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

- Mixing 15% fly ash with CL improved frost-heave and thaw-weakening.
- Cement with fibers improved SM to negligible frost susceptibility.
- Frost susceptibility as negligible when post-test CBR values ≥ 100 was proposed.
- It is difficult to predict the post-test CBR values from the pre-test measurements.

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.