Influence of applying overburden stress during curing on the unconfined compressive strength of cement-stabilized clay

In the case of cement-stabilized soils cured under the influence of overburden stress, it is necessary to consider two different timelines of cementation and consolidation, along which the structures of stabilized soils evolve. These two timelines are interrelated and ought not to be considered separately, especially in the early stage of curing when significant structural changes occur. In this study, the strength and deformation characteristics of cement-stabilized clay subjected to overburden stress during curing was investigated using an unconfined compression test apparatus. For this purpose, three types of specimens were prepared by stabilizing very soft clay with different amounts of cement. Overburden stress was applied for three different time durations during curing. In the series of unconfined compression tests conducted on the specimens with no overburden stress applied during curing, the axial stress initially increases rapidly, then was maintained before finally dropping. In the series of tests with overburden stress applied during curing, the axial stress continues to increase gradually before rapidly declining. The values of unconfined compressive strength are larger for the specimens subjected to overburden stress during curing. The values of the unconfined compressive strength also increase linearly as the duration of applied overburden stress increases. The increase in strength apparently occurs due to increasing dry density accompanied by a decrease in the water content due to the drainage of pore water during the application of overburden stress.