The main objective of this study was twofold: 1. To determine the effect of freezing and thawing on the loss in strength of lime-soil mixture. 2. To investigate the effect of the addition of an air entraining agent on the freezing and thawing durability of lime-soil mixtures. For the first part, twelve specimens were prepared for each of 0, 5, 10, 15 and 20 percent combination of lime-clay mixture, giving a total of 60 specimens. For the second part, twelve specimens were prepared for each of 0, 5 and 10 percent of lime, giving a total of 36 specimens. Those containing five percent were treated with 4, 6, 8, 10 and 12 drops of air entraining agent for each two specimen batch, while those containing 0 and 10 percent were treated with 4, 7, 10, 15 and 20 drops. All specimens were wrapped with aluminum foil and immediately sealed with paraffin and cured for two days at 120°F. Control specimens were placed in the 70°F environment for ten days while companion specimens underwent five and ten cycles of freezing and thawing. The results of this study indicated the following: 1. Addition of lime increases the strength of clay soil. 2. Maximum percent increase in durability of clay soil found to occur with addition of ten pero.ent lime. 3. The decrease in strength due to freezing and thawing mainly occurred during the first five cycles. 4. Seven drops of air entraining agent gave maximum strength of air entrained specimens. / Master of Science