SEDL / STP / STP1108-EB / STP17823S

Stabilization Mechanisms in Polyolefin-Asphalt Emulsions

Hesp, SA
Ph.D. Student, University of Toronto, Toronto,

Woodhams, RT
Professor of Chemical Engineering, University of Toronto, Toronto,

Pages: 19    Published: Jan 1992

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Abstract

The successful use of polyethylene as a polymeric modifier in asphalt paving materials has encouraged research into development of a product where the polyolefin is emulsified in the hot asphalt medium without being subjected to phase separation. In the last thirty years, patents and publications have given new and old ways of accomplishing the difficult task of achieving an inherently stable mixture.

These polymer-in-asphalt type dispersions suffer from a tendency towards gross phase separation by coalescence and subsequent creaming. It has been reported in a number of feasibility studies that the polymer-asphalt incompatibility, as experienced in polyolefin modified mixtures, translates into a deterioration of ultimate properties. However, in the absence of these detrimental effects, asphalt concrete properties could be enhanced significantly. The possible benefits to our roads as reported in the literature are substantial: increased rutting resistance, low temperature cracking resistance, elevated tensile strength and others.

A condensed review illustrates the various approaches that have been employed for the stabilization of polyolefin dispersions in asphalt binders for paving applications.