Toward a More Sustainable Pavement Preservation: Development and Evaluation of 100% RAP Microsurfacing Mixtures

Asphalt pavements undergo several distresses such as rutting and fatigue cracking under the influence of coupled effects of traffic and environmental loads. Use of reclaimed asphalt pavement (RAP) material into preservation treatments such as microsurfacing offers both economic and environmental benefits by ensuring natural resource conservation and cost savings with similar performance. The current research study emphasized utilizing 100% RAP material as a potential substitute for the virgin aggregates in microsurfacing. The study included laboratory investigations, construction of pavement test sections at New Jersey, monitoring the short-term performance, and conducting a performance-cost based comparison analysis. Results indicated that RAP can be used as a potential substitute to produce microsurfacing mixtures. RAP microsurfacing mixtures required 15% to 20% more water to achieve similar workability due to hydrophobic nature of RAP. Wet track abrasion test (WTAT) results showed enhanced abrasion resistance (22–28%) of RAP microsurfacing including partial RAP activation study. This phenomenon is also clearly visible through better rutting characteristics where RAP microsurfacing mixes exhibited 18%–25% lower lateral displacement values. Construction experience of virgin and RAP microsurfacing displayed an even, and consistent RAP mixture with no segregation of RAP particles. All the distress surveys conducted by research teams on pavement sections showed that RAP microsurfacing showed an equivalent performance compared to virgin microsurfacing. A cost difference of USD 38 per ton was observed for RAP microsurfacing compared to virgin microsurfacing which is around 11%. Performance and cost based relative comparison was found to be 94.5% and 99.3% for virgin and RAP microsurfacing.