The dynamic stress-strain characteristics of a Pressurized Fluidized Bed Combustion (PFBC) material, before and after freeze and thaw cycling, were studied to evaluate its suitability as a substitute for conventional road construction materials in the design of flexible pavement systems. Samples compacted in the laboratory at two different moisture contents (optimum and 8% above optimum) were cyclically load tested after being allowed to cure for various durations. The results of the cyclic tests are presented in terms of the Resilient Modulus, which is a measure of the elastic property of the soil supporting the roadway. The modulus of the samples compacted near the optimum moisture content compared satisfactorily with data available for conventional materials. Samples compacted at moisture contents higher than the optimum exhibited a significant reduction in resilient modulus values after freeze-thaw cycling. This comparison indicates that properly compacted PFBC holds good promise as a subgrade material in the construction of low traffic volume roads.