Influences of Curing Time on Polymer-Modified Emulsion Used for Slurry Seal and Micro-Surfacing Mixes

In Korea 97.6% of a total length in national highway system is paved. Particularly, most of national highway has been paved as asphalt pavement. Surface treatments are recommended to use in distressed asphalt pavements in national highway due to cost-effective, extension of pavement life, and improvement of surface performance such as friction and noise. By applying a cost-effective surface treatment at the right time, the pavement is restored almost to its original condition. Most of government agencies state that surface treatments are the most effective use of limited budgetary dollars to maintain roadway serviceability. Recently, polymer-modified emulsion is being used to improve the stability of surface treatment mixes. However, it is sensitive to curing time and content. In this study, influences of curing time and content on two types of polymer-modified emulsion used for microsurfacing and slurry seal mixes are evaluated using a load wheel tester (LWT) that is a traffic simulating device. It exhibits the approximate compacting effort of 1 million vehicle passes in less than 25 minutes when loaded with 125 lb (56.7kg) of lead shot weight in the laboratory. Based on the LWT test results, the compactability and stability of microsurfacing and slurry seal mixes using polymer-modified emulsions significantly increase as curing time increases. Two polymer-modified emulsions used in microsurfacing and slurry seal mixes show superior performance compared to a conventional emulsion. It can be postulated that polymer-modified emulsions would be more flexible with less bleeding.