Effect of emulsifier on physical properties of cup lump modified emulsified bitumen residues

Abstract

The improvement of physical properties of emulsified bitumen residues is the prime concern for researchers to improve the performance of cold mix asphalt and different types of polymers are incorporated in emulsified bitumen for this purpose. However, the bitumen emulsion is usually prepared with the help of emulsifier and the function of emulsifier in the emulsions is to reduce the interfacial tension on the surfaces of bitumen and water droplets which results in a stable droplets suspension system for a sufficient period of time. Despite using it as an emulsifying agent, the impact of emulsifier on physical and rheological properties of bitumen emulsion's residues is never studied before. In this study, different types of bitumen with pen 80/100, 60/70 and Cup lump rubber (CLR) modified bitumen were emulsified at 0.5%, 1% and 6.5% emulsifier (Redicote-EM44) content respectively. Physical tests such as penetration, softening point and viscosity were carried out on bitumen residues to investigate the effect of emulsifier. The results indicate that the emulsifier enhances the physical properties of bitumen emulsion residues. The resistance to penetration was improved up to 20% and 16% for the bitumen emulsion residues of 80/100 and 60/70 respectively while it had adverse effect on penetration value of CLR residue resulting in a decreased performance up to 19%. The effect of emulsifier on softening point was not remarkable but has improved SPV of 80/100 and 60/70 bitumen residues whereas the values decreased for CLR bitumen residue. The viscosity results were with better agreement of penetration and softening point results.