MEZATIO ZEBAZE MICKEL - SADRACK  
 
STUDY ON MIXTURE DESIGN AND MECHANICAL PERFORMANCE OF WARM MIX ASPHALT CONTAINING RECLAIMED ASPHALT PAVEMENT

Osamu TAKAHASHI

Asphalt wastes are categorized as industrial waste. They are recycled worldwide in the form of reclaimed asphalt pavement (RAP) for economic and environmental protection purposes. 
From this perspective, developed countries have introduced warm mix asphalts (WMA) mixtures using the medium temperature technology, namely the use of Sasobit to reduce the production and construction temperatures of hot mix asphalt (HMA) mixtures by 20 to 40 °C. 
It is generally known that the lower the manufacturing temperature and the higher the amount of RAP, the lower the physical performance of the mixture. However, the relationship between appropriate formulation and basic physical performance of WMA containing RAP based on the Japanese performance requirements has not been fully cleared yet. 
The present research investigated the relationship by changing the RAP content in the Japanese dense-graded asphalt concrete of 20 mm maximum gradation size with straight asphalt binder of grade 60/80 and checking its effect on the performance of the WMA mixture including Sasobit as additive. 
The results were then compared to that of its equivalent HMA mixture.The optimum asphalt content (OAC) was determined by the Japanese Marshall design method. Evaluation samples with 0%, 10%, 20%, 30%, 40%, 50% and 60% of RAP content were produced. 
These samples were tested for basic physical performances, namely cracking resistance and rutting resistance. As results, WMA mixtures were slightly inferior to the plain HMA mixtures in both performances because the binder consistency decreased. RAP content, over 50%, decreases strain at failure for the WMA mixtures.