THE INTRODUCTION of REFUSAL DENSITY TEST on ASPHALT MIXTURE DESIGN
This paper describes the importance of Refusal Density to achieve Air Voids in avoiding the plastic deformation. Marshall Mix Design procedure requires a VIM value of more than 3%. The final in-situ density may actually be 3% or even 4% higher than the 75 blows of Marshall density. This means that 3% or 4% of air void was reduced during service caused by compaction of traffic. If the original design was for 4% or 5%, the residual value of VIM had dropped down to 1% or 2%, and the road pavement became vulnerable against plastic deformation.. The extensive studies done in four road sections in Java Island of Indonesia related to cracking and plastic deformation in connection with air voids condition after trafficking showed that no plastic deformation were occurred with air void higher than 3%. It is therefore recommended that compaction to refusal density should be introduced to provide a reference density used to ensure that an asphalt mix can be designed so that VIM value would not be reduced to less than 3% during the service life.