Use of StreetPave for Design of Concrete Pavements for Cities and Counties in Minnesota

The Minnesota Department of Transportation’s (MnDOT) concrete pavement design procedure, RigidPave, is based on the 1981 American Association of State Highway and Transportation Officials (AASHTO) Interim Guide and is entirely empirically-based. The American Cement Pavement Association (ACPA) developed StreetPave based on the Portland Cement Association (PCA) thickness design method with updated information, including a new fatigue model. This study compared RigidPave to StreetPave with a review of the input variables and design inputs used by surrounding departments of transportation. Existing thin (six inches or less) concrete pavements were also evaluated, which included both city and county pavements and test cells at MnROAD. There are two primary differences between the RigidPave and StreetPave: 1) traffic is handled differently and 2) the underlying design methodology. Both are based on time-tested and proven design methodologies and provide generally similar designs. The predicted design lives of the doweled low-volume cells at MnROAD appear to be similar using either StreetPave or RigidPave. The examples provided by cities and counties typically did not contain enough known information, and therefore, required too many assumptions for analysis. The authors recommend that StreetPave be added as an alternate concrete pavement thickness design procedure for city and county projects in Minnesota. Use of the StreetPave is currently allowed by the Virginia Department of Transportation for design of secondary roads. It was also determined that RigidPave has a built-in reliability of approximately 89% due to a factor of safety that is applied to the modulus of rupture. An alternate approach to allowing StreetPave as a design option would be to incorporate the reliability knowledge of RigidPave learned as part of this project.