Determination of the Structural Coefficient of Different Combinations of Cement-Treated/Untreated Recycled Base Materials

Depletion of natural resources and adverse effect of construction waste and reclaimed asphalt pavement materials on environment has ignited the consideration of recycling and reuse of recycled concrete aggregate (RCA) and reclaimed asphalt pavement (RAP) as base material in pavement construction. The composition of recycled base materials vary significantly and mostly depends on the sources. The recycled materials utilized in this study was collected from the Texas Department of Transportation (TxDOT) approved sources. The amount of RAP and RCA varies from 0 to 100% in the combination at 20% interval. The objectives of this study are to determine optimum moisture content and maximum dry density, unconfined compressive strength tests and resilient modulus tests of different combinations of recycled materials at cement content varies from 0 to 6% at 2% interval. The optimum combinations of the different recycled base materials with cement were determined. Layer coefficients for the cement stabilized aggregates were determined to be used in the design of flexible pavements in accordance with the AASHTO design code. The results showed that the recycled base materials i.e., RAP and RCA mixed at optimum combination with 4% and higher cement content can be used as base material in flexible pavement.