Lightweight Aggregate Improves Road Surfaces for Cyclists

By Dennis Woolman and Daron Brown, Buildex, Inc.

Douglas County, Kansas, the home of the University of Kansas, maintains approximately 50 miles of mainline asphalt chipseal constructed withCyclists 3/4” x 1/8” coarse Haydite lightweight aggregate on an annual basis. However, due to the coarse texture of the mainline chipseal, a solution was needed to create a smoother surface for the area’s cross-country cyclists. The Douglas County officials decided to continue using the coarser Haydite on the mainline, and applied a 1/8” x 0 graded fine Haydite aggregate chipseal on the road shoulders, which provided the smooth surface that the cyclists needed to meet their riding challenges.

The chipseal on the mainline was applied first at an emulsion shot rate of .37 gallons per square yard. Using the same equipment, both shoulders were then chipsealed with a shot rate of .16 gallons per square yard. The finer chipseal on the shoulders was applied the same day after the mainline chipseal had adequate time to set, typically 1 ½ to 2 hours. Both systems were rolled using a pneumatic rubber tire roller as close behind the chip spreader as possible.

Overall, it has been a win-win situation for everyone with the maintenance of the mainline roadway, preserving the shoulders, and providing a smooth surface for our KU cyclists.

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