Louisiana's Experience with Open-Graded Friction Course Mixtures

The Louisiana Department of Transportation and Development (DOTD) began developing open-graded friction course (OGFC) mixtures in the late 1960s and early 1970s. Then, in the late 1980s, a moratorium was imposed on their use because of some early failure issues. However, OGFC mixture performance and service life have improved significantly since a new generation of OGFC mixture was promoted in the United States in the late 1990s. Inspired by the success of other state agencies, the Louisiana DOTD modified the earlier mix design and constructed four new OGFC sections during the past decade to evaluate pavement performance and safety benefits. This paper includes a comprehensive evaluation of Louisiana OGFC mixtures based on their laboratory and field performance. Laboratory work entailed material and mixture design in addition to numerous laboratory tests, namely permeability, draindown, tensile strength ratio, and loaded wheel test. Field evaluation involved visual inspection, pavement condition survey, skid resistance, and traffic safety. With few exceptions in the laboratory, the selected OGFC mixtures showed the potential to meet current Louisiana DOTD specifications, as well as various performance standards established by previous studies. The field analysis indicated that the OGFC test sections showed improved rutting, cracking, and skid performance when compared with typical Superpave^® roadway sections. This performance evaluation will likely support the ongoing use of OGFC mixtures in the state of Louisiana. Additionally, the evaluation provides an opportunity to continually improve the current OGFC specification and mix design procedures adopted by the Louisiana DOTD.