Effects of extended cycles of open system freezing and thawing on a clay-lime mixture

The purpose of this study was to evaluate effects of long term open system freezing and thawing on unconfined compressive strength of a lime-clay mixture and determine if length of curing has appreciable effect on strength and durability of the mixture.

Soil specimens were made by compacting the soil slightly above optimum moisture, quartering the extruded soil, using a lathe to bring the specimen to 1-3/8 inches diameter, and cutting specimens to 2-13/16 inches. Specimens were cured for two and four days, one half being curing for two days and the other half being cured for four days. Specimens containing zero and seven per cent lime were placed in open system freezing and thawing for 0, 5, 10 and 15 cycles of freezing and thawing, where one cycle consisted of 24 hours in a deep freeze unit and 24 hours in a 100 per cent humidity room at 70°F.

Unconfined compressive strengths were determined for all samples after freezing and thawing.

Results from the tests indicate the following:

1. Lime increased the strength of the olay soil used.

2. Lime increased the durability of the soil.

3. There was no appreciable difference in unconfined compressive strength for stabilized or unstabilized specimens cured for two or four days.

4. There was no appreciable difference in secant modulus between two or four day curing of unstabilized specimens, but prolonged curing increased the secant modulus of stabilized specimens.

5. Lime increased the secant modulus of specimens.