FIRST RESULTS OF SUCTION CONTROLLED OEDOMETER TESTS IN HIGHLY EXPANSIVE MONTMORILLONITE

The characterization of a highly expansive montmorillonite from Serrate de Nijar (Almeria, SE Spain) in unsaturated state has been accomplished. The "suction-water content" curve has been determined. Oedometric tests have been performed on cells with suction controlled either by nitrogen pressure or by sulfuric acid solutions. The tests have consisted of a drying-wetting or wetting-drying cycle at constant vertical load, followed by a loading-unloading cycle. The suctions applied ranged from 0.1 to 130 MPa, and the vertical loads from 0.05 to 5 MPa. At the end of the experiments the water content, dry density and pore size distribution of every sample are measured, in an attempt to relate the microstructure to the deformation behaviour. (A) For the covering abstract see IRRD 881647.