Scrub Seal Research

The objective of this study is to determine if the scrub seal is more cost effective than microsurfacing, chip seals and the 1" hot mix overlay. Scrub seals were placed at 10 different locations and reviews of each section were made to determine the usefulness of the seal. Most of the scrub seals are very promising although it has been determined they should be limited to areas of less than 7500 ADT. Most of these scrub seals are about 1 year old and we are hoping to get a life span of 3 to 4 years from them.

Recently, use of pavement preservation technologies, such as bituminous seal treatments, has increased. Seal treatments are often used to rejuvenate aged asphalt pavements and can decrease permeability and retard oxidation, cracking, and raveling. Many factors affect rejuvenation, and current specifications governing how rejuvenation is characterized could be enhanced. Viscosity testing of asphalt binder extracted and recovered from a pavement’s near surface is the predominant means of characterizing rejuvenation (e.g., a product must reduce viscosity by 40% to be classified as a rejuvenator).  This paper presents data that suggest other rejuvenation approaches are worth considering because (a) extraction and recovery can adversely affect viscosity results, (b) viscosity testing cannot be conducted without forced and unrealistic blending of aged binder and rejuvenator, (c) high test temperatures may not be the most informative for distresses of interest (e.g., cracking), and (d) viscosity could not detect rejuvenation behaviors of some proprietary products.