Minnesota Department of Transportation

511 Travel Info

Pavement Design

 

Friction Truck and Trailer

Friction (Skid) Testing

The MnDOT Office of Materials and Road Research operates one Dynatest Pavement Friction Tester. This device measures skid resistance, which is the force that prevents a non-turning (i.e. locked-up) tire from sliding on the pavement’s surface.  Skid resistance is an important parameter because inadequate skid resistance may lead to higher incidences of skid related accidents. It may also be an important parameter when evaluating materials and construction practices.

The device consists of a tow vehicle and a two-wheeled trailer and conforms to ASTM E-274 “Standard Test Method for Skid Resistance of Paved Surfaces Using a Full-Scale Tire” specifications. The MnDOT device has one smooth tire and one ribbed tire and can perform testing with either tire. The device is driven on the road to be tested at a constant velocity of 40 mph. When a test is taken, pumps are activated and spray water in front of the test wheel. Then, the brakes on the test wheel are activated and the horizontal and vertical forces acting on the wheel are measured. This data is then used to calculate the ‘Skid Number’.

 

Request Testing

Skid testing may be performed whenever pavement temperatures are warm enough that the water sprayed during testing won’t freeze and become a hazard.

Please use the following form to file all requests:

Non-Destructive Testing Request (MS Word 39 KB, 1 p)

FWD Calibration Center

The MnDOT FWD Calibration Center is located at the Materials & Road Research Laboratory in Maplewood Map/Directions to Office of Materials. Prior to traveling for calibration, please complete the Calibration Checklist (PDF 54 KB, 1 p).

Address testing requests and questions to:

Greg Larson

Non-Destructive Testing

Greg.C.Larson@state.mn.us
651-366-5404

Test results will be e-mailed to the requester.