About the research
Microsurfacing and slurry seals have the potential to change the way we preserve and rehabilitate roadway surfaces. Advances in this technology can lead to the fast resurfacing of roads using mixtures tailored to meet the needs of each individual roadway. Microsurfacing and slurry seals include the use of polymer modified asphalt emulsion specially formulated with a quick, chemical set. In many cases, the new pavement surface can be returned to traffic in 45 minutes or less without the risk of windshield damage from loose aggregates. The mix design formulation still heavily relies on mechanical testing and experience with local materials. This research aims to introduce scientific measurements into the microsurfacing and slurry seal mixture design that can be used to pinpoint the breaking/setting behavior between emulsions and aggregates. Zeta potential is the electro-static repulsion that keeps mixtures suspended for some time. The addition of aggregates change the mixtures’ chemistry and zeta potential. This research plans to scientifically measure and engineer change in zeta potential of the system to enhance the setting and adhesion properties of the mixture. Aggregate fines have the highest surface energy to influence the emulsion’s setting time and thus will dominate the reaction rate and setting characteristics. The zeta potential will be measured in several experimental conditions by means of a Malvern Zetasizer Nano with a titrator. Titration allows for working curves of zeta potential to be developed for changing field conditions. The working curves allow for scientific adjustments to be made to the mix design while accurate setting predictions can be achieved for a variety of conditions. The impact of this work will improve preservation treatments and mixture optimization techniques. The science may someday lead to cold-applied emulsion technologies that can be placed, set, and almost immediately returned to traffic.