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 & 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 & 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 13mm as per MORTH specifications. The present study has been taken to evaluate the Marshal property of both Bituminous concrete (Dense graded) & 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 & aggregates of specified sizes as per IS standards and results are tabulated. There is a considerable variation of OBC in both open & 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.