Experimental investigation on effect of curing stress on the strength of cement-stabilized clay at high water content

The application of cement-stabilized marine clay at high water content (HW-CSC) as land reclamation fill has been receiving increasing attention and popularity. In current coastal development, HW-CSC land reclamation projects begin to advance toward deeper water areas, leading to greater filling heights and thus higher curing stresses acting on the lower portions of HW-CSC. In principle the higher curing stress will improve the strength gain of HW-CSC, but this curing stress effect is not taken into account in current design practice. This study aims to bridge the gap. Fifteen different mixes of HW-CSC are first prepared and cured in consolidation tubes for seven days under various curing stresses. Their strengths and some other post-curing parameters are then tested and analyzed to demonstrate the quantitative effect of curing stress on the strength gain of HW-CSC. Results indicate that the strength gain of HW-CSC is significantly influenced by the curing stress; however, the effect of curing stress cannot be simply replaced by reducing the remolding water content during mixing stage and letting the specimens be cured under atmospheric stress condition. Therefore, it is concluded that the effect of curing stress includes two different components-a consolidation effect and another effect termed the "self-stress" effect in this study. Finally, an empirical relationship accounting for the combined effects of mixing proportion and curing stress is developed for characterization of the strengths of HW-CSCs with different mixing proportions and various curing stresses. The proposed relationship is validated by three independent data groups collected from the literature. This empirical relationship can be helpful in optimization of mixing proportions of HW-CSC used for land reclamation purpose.