Comparison of Flexible (Dense graded) and Porous (Open graded) asphalt surface course with stone dust as a filler in Marshal Mix design

ABSTRACT Bituminous concrete is the surface layer which will be laid to ply the vehicles above it and to transfer the vehicular wheel loads effectively without undergoing any major deformations. The grading of aggregates for bituminous concrete used for the analysis is as per MORTH and gap/open graded for porous asphalt as per NAPA specifications, the analysis done for dense graded asphalt is grade 2 where the nominal size of the aggregates is less than 25mm as per MORTH specifications. The present study has been taken to evaluate the Marshal property of both Bituminous concrete (Dense graded) and Porous (open/gap graded) asphalt, the tests revealed that there is a significant variation of Optimum binder content for dense graded mix when compared to porous (gap/graded) asphalt surface course. Preliminary tests have been carried out for bitumen and aggregates of specified sizes as per IS standards and results are tabulated. There is a considerable variation of OBC in both open and dense graded mixes where optimum bitumen content is more in dense graded mix when compared to open graded mixes whereas the flow values for open graded mix is more when compared to close graded mixes. Keywords: Flexible pavement, Porous asphalt, storm water, Wearing course, Stability.