PERFORMANCE OF RECYCLED MIXTURES IN STATE OF GEORGIA. FINAL REPORT

The Georgia Department of Transportation (GDOT) has been constructing recycled asphalt pavements routinely for about four years. This research project was undertaken to evaluate the performance of recycled pavements in comparison to virgin (control) asphalt pavements. Five projects, each consisting of a recycled section and a control section, were subjected to detailed evaluation. In-situ mix properties (such as percent air voids, resilient modulus and indirect tensile strength), recovered asphalt binder properties (such as penetration and viscosity), and laboratory recompacted mix properties (such as Gyratory Stability Index and confined, dynamic creep modulus) were measured. A paired t-test statistical analysis indicated no significant differences between these properties of virgin and recycled mix pavements which have been in service from 1 1/2 to 3 1/2 years. Ten additional virgin mix pavements and 13 additional recycled pavements were also evaluated as two independent groups. No statistical differences were found between the recovered asphalt properties (penetration and viscosity) of these virgin and recycled pavements in service. The current GDOT recycling specifications and mix design procedures appear to be satisfactory based on the results of this study.