- Consistency test ? 2-3 cm
- Cure time ? 2-3 hours
- Wet cohesion ? 30-minute set time (12 kg-cm minimum); 60-minute traffic time (20 kg-cm minimum)
- Excess asphalt ? 50 g/s.f. maximum
- Wet stripping ? pass (90 percent minimum)
- Wet track abrasion loss ? one-hour soak (50 g/s.f. maximum); six-day soak (75 g/s.f. maximum
- Mix time at 77 degrees F ? controllable to 120 seconds minimum
According to Dorman Tompkins, Vance Brothers? project superintendent, the 14-man crew working on the project used a Scan Road (Bergkamp) microsurfacing paver to apply the mixture, which contained a Type III ISSA approved aggregate.
?We used a Joplin Chap lead mining by-product of 3/8-inch to minus 200 aggregate,? Tompkins says. ?We used nurse trucks to supply the rock, emulsion and water, with all the components being properly proportioned and mixed in the paver?s pugmill.?
The spreader box was equipped with two squeegees, one directly at the back of the box to spread the material and the second located 18 inches behind the first squeegee. The second squeegee provides the surface texture.
?It was pretty much straightforward as Cape Seal projects go,? says Tompkins, who?s been with Vance Brothers for 18 years. ?The road is 24 feet wide and expands to 28 feet in the center, and it has 10-foot wide shoulders on one end.
?We pulled the shoulders first and then the 12-foot wide travel lanes,? he explains. ?Our 12-foot-wide spreader box can be expanded hydraulically to 14 feet, so we were able to pull the travel lanes in one pass, even at the widest center part of the road. We also had to treat approximately 75 feet into the access roads in order to achieve good transition onto the main road.?
Even with the emulsifiers used in the mix having a one-hour cure time, Tompkins? crews had the advantage of building the project without worrying about traffic. The U.S. Army Corps of Engineers closed the road to public traffic during construction.
In total, the project required 7,000 linear feet of crack seal repair and over 50,000 square yards of surface treatment. With Vance Brothers supplying its own oil for the chip seal application and manufacturing its own emulsion for the microsurfacing portion of the project, Tompkins says it?s a lot easier to control the staging and quality of the work performed.
?When you don?t have to worry about traffic control, and you?re able to control the supply of the material you need, it makes it a lot easier to deliver a quality project,? Tompkins says. ?The Cape Seal process we used on this road will keep it in good condition for a long time to come.?