In 1996, Blue Earth County paved a rural, two-lane County State Aid Highway using Finn Road or Oil Gravel technology to explore its potential for providing an economical easy to maintain, and improved all-weather driving surface for the County’s 300 miles of gravel road.
Koch Oil designed the mix, and Loveall Construction of Winnebago, Minn., constructed the mix, with construction inspection and contract administration by Blue Earth County. Separate pay items for gravel, quartzite, asphalt, and produce and lay gave the County the flexibility to modify the mix design based on design information and to conduct construction tests for the highest quality pavement. High Float Emulsion 3010 asphalt binder was used. The pavement was constructed in two demonstration sections: one with 100 percent quartzite and one with 50 percent gravel and
50 percent quartzite.
Significant segregation of the mix occurred during construction, which was repaired by spray injection and seal coating. The County reports performance after one winter as good, with initial construction cost about 33 percent less than a traditional 7-ton hot mix bituminous pavement design. No maintenance experience is available to date.
Superpave" technology was developed under the Strategic Highway Research (SHRP) to provide superior performing pavements. In 1996, Blue Earth County paved a newly graded, two-lane County State Aid Highway using this technology. The County wanted to explore Superpave's potential in offering a higher quality, more durable pavement with lower life cycle costs.
MTE of Onalaska, Wis., designed the mix and Loveall Construction of Winnebago, Minn., constructed the mix, with construction inspection and contract administration by Blue Earth County. The aggregate structure was on the coarse side of the maximum density line. Separate pay items for gravel, quartzite, asphalt, and produce and lay allowed the County to modify the mix design based on design and to gain construction information for the highest quality pavement. PG 52-34 binder was used. Aggregate was about 45 percent gravel and 55 percent crushed, coarse quartzite.
The constructability and performance to date have been excellent. Initial construction cost was about 18 percent higher than the County's traditional, fine mix designs. Total pavement structure costs, including aggregate base and pavement, ran about 9 percent higher. The County will continue to monitor the relatively open texture and tendency of the pavement to weep at isolated locations after rains for potential problems.
