Seawater effect on consistency limits and compressibility characteristics of clays

The reported results in the literature indicate that there is a discrepancy regarding seawater effect on the consistency limits and compressibility properties of clayey soils having relatively low and high plasticity. To clarify this discrepancy, consistency limits including liquid, plastic and shrinkage limits, sediment volume and compressibility characteristics of ten soils were tested using distilled water and natural seawater from the Aegean Sea. The results indicate that the effect of seawater is negligible on the tested consistency limits and compressibility characteristics of soils when they have liquid limits up to 110%. The seawater effect is most noticed on the consistency limits and compressibility of Na-bentonites. The results of previous research were compiled and compared with those obtained in this study. All reported data were normalized by dividing the index values obtained using seawater by those obtained using distilled water. The comparison of data indicate that the compiled data and present study data are in good agreement, i.e. when the normalized values are plotted as function of liquid limit, all index properties plot along the unity line until the liquid limit of soils is about 110%; then, the normalized index values decrease almost linearly with liquid limit.