PERFORMANCE EVALUATION OF DENSE BITUMINOUS MACADAM MIX - A REFUSAL DENSITY APPROACH

Nitinprasad R, M.S.Nagakumar

Abstract: Secondary compaction is a state; where the pavement which is compacted with the conventional compaction has been further compacted due to the movement of traffic and which corresponds to the ultimate density which can be attained on the bituminous pavement called as “Refusal density” of the pavement. Secondary compaction has to be studied in detail and it is understood that the 75 blows of the Marshall test does not determine the actual field circumstances. The Marshall design actually in the field will not simulate the field conditions hence there will be a reduction in the air voids at the refusal density. Then due to fineness of the mix, this causes the plastic deformation on the pavement surfaces. Hence an attempt has been made to study the air void content at refusal density. Also the Bulk Density, Air voids (Va), Voids in mineral aggregate (VMA),Voids filled with Bitumen (VFB) of the mix at the refusal density are also studied. For the simulation of the field density in the laboratory a Hugo hammer is used. The usage of the Polymer Modified Bitumen reduces the plastic deformation and other distresses of the pavemen

Keywords: Dense bituminous macadam (DBM), Refusal density, Hugo hammers

DOI: https://doi.org/10.15623/ijret.2013.0213036