STRUCTURAL COMPARISON OF TWO COLD RECYCLED PAVEMENT LAYERS

The structural strengths of two cold recycled pavements are compared. One recycled pavement section was built with foamed asphalt as a binder and the other with emulsion as a binder. Cores and deflection measurements were taken at different times after construction. The comparisons were based on results of tests on the cores, Dynaflect deflections, and strength indicators as well as developed AASHTO layer coefficients. The comparisons showed that the stiffness and strength of both recycled sections increased during the first 400 days after construction. The strength of the foamed-asphalt section increased more rapidly than than that of the emulsion section during the first 250 days. The strengths and stiffnesses of the foamed-asphalt recycled section were slightly higher that those of the emulsion recycled section during most of the evaluation period, but the differences were small. Ranges of layer coefficients were developed that can be used in design of similar layers. These ranges indicate that the two recycled layers should perform about the same. The initial cost will therefore be the controlling factor in an economic analysis of these two types of recycled pavements.