Drainage of Pavement Base Material: Design and Construction Issues

Moisture in pavement base material is a major contributor to pavement failure. Presented is an approach for measuring real-time moisture content in pavement bases during and after rain events. Conceptual models are formed for water flow through pavement sections, and an evaluation of the drainage performance of typical edgedrain configurations is provided. With an extensive sensor network and sophisticated data collection system, the Minnesota Road Research Project (MnROAD) provided an opportunity to study pavement drainage and associated base materials. Understanding the short-term, time-dependent variation in moisture contents allows the systematic evaluation of new and existing edgedrain systems. Two typical drainage configurations constructed at the MnROAD site were chosen for the study. The first section consisted of edgedrains that were introduced into a dense-graded base material to simulate retrofitting of pavements; the second section involved a traditional edgedrain design. Data were collected from an automated weather station and from Time Domain Reflectometry probes. Data collected at the MnROAD site indicated that current edgedrain design and construction techniques may result in pavement drainage systems that are only partially effective in directing flow away from the pavement base.