Thermo-mechanical behavior of uncemented and cemented sand-bentonite mixtures in elevated temperatures

Thermo-mechanical behavior of clays has been investigated in the past two decades because of increased interest in using clay as a buffer material in nuclear waste barriers. Many of researchers studied the thermo-mechanical behavior of clays to estimate their performance as buffers for nuclear waste containers [1-4].At present, sand-bentonite mixture is expected to be the most appropriate as a buffer material of high-level radioactive waste products when they are disposed in the deep ground resting place [5]. The dry density of pure clays can be as low as 1.3 Mg/m3 when compacted in situ; however, by mixing sand with the clay, the attainable dry density can be increased. Additions of sand can also be expected to decrease the creep potential of the material, increase the thermal conductivity and improve soil strength properties. Moreover, compacted clay-sand mixtures may possess lower hydraulic conductivities [6].The soil around nuclear waste repositories are subjected to elevated temperatures and their features change in long time. So response of the soil to coupled effect of pressure and temperature has been studied with more accuracy in last decades. This research tries to check the thermo-mechanical behavior of saturated sand-bentonite mixture in different temperatures and confining stresses during triaxial tests.