India is one of the countries having the largest road network where majority of the roads are paved with bitumen-based macadamized roads with a thin bituminous surfacing or a premix carpet as a wearing course. Bituminous roads are mainly composed of naturally available aggregates and hot bitumen/asphalt, where aggregate makes up 90-95 percent by weight of Hot Mix Asphalt (HMA). Among the various type of bituminous paving mixes in India, Bituminous Concrete (BC) mix having dense grading specification (as per Ministry of Road Transport and Highways (MoRTH))has been used as a wearing course in a pavement structure to distribute stresses caused by heavily trafficked loading and to protect underlying unbound layers from the effects of water. The present study was taken up with the objective of evaluating the properties of HMA mixtures designed using bituminous concrete (BC) and gradation of aggregate. For the preparation of bituminous mixes, three aggregate gradation limits (upper limit, mid-point range and lower limit) for both BC grading 1 and 2 were used and evaluation is done by using Marshall Method of mix design. By evaluating the volumetric and Marshall Properties of the bituminous mixes with different gradations, however in both the grading specifications, value of void filled with bitumen (VFB) is in the marginal range for upper and lower limit gradation and the value of voids filled with asphalt (VFA) is above the specified minimum value and the overall result shows satisfactory performance with the variation in aggregate gradation limits....
Authors: Samiksha shukla, Sandeep shrivastav.