Optimum bone ash filler in hot mix asphalt

Abstract

Engineers and scientists are frequently investigating various techniques to enhance the performance of the road pavements. Supplementary materials or additives are being evaluated for use in pavement materials to enhance the performance and quality of the pavement structure, in order to provide a durable, impermeable and safe road surface for the road users. This propelled the research for a replacement of the conventional Stone Dust (SD) with Bone Ash (BA) in Hot Mix Asphalt (HMA). The Optimum Bitumen Content (OBC) was determined for all the sample mixes by Marshall mix design. The SD was replaced with BA in the following order 0% (control), 20%, 40%, 60%, 80% and 100% at OBC of 6%. Laboratory testing and experimental results indicated higher stability value, lower flow value at optimum BA content of 20%. The Void in the Mix (VIM), Voids filled with Bitumen (VFB) all lie well within range thus satisfying the code (NGSRB, 2016) specification. Generally, there was improvement in the Marshall and Mechanical properties of Asphalt concrete mixtures when BA was used. It can be concluded that optimum bone ash content of 20% at optimum bitumen content of 6% is recommended for a good HMA.