Development of High Friction Surface Treatment Prescreening Protocols and an Alternative Friction Application
Thomas Bennert, Robert Blight, Vahid Ganji, Drew Tulanowski, Susan Gresavage
Abstract
The use of high friction surface treatments (HFST) has become increasingly popular to help improve roadway friction properties and reduce the number of lane-departure and breaking-related accidents. Conventional HFST installation consists of applying an epoxy-resin material to an existing roadway surface and “gluing” a hard, highly angular fine aggregate to the roadway surface. When constructed correctly, skid resistance values (SN40) are often measured in the upper 60s and 70s. However, this functional overlay does not come without potential issues. Performance and service life is strongly dependent on the quality of the construction process, as well the quality of the substrate, which is often difficult to assess in situ. The paper summarizes the forensic testing of three HFST installations in New Jersey—one performing well and two showing premature failure. Testing procedures and preliminary criteria for existing asphalt pavement surfaces were developed to address whether or not epoxy-resin HFST is a viable option. Additionally, the paper summarizes the development and forensic testing of a potential alternative to the epoxy-resin based HFST application. This alternative surface, called a high friction chip seal (HFCS), incorporates the same hard, highly angular fine aggregate but using asphalt binder as the “gluing” medium within the chip seal application process. Three different aggregate sources were evaluated using the HFCS application on Rt 68 in New Jersey. Laboratory testing of the aggregates, as well as field measurements of the test sections, were conducted. It was found that HFCS could be a potential alternative for areas where premature HFST failure is a concern.