Stabilisation of Expansive Soil Against Alternate Wetting–Drying

Abstract

Expansive soils widely deposit in major areas of Adelaide of South Australia. The soils tend to expand as they absorb a volume of moisture and shrink when a portion of the moisture escapes. The alternate changes in volume of the soil pose severe damage to foundations of residential and commercial buildings. A solution is to amend the expansive soils by stabilisation. The stabilisation becomes less effective over time, in particular, when the soils are exposed to cyclic wetting–drying impact due to seasonal changes which regularly occur in Adelaide. Laboratory investigations were conducted to examine the stabilisation durability. Expansive soil was stabilised by three separate additives, i.e. cement, lime and fly ash. These additives were included at different doses, aiming at determining the choice of suitable additive and optimising the feed. Stabilised soil samples were exposed to cyclic wetting–drying conditions. Swelling and shrinkage of the samples were measured in the course of the cyclic processes. Some interesting results were presented.