The Effect of Freezing-Thawing Cycles on Performance of Fly Ash Stabilized Expansive Soil Subbases

This study describes the laboratory evaluation of the effect of freezing-thawing cycles on strength and swell potential of fly ash and randomly oriented fiber stabilized expansive soil subbases. Two high plasticity expansive clay soils were mixed with a Class C fly ash and artificial fibers, and then compacted to prepare specimens for all combinations for fly ash contents of 0%, 10%, and 20%, and a fiber content of 1%. After curing all specimens for seven days, the first set was subjected to unconfined compression tests, split tensile tests, and vertical swell tests. Similar tests were also conducted on another three sets of specimens after being subjected to 24 freezing-thawing cycles in a laboratory controlled environment. The freezing-thawing cycles significantly decreased the strength and increased the swell potential.However, the fiber inclusion minimized the potential for strength loss and swelling of expansive soil due to freezing-thawing cycles.