Effect of Salinity on Rheological Behavior of Cement-Treated Dredged Clays as Fills

Abstract

The rheological behavior of dredged clays at various pore water salinities treated with portland cement was investigated for beneficial use in structural fill applications. The focus was on evaluating the effect of salinity on flowability and viscosity of dredged clays as fills. Flow and viscosity tests were conducted on clay specimens at high water contents prepared using a sodium salt solution at various salinities and blended with cement in different proportions. Results suggest that the increase in salinity can reduce the liquid limit and viscosity while increasing the flowability. The slump flow value systematically increases with the increase in salinity. All specimens exhibited Bingham plastic behavior when the shear rate was greater than approximately 10 s−1. The two parameters of the Bingham plastic model including dynamic viscosity and yield stress consistently decrease with increasing salinity. Moreover, the two parameters were found to markedly decrease with salinity when salinity is less than 4% and less significantly when salinity exceeds 4%. The empirical power-law function between dynamic viscosity and liquid index cannot fully characterize the viscosity of cement-treated dredged clays at various salinities. Two power function curves can be fit to data of slump flow values corresponding to two parameters, indicating that the slump flow uniformly decreases with the increase in each parameter.