Strength mobilization of cement-treated dredged clay during the early stages of curing

Abstract

Cement-treated marine clays have been widely used as a construction filling material in coastal engineering projects in recent years. The strength mobilization of cement-treated clay in terms of early stages of curing is important because the strength increases during the transportation and the placement to the construction site. In this study, to examine the characteristics of strength for cement treated clays during the early stages of curing, a series of vane shear and unconfined compression tests were carried out with varying water and cement contents for four marine dredged clays. On the basis of the results obtained from the laboratory tests, it was found that the strength mobilization process can be divided into two stages; first stage within 3 days after curing (the early stage of curing) and the second stage 3 days after the curing. Two equations to evaluate strength during early stages of curing were proposed based on the initial water content and specific volume ratio normalized by liquid limit. The equations consisted of coefficient a1, strength at 1h curing, and coefficient b1, strength increment ratio. It was found that the equation based on the specific volume ratio is slightly better in predicting the strength during the early stages of curing than the equation based on normalized water content. It is concluded that the proposed equations are very simple and useful to determine the strength of cement-treated clay during the early stages of curing.