Strength of Cement Treated Piedmont Residual Silty Soils

Piedmont residual soils form a strip that extends from Alabama to New Jersey and comprise much of Virginia, Georgia, and the Carolinas. Thus, a better understanding of their strength properties is of paramount importance. One of the hallmarks of the soils within the Piedmont region is its silty nature. Although it is usually a common practice to use lime treatment for highly plastic clayey soils, no such agreement exists on the type of soil stabilization when dealing with fine-grained silty soils. Hence, the effects of cement stabilization on the strength of residual silt were studied. California bearing ratio (CBR) and unconfined compressive strength (UCS) testing was conducted. The study showed that cement can react with the silty soil and the addition of cement can lead to further increase in strength. Equations were developed correlating liquid limit to CBR as well as cement content to UCS. A multi-variable model function was also proposed correlating CBR and cement content to UCS of treated soils, and equations were developed for silty soils with standard proctor CBR samples and 95% degree of compaction as well as modified proctor CBR samples and 97% degree of compaction. The accuracy of the proposed function was validated using data developed for cement treated lateritic sandy soils.