The National Road Research Alliance (NRRA) is hosting “Research Pays Off: Determining Pavement Design Criteria for Recycled Aggregate Base and Large Stone Subbase” on April 20 at 10 a.m. CST, presented by Bora Cetin, Ph.D., Michigan State University and Raul Velasquez, Ph.D., P.E., Minnesota Department of Transportation.
The NRRA’s monthly seminar highlights research topics that will make an impact on the work done here in the state of Minnesota and around the country.
Although recycled pavement materials have been used in roadway base layers for many years, a specific design method does not exist that describes how to build roadways with these materials. Many state Departments of Transportation (DOTs) assume recycled base materials behave similar to base layers built with conventional virgin aggregates (VA). There is a similar lack of an existing design methodology for pavement systems built with a large stone subbase (LSSB).
The proposed project has three main goals. The first goal of the project is to determine the field and laboratory performance of materials and test sections built with recycled aggregate bases (RAB) including recycled concrete aggregate (RCA), recycled asphalt pavement (RAP), and mixtures of these materials with VA. In addition, similar analyses will be conducted for the test sections built with 18 inches thick LSSB with different compaction methods (1-lift and 2-lift), and those 9 inches thick LSSB built with geogrids and geotextiles. To accomplish this goal, the research team will evaluate both the geomechanical and environmental properties of these pavement systems. It should be noted that the LSSB sections have only one type of aggregate base and the multiple recycled aggregate base sections do not have LSSB indicating that experiments for each different design methods are separate. The second goal of the project is to develop a method to estimate the stiffness and permeability of RAB and LSSB designs. This goal will be achieved by establishing correlations between common laboratory test data and both laboratory and field modulus and permeability values. The third goal is to prepare a pavement design and construction specification for roadways built with RAB and LSSB designs. This goal will be accomplished via a summary of the results of all tasks, taking into account the performance, cost benefits, and life cycle costs of these systems. The outcome of this research will optimize the use of recycled materials and LSSB designs, while maintaining pavement quality, resulting in cost savings and conservation of natural resources.
Visit the MnROAD website for webinar connection information.