Nontraditional Fog Seals for Asphalt Pavement: Performance on Shoulder Sections in Minnesota

The pavement engineering community has recently been introduced to a number of nontraditional products intended for uses as surface sealers for bituminous pavements. Many new products use agricultural-based components and little is known regarding their effect on bituminous pavement performance. Several nontraditional and "bio-based" fog sealants were applied to bituminous shoulder sections less than two years old. A field evaluation was performed over a three-year period; and included documenting installation; application rates; equipment types; locations; and sampling of the product. Annual field reviews were performed; including tests of pavement marking reflectivity; friction; cracking; appearance; and permeability. Application rates varied from 0.015 to 0.10 gallons per square yard according to the product used. It was found that during the evaluation period; the applications provided various levels of waterproofing; and some test sections experienced less thermal cracking than the control. Nontraditional product applications did not adversely affect the long-term visibility of pavement markings or the overall pavement performance. Laboratory testing of pavement cores showed similar high- and low-temperature performance relative to the control.