Evaluation Of Laboratory Performance Of Sasobit And Zycotherm As An Additives For Warm Mix Asphalt On Performance Characteristic

Abstract

Warm Mix Asphalt (WMA) is a fast emerging green technology which has a potential to replace Hot Mix Asphalt (HMA) and significantly reduces the production temperature of asphalt mixtures through lowering the viscosity of asphalt binders. The technology can reduce production temperatures by as much as 30 percent. Asphalt mixes are generally produced at 150º C or greater temperatures depending mainly on the type of binder used. WMA mixes can be produced at temperatures of about 135ºC or lower.This paper presents the findings of an experimental study aimed at evaluation of Marshall mix design and moisture-induced damage properties of Sasobit and Zycotherm modified WMA mixtures and were compared with HMA mixtures. Marshall mix design and moisture-induced damage properties were evaluated for varying dosage rate of WMA additives (1% to 5% of Sasobit by weight of binder with increment of 1% and 0.05% to 0.2% of Zycotherm by weight of binder with increment of 0.05%). Marshall mix design properties which include bulk specific gravity of compacted mixes (Gmb), air voids (VTM) content, voids filled with mineral aggregates (VMA) and voids filled with asphalt (VFA) were evaluated. Moisture-induced damage was evaluated by the Tensile Strength Ratio (TSR) approach and boiling water test. Test results indicate that WMA mixtures satisfied requirements of mix design properties. Further, WMA mixtures exhibited higher resistance to moisture-induced damage and fulfilled the minimum TSR requirements. In addition, dosage rate of WMA additives had significant effect on both Marshall mix design and moisture-induced damage properties.