Freeze-thaw performance of a cement-treated expansive soil

This experimental study presents an attempt on the effect of cement addition to expansive soil on its deformation and strength behaviours when subjected to freezing-thawing (F-T) action. A series of laboratory tests on cemented-treated expansive clay samples after 28-d curing periods were conducted. The experimental program involved freezing-thawing test, volume measurement, and unconfined compression test. The effects were evaluated by focusing on the water loss, volume change, stress-strain response, unconfined compression strength, resilient modulus and strain at failure after a sequence of freeze-thaw cycles. Eight groups of expansive soil samples were prepared with four different cement contents (i.e. 0%, 3%, 5% and 7% by weight of soil) and subjected to 0, 1, 2, 3, 5, 7, 9, and 12 F-T cycles, respectively. The analysis of experimental results indicated that 1) Cement additive makes expansive soil become less sensitive to moisture and cement-induced hydration reaction will reduce swelling-shrinkage characteristics triggered by F-T cycles; 2) The inclusion of cement within expansive soil causes an increase in unconfined compressive strength, resilient modulus, but a decrease in strain at failure. However, such effect induced by cement will be diluted by F-T cycles; 3) Cement can retard the degradation of resilient modulus but increase a faster strength reduction against F-T weathering. 4) Upon F-T cycles, un-cemented expansive soil will become more brittle, while cement-treated soils more ductile before 1st F-T cycle. A power function, independent of F-T cycles and cement contents, exists between the strain at failure and UCS. The results obtained from the study are fairly promising to employ cement additive against freeze-thaw resistance of expansive soils.