BACKGROUND: Pavement preservation provides a means for maintaining and improving the functional condition of an existing highway system. Although pavement preservation is not expected to substantially increase structural capacity, it generally leads to improved pavement performance and longer service life. Slurry seals and scrub seals are frequently used as pavement preservation treatments for flexible pavements. Slurry seals are used to mitigate oxidization and scrub seals are used to seal cracks and prevent moisture intrusion. Tack coats are applied to promote bonding of the preservation treatment to the pavement. Although a great deal of information on the design, materials, and construction practices of these treatments is available, there is no nationally accepted guidance on their construction. There was a need to develop guide construction specifications to help state departments of transportation (state DOTs) apply these treatments more effectively and achieve the most benefit of their application.
OBJECTIVE: The objective of this research was to develop recommended guide specifications for the construction of slurry seals, scrub seals, and tack coats as used in preservation treatments.
Status: Research is complete.
The research reviewed and evaluated the current practices for the construction of slurry seals, scrub seals, and tack coats and proposed (1) a set of proposed guide specifications for their construction and (2) a set of practices for quality assurance of their construction. The final deliverable includes 3 parts: Part !: Final Report, Part II: Proposed Guide Specifications for Construction of Slurry Seals, Scrub Seals, and Tack Coats, and Part III: Proposed Quality Assurance Guide. Parts II and III have been provided the AASHTO Committee on Materials and Pavements for consideration and possible incorporation into the AASHTO Guide Specifications for Highway Construction; they are not available. Part I is available at https://onlinepubs.trb.org/onlinepubs/nchrp/docs/NCHRP14-44_Part-I_FinalReport.pdf