EFFECT OF GRADATION OF AGGREGATES ON MARSHALL PROPERTIES OF SDBC MIX DESIGN

Deepesh Kumar Singh Lodhi, R.K.Yadav

Abstract: Semi Dense Bituminous concrete (SDBC) is the upper bituminous layer of the road subjected to moderate traffic loads. The grading of aggregates used to prepare the SDBC mix should fall within the limits specified in MoRTH. For each aggregate fraction there is a specified gradation range with lower and higher limits of aggregates passing through a particular sieve size. The gradation range specified in MoRTH is quite wide. Therefore mix design by adopting a particular gradation of the aggregate falling within the MoRTH range also affects the Marshall properties. The present study is taken to evaluate the Marshall property of SDBC mix prepared using the aggregate having different grading within the grading limits specified by the MoRTH. In order to study this aspect five mixes having different gradation were prepared. The gradation used correspond to Lower Grade (L.G.), Lower Middle Grade (L.M.G.), Middle Grade (M.G.), Higher Middle Grade (H.M.G.), Higher Grade (H.G.) of the gradation range specified by MoRTH . The test result revealed that there is significant variation in Marshall Properties of the mixes having different gradation of the aggregates. The Stability values obtained is maximum for the Lower Middle Grade (L.M.G.) range of MoRTH specification. The Flow values obtained is maximum for the Middle Grade (M.G.).The Optimum Bitumen Content (O.B.C.) is also minimum in Lower Middle Grade (L.M.G.).

Keywords: Aggregate Gradation, Semi Dense Bitumen Concrete, Marshall Properties, Morth.

DOI: https://doi.org/10.15623/ijret.2016.0502005