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.

The objective of this study is to develop performance-related pay adjustment (PA) for in-place air void of asphalt pavements using pavement management data and life-cycle cost analysis (LCCA). In-place air void data were collected from quality assurance (QA) records for a large number of projects constructed in New Jersey from 1995 to 2005. Pavement condition index data were extracted from pavement management database for the pavement sections where air void data were available. Empirical pavement performance models were developed with sigmoidal functions and used to predict pavement service life. An exponential model form was used to relate the expected pavement service life to the quality measures of in-place air voids. After the rationality of the model was checked, LCCA was performed to derive the PA using different analysis periods and maintenance strategies. Monte Carlo simulations were conducted to capture the variation of PA due to the uncertainty of overlay service life. The PA could be significantly affected by the maintenance strategy if it is estimated using the short analysis period with single overlay, while the PA calculated using the infinite analysis period provides a conservative boundary that is not sensitive to the maintenance strategy. The developed LCCA framework provides the flexibility of determining the PA based on state agencies' practice on QA and pavement maintenance.

Preface n the past several years, there have been a number of significant advances in asphalt materials and construction techniques for increasing the durability of pavements. This e-circular contains papers based on a Sunday workshop at the 92nd Annual Meeting of the Transportation Research Board in Washington, D.C., on enhancing the durability of asphalt pavements. The workshop focused on new design and construction approaches for extending pavement life while also improving their sustainability. The workshop also addressed the use of new materials, methods of mix analysis and cracking models, coupled with specific construction techniques that can significantly increase the life of the asphalt pavement. Furthermore, it covers actual application of these materials and approaches and some associated long-term benefits. The most significant outcome of this workshop was to show that these materials and approaches are readily available in the marketplace today and only require some relatively minor changes to specifications.-Frank Fee Frank Fee, LLC