence of different pH environments on the disintegration of red clay and improved red clays, this paper carries out disintegration tests on the red clay. Specifically, the red clay was separately improved by additives like calcium lignosulphonate (CL) and sodium lignosulphonate (SL). Then, the original red clay samples, CL-improved samples, and SL-improved samples were tested in three pH environments: 7, 2, and 12. The properties and micro mechanism of disintegration were observed carefully. The results show that the samples disintegrated in the form of peeling, rapid peeling and dissolution at the pHs of 7, 2, and 12, respectively. The additive-improved samples had longer disintegration time, and slower mean speed than the original red clay samples. The additives can improve the disintegration performance of the soil mass. Besides, the improvement effect of CL is better than that of SL, because CL has a much larger specific surface area. In the strongly acidic environment, the disintegration of red clay is mainly driven by physical action, and supported by chemical action. In the strongly alkaline environment, red clay disintegrates in two phases: violent disintegration driven by both physical and chemical actions, and uniform disintegration purely driven by chemical action.