The load carrying capacity of Trunk highways in Minnesota have been evaluated by the Minnesota Department of Highways using a plate bearing test procedure for about 16 years. In recent years, many counties and municipalities have been interested in road strength information on their roads and streets to assist in establishing spring load restrictions, and to some extent to evaluate their design strengths. The plate bearing test equipment requires the use of a special trailer for a load reaction; the total cost of this equipment is such that it is not economically feasible for the individual counties to acquire such equipment.
Experimental concrete pavement containing variations in joint spacing, reinforcement, dowel sections, and joint fillers were used on Minnesota T.H. 36 to determine optimum design. Surface rating, South Dakota Profile Surface Rating (PSR), and Concrete Pavement Evaluation System (COPES) studies were performed to evaluate the pavements. The best sections were the 15 foot and 20 foot sections with bituminous coated or rust inhibitor painted dowels. The longer sections, 33 foot and 65 foot, and the panels with sleeved dowels performed poorly. All joint fillers failed within three years.
TH 28 road pavement structure is a conventional AC road, which has previously been widened using mixed soils. Today the road has several differential frost heave problem sites at different road sections. The purpose of the GPR survey in the TH 28 was to detect base and subgrade problem areas and to find reasons for them.
