Protocols for Accelerated Pavement Testing of Fully Permeable Pavements

Fully permeable pavements are used as an alternative means of managing stormwater on roads, parking lots, and other paved areas. In the past, they have primarily been used only in areas with very light traffic, and designs have been empirical. With road agencies coming under increasingly stricter stormwater management requirements, there is growing interest in using these types of pavements under heavier traffic loads. A study was therefore initiated by the Interlocking Concrete Pavement Institute (ICPI) and the UCPRC to better understand the behavior of fully permeable pavements and to formalize the design process using a more mechanistic type approach. The study was undertaken in phases and included laboratory testing, modeling, accelerated load testing, development of design procedures, life-cycle cost assessment, and environmental life cycle assessment. Most fully permeable pavements include a subbase/reservoir layer of large (75 mm) railway ballast aggregate, to support the load under wet conditions, and a base of smaller (25 mm) open graded aggregate as an intermediate layer between the large subbase aggregate and the surfacing. The use of this large open-graded aggregate limit the use of the testing protocols, instrumentation (e.g., multi-depth deflectometers), and data analysis procedures traditionally used in accelerated loading tests. Alternative testing protocols ad analysis procedures were therefore developed for the UCPRC study. This paper summarizes the design procedures and protocols developed for accelerated pavement testing of fully permeable pavements and discusses how the results were used to develop a mechanistic empirical design procedure to optimize layer thicknesses.