Blue Earth County Superpave Level I Project: CSAH #8 from TH 22 to TWP 167

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.