Chemical influence on water retention behaviour of compacted bentonite

Abstract

This present study investigated the chemical influence on the water retention curves of compacted GMZ bentonite. Sodium chloride solution and calcium chloride solution were mixed with the bentonite before compaction. Water retention curves were determined by measuring suctions with a the high-precision humidity sensor. The chemical influences on water retention curves were predominant in the suction range less than 70 MPa. In the suction range, an increasing of solution salinity resulted in an upward movement of water retention curve, i.e. an increasing of water retention capability of the bentonite. The solution type also had notable influence on the water retention behaviour. A higher water retention capability of the bentonite added with calcium chloride solution was observed compared to that with sodium chloride solution. In the suction range larger than 70 MPa, the influences of the solution type and salinity on the water retention behaviour were insignificant, and the water retention curves with different solutions were almost identical.