Laboratory freeze–thaw assessment of cement, fly ash, and fiber stabilized pavement foundation materials

Abstract

Freeze–thaw cycles in pavement foundation layers can cause rapid accumulation of pavement damage. To reduce the effects of freeze–thaw cycles, there is a need to characterize and design low frost susceptible foundation layers. This paper focuses on the laboratory frost-heave and thaw-weakening performance of pavement foundation materials that were stabilized with combinations of self-cementing class C fly ash, Portland cement, and polymer fibers. Additions of fly ash (15% by weight), cement, and cement + fibers presented improvement on frost susceptibility of soils. Grain size distribution and curing time and compaction delay of chemical stabilization influenced soil freeze–thaw performance. The heave rate has to be controlled to less than 4 mm/day to achieve very low thaw-weakening susceptibility per ASTM D5918. A proposed classification for chemically stabilized soils identifies thaw-susceptibility as negligible for post-test CBR values ≥ 100.

Keywords: Cement stabilization - Fiber reinforcement - Fly ash - Freeze–thaw - Frost-heave - Thaw-weakening