Importance of Soil Pulverization Level in Lime Stabilized Soil Performance

In this study, effects of soil pulverization level on mechanical properties of a lime stabilized high plasticity clay were investigated. Unconfined compression strength tests were carried on lime stabilized samples which were prepared with two different soil pulverization levels. Fine soil pulverization consisted of 100% finer than No.4 sieve, as typical of laboratory applications. Coarse soil pulverization consisted of 60% of the soil passing No. 4 sieve and all finer than 20 mm, as typical of a high quality field gradation. 4%, 6% and 9% hydrated lime were used by dry weight of the soil for soil stabilization. Unconfined compression tests were carried out after 7, 28 and 56 days of curing. The results revealed that stress-strain behavior differed with soil pulverization levels. Unconfined compression strength and initial modulus values were also significantly affected by soil pulverization levels. Coarse pulverized samples had considerably inferior unconfined compression strength and initial elastic modulus values. This was valid for all curing days. The ratio of values obtained for fine and poor soil pulverization ranged between 1,5 to 2 for unconfined compression strength values and was about 1,5 for initial elastic modulus values. These differences may cause discrepancies between laboratory-estimated and actual field performances of the pavements. It should also be recalled that, in case, field soil gradations are coarser than that of this study, the differences may be larger. Therefore based on the results of this study, it is recommended that laboratory testing for mixture design of lime stabilized soils should be carried out with probable field gradations.