Study of the mechanical properties of clay containing smectite and carbonate

The correlation between physicochemical properties and mechanical behavior of clays is the subject of many studies [1,2]. The mechanical properties of clays are particularly significant insofar as they involve several disciplines, remediation, drilling muds, civil engineering, storage of toxic and radioactive waste. The smectite used in this work is from the southern west of Tunisia, particularly from Oued Tfal near the town of Gafsa is noted OT. Work included action on the characterization, physicochemical and mechanical properties of the raw clay treated with hydrochloric acid and purified. This work aims at studying the influence of pure clay fraction, including compensating cations on the hydromechanical properties of clay. The thermal study sample gives a percentage of 32.5% of carbonate in the raw clay. The elimination of carbonates by acid attack controlled the following results: If treatment by 0.5M represents a departure total of carbonates, there are probably altered layers of the clay fraction. To eliminate the excess of carbonate (6.03%), the sample was treated by 0.4 M HCl without deterioration of the structure of the silicate fraction. The hydromechanical study of three samples of raw clay (OT) purified (OTNa) and treated by (0.4M) hydrochloric acid put it clearly the relationship between the cation exchange capacity the percentage of carbonate and the swelling pressure.