Experimental investigation of Bituminous concrete mix using rice husk ash as a mineral filler

Abstract

Fillers when introduced in asphalt concrete helps filling voids thus producing a dense mix. Department of Roads, Nepal in its specification, 2073 identifies cement, stone dust and hydrated lime as fillers. These filler are expensive and are extensively used for secondary purposes. Thus, there is a need of filler which would fulfill the technical requirements as well as be economically cheaper than the existing ones. In this thesis, rice husk ash as mineral filler was used at varying contents (2%, 3% and 4%) with varying bitumen contents (4.5% to 6%, with increment of .5%).Stone dust was used to produce control mix. The prepared samples were tested for different Marshall Properties. Moisture susceptibility of the samples were also tested as per Marshall Immersion Test. Marshall Stability improved significantly, flow values were also within the range. Volumetric properties were also found to be satisfactory. The rice husk ash samples proved to be effective against moisture damage. Thus, rice husk ash can be incorporated in asphalt mix as mineral filler in those areas where such ashes are found abundantly, also solving disposal problems and in turn the environmental problems.