"Street sweepers are not designed to pick up the volume of rock that is left on the road," Turner says. "In some cases, with the MK-1 Transfer Sweeper, we pick up about 15% to 20% of what we laid down." In years prior, that 15% to 20% would have been swept off to the side and wasted. But the MK-1 is designed to sweep up all the loose rock, resulting in approximately 20 tons of recycled rock per mile, Turner says.
The MK-1's rotary broom sweeps up the rock onto a conveyor belt which then carries it into the back of a dump truck in front of the sweeper, Turner says. "If you sweep fairly soon after doing the chip seal, we find there's very little contamination in the rock. Leaves and debris gets onto the road; but, barring any inclement weather, if you do it within a day or two it's relatively clean and can be reused," Turner says.
The recycled aggregate can then be stockpiled and used for chip sealing other roadways. When using the recycled aggregate, Turner suggests wetting down the rock before reuse to ensure there is no dust on it. Dusty rocks may not stick to the asphalt when chip sealing.
The MK-1 is an 8-ft.-wide unit, so a 24-ft.-wide road can be done in just three passes, Turner says. "I would say you can safely sweep up two to three miles a day with this sweeper," Turner says.
The ability to recycle aggregate goes beyond saving money. Drivers benefit, too. Loose rock on roads can get kicked up and crack windshields. It is also a danger to speeding vehicles. Hitting loose rock at high speeds can cause a driver to lose control and result in an accident.
For Southwest Surfacing and Quay County, technology and recycling equipment was the solution that offered the most benefit to Turner's company's process, the customer's bottom line, and the safety of motorists traveling on the chip sealed roads.