Effects of cement and lime addition to soft clays on their strength in saturated condition of Mahshahr Port

Document Type: Original Article

Authors

1 Department of Engineering Geology, Tarbiat Modares University, Tehran, Iran

2 Faculty of Basic Sciences,Tarbiat Modarres University, Tehran, Iran

Abstract

The surface sediments in Mahshahr Port area are mainly consist of soft clayey soils. These soils have considerable strength in dray condition but as their moisture content moves up to saturated level a notable decrease in their strength is observed. This reduction, in turn, leads to decrease of California Bearing Ratio (CBR) and increase in soil settlement which consequently results in vast and destructive deformation in the surrounding buildings. In this research, the addition of cement and lime to the soil is considered to evaluate their effect of the soil strength by performing unconfined compressive (UCS) and Atterberg Limits tests. In this procedure, different ratios of lime and cement mixture (0.0 %, 2 %, 4 %, 6 %, 8 %, 10 %, and 15 %) with various curing times is considered. The results of these tests revealed that compressive strength of soft clay decreases by adding lime or cement due to disturbing its initial structure. This decrease of strength is induced by high sensitivity of the soil, however as the time passes compressive strength of the cement-added samples rapidly grows; as compressive strength in modified samples with 6 % cement and curing time of above 3 days has increased compared to undisturbed samples and their plasticity index has decreased. On the other hand, compressive strength of samples modified by lime gradually increased, as adding 6 % lime to the soil and applying curing time of 28 days did not lead to increase of their compressive strength compared to undisturbed soil samples and their plasticity index decreased.

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