Effect of High RAP Content on Marshal Performance of Hot Asphalt Mixture for Surface and Binder Layers

Recently, the exhaustion of new aggregates and rising price " raw materials" have caused increasing exploitation "reclaimed asphalt pavement "(RAP) in construction rehabilitation. It is being reported that usage RAP does not only reduce cost projects due to less consumption aggregate but also saves land resources greatly protects environment, Where same materials used original highway system can be reused rebuild, repair maintain it. appropriate, recycled Aggregates other make a good economy; the" environmental engineering' sense, with supply limited demand increasing, HMA producers begun use "Reclaimed Asphalt Pavement" (RAP) as value component HMA." For this reason, there renewed interest amount hot mix (HMA). Although many factors affect paving, two main are "Economic savings Environmental benefits." useful alternative materials. reduces virgin "virgin binder required productions, study highlight how impacts economic terms through different percentages (10, 15, 20, 25%) from total weight mixture for surface layer, change (30, 40, 50, 60%) layer "HMA-RAP" composition was heated at temperature “150°C” then mixed “170-180°C” plus “153°C” so mixing temperature, obtained “148- 153 ° C" obtain ideal recovery reclamation, where restored rheological properties considered point binder. The results ratios showed large could both layers exceed (20%) (50%) bond layer. This because Marshall stability highest possible during these ratios. As or decreasing ratios, it led decrease stability. test increase asphalt, optimum level (OAC) included decreased percentage reduced (4.9 3.92%) When adding 20% RAP, (4.6 2.3%) This, turn, leads which mixture, influence water, changes bonds between (asphalt aggregate) material still good.