Abstract:
Sustainability and durability are the key requirements of pavement structure. Warm Mix Asphalt (WMA) technologies are utilized along with addition of Reclaimed Asphalt Pavement (RAP) for sustainable asphalt pavement structure, where durability of asphalt involves performance parameters like fatigue and fracture resistance properties etc. Utilizing high percentages of RAP in asphalt mix increase the mixing and compaction temperature which may degrade the performance of asphalt. For reducing production temperatures of Hot Mix Asphalt (HMA) many new processes have been searched out keeping in view the quality assurance of resulting pavement structure, among these processes’ addition of Sasobit as a WMA additive to decrease mixing and compaction temperature of asphalt mix containing RAP is the most famous one nowadays. The present research work evaluates the fatigue and fracture performance of HMA and WMA having varying percentages of RAP. Different mixes of WMA and HMA were designed with varying percentages of RAP (0%, 20%, 40% and 60%) through Marshall mix design using 60/70 penetration grade bitumen from two different sources. The best one was selected on the basis of their volumetric properties for preparing samples for performance tests. Sasobit (organic/wax-based additive) was used as WMA technology to prepare WMA at varying percentages (0%, 2%, 4% and 6%). The fatigue behaviour of asphalt was evaluated using four-point bending test, where asphalt resistance to fracture was determined using Semi Circular Bending (SCB) test in the laboratory. Results obtained clarify that Fatigue and fracture resistance of WMA were improved with the increase in percentages of Sasobit and RAP content, while the addition of RAP in HMA showed a decreasing trend of fatigue and fracture resistance due to the stiffer nature of RAP. Furthermore, WMA was identified as economical for construction besides other benefits like improved properties and environmentally friendly asphalt mix. The use of such technology is very beneficial to be incorporated in pavement construction industry, mostly in case of developing countries like Pakistan as reducing of production temperatures will provide many other benefits like reduced emission making it environmentally friendly, reduced cost of fuel make it economical, will also result in wider window for paving in winter season.
