Use of Carbonized Rice Husk and Bio-char as Binder Modifiers in Hot Mix Asphalt

Carbonized rice husk (CRH) and biochar (BC) were investigated as partial asphalt binder replacements. TCR and BC modified asphalt binders were initially evaluated with reference to their penetration index and then by volumetric properties, Marshall properties, indirect tensile strength, and moisture damage resistance of HMA made using a modified asphalt binder. Both BC and CRH modifications improved the high-temperature performance of the asphalt binder while reducing the actual asphalt binder required for the optimum HMA. A maximum of 13.75% reduction in actual binder requirement was observed. Although both modifications decreased the Marshall stability and Indirect tensile strength, at most of the modification levels the reductions were small. Marshall stability and Indirect tensile strength values were above the Asphalt institute specifications stipulated for heavy traffic (ESAL>106 for 20 years) highways. All modifications retained more than 80% of their Marshall stability and Indirect tensile strength when subjected to moisture conditioning.