Consolidation characteristics of a thermally cured sand–bentonite mixture

Shear Strength Characteristics of a Thermally Cured Sand-Bentonite Mixture

“…The trend of behavior for thermally cured samples was much similar to that of the structured or overconsolidated clays [34] or artificially structured soils [35]. It should be noted that a similar transition of behavior has been observed during the consolidation tests on the studied cured sand-bentonite mixture [7].…”

“…When the confining pressure increased to 500kPa, it was achieved in less than 24h at 20, 40 and 60°C. At 1000kPa, it was less than 24h only at 20°C and 40°C, however, it was less than 40h at all temperatures and confinements [7]. For this reason, the pre-curing times of 1, 3 and 5 days were chosen in present study.…”

“…Where, d  is the maximum dry density, mix s G , is the specific gravity of mixture and F is the weight ratio of clay to sand fractions. To obtain the most appropriate and impermeable protecting layer with minimum effective porosity, a 1:1 mixture by weight of silica sand and sodium bentonite was used [7]. The same ratio has been selected in other programs on HLW disposals in Germany as well as Canada [16].…”

“…The required time to finish primary consolidation of the applied mixed soil has been previously determined through isotropic consolidation tests by Shirasb et al [7]. The results showed that primary consolidation time increases with increase in temperature and confining pressure.…”

“…The SEM studies performed by Attah and Etim [6] on clayey sand also revealed that the initial porous structure of soil turns to a dense fragmented one after preheating to 150°C for 4 hours. Shirasb et al [7] investigated the effect of thermal pre-curing on consolidation characteristics of a sand-bentonite mixture and showed the transition of behavior from reconstituted to a structured one with a distinct yield stress. The yield stress increased with increase in curing time and curing temperature.…”