Mechanical evaluation of recycled aggregate mixes and its application in reclaimed asphalt pavement (RAP) stretch

Background The depletion of natural resources has led to the need of looking out for alternatives of primary construction materials. The use of reclaimed asphalt pavement (RAP) has become a common practice as it reduces economic burden and saves natural resources and energy. This study is based on partial replacement of fresh natural aggregate with reclaimed aggregate. The project is divided into two phases; first one discusses the mechanical viability of replacing 10%, 20%, 30%, 40%, 50% and 60% of fresh aggregates with reclaimed aggregates. The second phase involves the study conducted on a 9.8 KM dense bituminous macadam (DBM) layer, constructed using the most optimum mix from the first phase of study. Finally, a cost analysis of the pavement was conducted to assess its economic viability. Results In the light of MORTH guidelines, laboratory results showed improvement in the Marshall parameters till 30% replacement of fresh aggregates. Eventually, the DBM layer was constructed using the mix design having 30% replaced fresh aggregates. It showed satisfactory performance after short-term duration without any evidence of rutting or fatigue cracking on surface. Testing of core samples from road stretch proved the negligible degradation with ageing. Conclusion The DBM constructed using reclaimed aggregate showed a saving of 15% in the total cost.