Indiana subdrainage experience and application

The applications of pavement subdrainage in the state of Indiana are Presented. A recent study evaluated pavement subdrainge systems and measured and predicted moisture conditions underneath various types of pavements. Camera systems were used for internal inspection of the edge and geocomposite drains. Pavement instrumentation instrumentation included moisture blocks, pressure transducers, temperature probes, rain and outflow tipping buckets, and a data acquisition system. Ongoing research using a tesst site on I-469 at Fort Wayne, Indiana, is aimed at finding the optimum location and layer configuration in configuration in flexible pavement; it uses those instruments as well as a TDR system, neutron probes, resistivity probe trees, and and enhanced data acquisition process. The research is a long-term project that will build on the data base of material hydraulic characteristics and performance. Indiana Department of Transportation has formed a committee to address issues related to use subdrainage. Some of the recommendations from the committee were tp abandon geocomposite drains, use bigger concrete protector walls at outlet pipes, and implement a routine inspection and maintenance program for drainage systems.