Microsurfacing mixtures are made of high-quality aggregate and asphalt emulsion components. They are produced at the project site by a mobile microsurfacing machine that mixes and places the product. Normal micro-surface designs contain approximately 13.5% emulsion and include a performance grade (PG) 64-22 asphalt cement (AC). This study investigates the field performance of softer-AC flexible slurry surfacing mixtures used for preparation and surface courses. A PG 48-34 AC was chosen for flexible slurry–microsurfacing mixtures constructed on four test cells at the Minnesota Road Research Project low-volume road facility near Albertville, Minnesota, in September 2005. This AC was used to produce mixtures for both surface preparation and wear courses. The mixtures used a reduced emulsion percentage for rut filling and an increased emulsion percentage for normal leveling courses. A single surface course mixture with the increased emulsion level was placed over the entire project. Pre- and postconstruction evaluations of cracking, rutting, and smoothness were performed. These evaluations were repeated at 6 months, following one winter of service. At 6 months an overall 71% of transverse cracking had reflected through the microsurface. Reflected distress from longitudinal cracks and patched areas was negligible. The rutting condition at 7 months was found to be similar to that at postconstruction, in which an overall 20% decrease was attributed to microsurfacing. Smoothness was favorably affected by microsurfacing construction. International roughness index values were correlated to the amount of material placed in the surface preparation course.
Flexible Slurry–Microsurfacing System for Overlay Preparation
Construction and Seasonal Monitoring at Minnesota Road Research Project
Transportation Research Record: Journal of the Transportation Research Board
Transportation Research Record: Journal of the Transportation Research Board ; 1989-2 , 1 ; 321-326
2007-01-01
Article (Journal)
Electronic Resource
English
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