USE OF ADDITIVES AND EXPANSIVE CEMENTS FOR SHRINKAGE CRACK CONTROL IN SOIL-CEMENT: A REVIEW

The mechanisms and factors affecting shrinkage and cracking in soil-cements are reviewed. Secondary additives that have been found to be effective in reducing shrinkage and/or decreasing cracking are reported, with emphasis on the mechanisms involved. The use of expansive cements in concretes and in soils is presented, and other promising additives and approaches are also suggested. Although drying shrinkage is primarily responsible for inducing cracking in soil-cement, shrinkage and cracking nonetheless do not go hand-in-hand with each other. Factors such as geometric and restraint characteristics of the soil-cement layer, tensile properties of the soil-cement, and environmental factors such as mixing, curing and temperature also control the development of the shrinkage stresses and cracking behavior of the soil-cement. Most of the results reviewed are based on laboratory studies. Because of the diversity of factors present in the field, more field experiments and data are needed before secondary additives and expansive cements can be used with confidence in shrinkage crack control in soil-cement.