Volume 40, Issue 3 (May 2012)
Evaluation of Durability of Stabilized Clay Specimens Using Different Laboratory Procedures
In this comprehensive laboratory study, different tests—namely, investigations of the unconfined compressive strength (UCS) at the end of freeze-thaw/wet-dry (F-T/W-D) cycles, the resilient modulus (Mr) at the end of F-T/W-D cycles, vacuum saturation, and moisture susceptibility—were used to evaluate the durability of cementitiously stabilized subgrade soils. Two fat clays commonly encountered as subgrade soils in Oklahoma, Dennis and Lomill series, were utilized. These soils were stabilized with 6 % hydrated lime (or lime), 10 % class C fly ash (CFA), or 10 % cement kiln dust (CKD). Cylindrical specimens of three different sizes were compacted and cured for seven days. Then, Harvard miniature specimens were tested for UCS at the end of F-T/W-D cycles and moisture susceptibility (five-hour soaking). Additionally, cylindrical specimens were tested for Mr at the end of F-T and W-D cycles to evaluate the effect of F-T and W-D cycles on Mr. Furthermore, Proctor size specimens were tested for UCS after vacuum saturation. All the specimens showed a decrease in UCS values at the end of F-T cycles and vacuum saturation. In general, all the specimens tested in this study showed an increase in UCS values at the end of one W-D cycle. The Mr values of both raw and stabilized soil specimens were found to decrease with an increase in the number of F-T or W-D cycles. Both soils showed the maximum resistance to F-T and W-D cycles after being stabilized with 6 % lime, as compared to 10 % CFA and 10 % CKD. A similar trend was evident in both moisture susceptibility and vacuum saturation tests.