Effect of Binary Surfactant Mixtures on the Stability of Asphalt Emulsions

Abstract

The interfacial tension (IFT) of different asphalt components (aromatics, waxes, resins and asphaltenes) as 10% solutions in kerosene against different surfactant solution systems has been measured. The data revealed that both asphaltenes and waxes increased the IFT while aromatics and resins decreased it. The former two components are believed to destabilize asphalt emulsions, on the other hand, the latter two components facilitate asphalt emulsion formation and stability. A correlation between the rheological properties of the prepared asphalt emulsions by different binary and single surfactants mixtures and the stability of the emulsion was investigated. The flow curves of the different emulsion formulations clarified that the rheograms were found to attain plastic properties. The yield values, τB and plastic, and apparent viscosities, ξpl and ξapp respectively, were determined from these plots. The results showed that the enhancement of the rheological properties of the asphalt emulsions using different binary surfactant systems were in the following order: dodecyl benzene sulfonic acid sodium salt (DDBS-Na)/decyl phenol ethoxylate e.o.= 15 (DPE-15)>1,1′ (lauryl amido)-propyl ammonium chloride (LAPAC)/DPE-15>DPE-15>DDBS-Na>LAPAC. On the other hand, the order of emulsion stability is as follows: LAPAC>DDBS-Na/DPE-15>DPE-15>DDBS-Na. The effect of the aqueous phase salinity up to 5% NaCl concentration on the stability of asphalt emulsions stabilized by different surfactant solutions systems is discussed. © 1997 SCI.