Effect of Lime Treatment on Collapse-Susceptible Soils in Tucson, Arizona

This paper presents the results of a laboratory study conducted to determine the effectiveness of lime treatment in modifying the volume change behavior of a typical collapse-susceptible soil in Tucson, Arizona. A series of specimens containing 3% by weight of lime was prepared by statically compacting the mixture to maximum dry density at optimum moisture content as determined by ASTM D 698-78. Specimens were moist-cured under controlled conditions for from 0 to 7 days so that the effects of curing time could also be studied.

Following curing, specimens were tested in an oedometer to determine both “free” swell potential and collapse potential under either 47.9 or 191.5 kPa (0.5 or 2.0 ton/ft²) of applied normal stress. The results of these tests were compared with the results of similar tests performed on specially preconditioned, undisturbed samples and untreated, compacted specimens loaded under the same conditions. The comparison indicates that even moderate lime treatment substantially modified the collapse and free swell characteristics of the compacted soils and significantly improved their engineering behavior.