Use of Fine-Graded Asphalt Mixtures

Thin hot mix asphalt (HMA) overlays are more economical than traditional overlays and mitigate problems with curb/gutter height restrictions. Though still more expensive than surface treatments, these mixes should not have chip-loss problems and, because of the fine texture, are relatively quiet. When properly designed and constructed, they may provide a service life comparable to traditional mixes. Another option for thin pavement maintenance is slurry overlay systems. These emulsion- or cement-based materials are spread or sprayed onto the pavement surface at ambient temperatures, do not require compaction, and can be opened to traffic after a short time. This research (1) monitored existing thin overlay performance, (2) developed new thin overlay specifications that districts can easily and cost-effectively implement, (3) worked with districts to construct new thin overlay test sections, and to a lesser extent (4) evaluated various slurry overlay systems in similar applications.