MnROAD Capabilities
MnROAD’s two road segments comprise 51 instrumented concrete and asphalt pavement test sections, representing a broad range of materials and designs, that can be utilized for both the study of pavement designs and as a test track for many other activities. Data collected from these test sections enable researchers to:
- Rapidly evaluate the potential performance of new designs and materials under real-life conditions.
- Examine the effects of environmental conditions, traffic loads and volumes, and innovative construction techniques and materials on pavement performance.
- Design customized experiments for both interstate and low-volume roads with the help of experienced MnROAD staff and on-site equipment to support unique researcher needs.
- Perform pavement testing in a completely safe work zone without disrupting the driving public by taking advantage of MnROAD’s unique parallel roadway for traffic diversion.
- Validate current and new pavement design procedures over a broad range of inputs.
In this page:
Mainline Section
The mainline consists of a 3.5-mile interstate roadway carrying “live” traffic. Cell design/layout can be found in Appendix A. The mainline consists of both five-year and 10-year pavement designs. The 5-year cells were completed in 1992 and the 10-year cells were completed in 1993. Originally, a total of 23 cells were constructed, comprising 14 hot-mix asphalt (HMA) cells and nine Portland cement concrete (PCC) test cells. In 1997, two SuperPave HMA test cells and six ultra-thin whitetopping concrete cells were added. Maintenance activities were performed routinely to maintain ride quality and to study different maintenance activities, anticipating that the cells would be reconstructed at a future date.
Traffic on the mainline comes from the traveling public on westbound I-94. Typically the mainline is closed once a month, and traffic is rerouted to the original interstate highway to allow MnROAD researchers to collect data and record test cell performance. Traffic volume on this road segment has increased 40% since the test facility first opened in 1994.
Mainline Equivalent Single Axle Loads (ESALs) are determined from two weigh-in-motion (WIM) devices. The raw data are collected, stored in the MnROAD database, and used to calculate the mainline ESALs; these results are also stored in the database. An IRD hydraulic load scale was installed east of the mainline test cells. In 2000, a Kistler quartz weigh-in-motion scale was installed in the transition between two concrete test cells (Cells 10 and 11). The mainline has received about five million flexible ESALs and 7.8 million rigid ESALs as of December 31, 2003.
Low-Volume Road Section
Parallel and adjacent to the mainline is the Low-Volume Roadway (LVR). The LVR is a two-lane, 2.5-mile closed loop containing 20 test cells. Cell design and layout can be found in Appendix B. Traffic on the LVR is restricted to a MnROAD-operated vehicle—a typical 18-wheel, five-axle tractor/trailer with two different loading configurations. The “heavy” load configuration results in a gross vehicle weight of 102 thousand pounds (102 kips, or 102K configuration). The “legal” load configuration has a gross vehicle weight of 80 kips (80K configuration). On Wednesdays, the tractor/trailer operates in the 102K configuration and travels in the outside lane of the LVR loop. On all other weekdays, the vehicle travels on the inside lane of the LVR loop in the 80K configuration. This results in a similar number of ESALs being delivered to both lanes. ESALs on the LVR are determined by the number of laps (typically 80 per day) for each day, and are entered into the MnROAD database. A number of test cells have been reconstructed on the Low-Volume Roadway.
Instrumentation
Data collection at MnROAD is accomplished with a variety of electronic data collection and storage systems, gathering data from the different types of sensors located in the pavement surface and sub-layers. Originally, the network included 4,572 sensors; since then additional installations and sensor types have been added, as some of the original sensors have deteriorated and failed. Each of these sensors can be linked by fiber optics to MnROAD’s computerized data collection system. Data flows from these sensors to several roadside cabinets and from there to the Mn/DOT Materials Research and Engineering Laboratory in Maplewood, Minnesota for storage and analysis. The sensors measure variables such as temperature, moisture, strain, deflection, and frost depth in the pavement, to name just the basics. Detailed information on sensors and their use can be found on the MnROAD web site under sensors or other related reports.
Database
The MnROAD database is used to archive and retrieve data for researchers throughout the world. It consists of an Oracle database engine that operates on many tables of data. The database manager manages the database and loaders needed for data input. Data requests are processed through the MnROAD research staff and database manager, so researchers requesting data fully understand the data we supply. Sensor data, deflection testing, lab testing, and performance data is available for researchers’ use. For more information on the MnROAD database, please visit the MnROAD Web site or contact any of the MnROAD research staff.