PERFORMANCE PREDICTION OF WARM MIX ASPHALT PAVEMENT CONTAINING RECLAIMED ASPHALT PAVEMENT IN RHODE ISLAND

The warm mixed asphalt (WMA) technology has gained a lot of interests in the recent years in academia, state agencies and industries. WMA technology allows reductions in production and compaction temperatures guaranteeing relevant environmental and cost saving benefits. The purpose of the present study was to study and evaluate the performance of a typical additive in WMA pavement with Reclaimed Asphalt Pavement (RAP) on rutting, fatigue cracking and thermal cracking resistance on RI Route 102. In the present study, the asphalt binder was tested at different dosages of additive using Dynamic Shear Rheometer (DSR), Rolling Thin Film Oven (RTFO), Pressure Aging Vessel (PAV), Multiple Stress Creep Recovery (MSCR) and Bending Beam Rheometer (BBR). From the overall test, it was found that 0.7% additive would lessen pavement damage due to rutting, fatigue cracking and thermal cracking. Based on the results of binder test, Hot Mix Asphalt (HMA) and WMA specimens containing 20 % RAP were prepared using PG 58-28 asphalt binder and Superpave Gyratory Compactor (SGC). From the volumetric analysis of both HMA and WMA specimens, it was determined that the optimum binder content (OBC) for HMA with 20% RAP was 5.3 percent and the OBC for WMA (0.7% additive with RAP was 5.6%. It was found that the required amount of neat regular asphalt binder for WMA specimen was higher than the one required by HMA. HMA and WMA Specimens with each containing 20% RAP were prepared at OBC and indirect tensile (IDT) strength test were conducted on that specimen. The test indicated that the performance of HMA mixtures was better than WMA with same amount of RAP. RI Route 102 was used as case study in this research study. Route 102 was rehabilitated through Full Depth Reclamation (FDR) in 2015. First half road of RI Route 102 was built with HMA base and surface layer and the other half was built with WMA base and surface layer using a typical additive. It was found that both sections have similar value in Pavement Serviceability Index (PSI) and in International Roughness Index (IRI) at this time. Four specimens were prepared to predict the performance of asphalt pavement using the dynamic modulus and the master curve. Two HMA specimens each were prepared with and without RAP. Similarly, other two WMA specimens were prepared with and without RAP. These four specimens were tested with the Asphalt Mixture Performance Tester (AMPT) machine and developed the master curves for each specimen. The results of the material testing were used to predict the performance of each test sections by using AASHTOWare Pavement ME Design (PavementME) software. It was found that the WMA-RAP performed better in fatigue cracking resistance but was found to perform poor in rutting resistance than HMA and HMA-RAP. This indicated that fatigue cracking was not a problem with WMA-RAP mixtures whereas rutting resistance still requires further investigation and improvement.