The AggreScreed can lay up to 18,000 tons of gravel per day at a depth of 0 to 15 in. and crowns up to 3.5%.
With the AggreScreed, the crown is built into a single, full-width pass.
Myron Mullett (right) originally developed the AggreScreed for Mullett Excavating's grading operations. He has since enlisted Tim Lorenzen (left) to help him market the attachment to other end users.
Growing up around a family-owned excavating business, Myron Mullett was practically born to be a contractor. "My brother and I would help my father beginning around 10 or 11 years old," he recalls. "By the time I was 13 or 14, I was an accomplished equipment operator."
After moving to Westcliffe, CO, in 1991, Mullett first began doing excavation work through a local business, then quickly struck out on his own. He started out doing various jobs here and there, but eventually grew the company to $4 million in annual contracts and 20 full-time employees. Mullett Excavating now handles primarily government contracts on five military bases along Colorado's Front Range.
In 2004, Mullett Excavating was working on a government contract job that required laying 90 miles of gravel. "In order to meet the tolerance they gave me, I would have to drive three rows of stakes for all of that distance," he recalls.
Thinking there must be a better way to do it, he began to explore the possibility of designing a blade that would precisely maintain gravel without the need for stakes. "I asked people in the industry what they thought of the idea and they kept bringing up why it wouldn't work," he notes. "So I tried an inexpensive prototype, and it worked better than we ever thought it would."
That was five years and three prototypes ago. Now, the TerraTec AggreScreed is changing the way roads are built. "Today, in spreading gravel, companies use a blue-top staking system," says Mullett, who also serves as TerraTec Industries' CEOut. "To use the AggreScreed, you don't have to place any type of gravel staking in order to accomplish the proper thickness. The [attachment] will ensure that with minute details. The biggest change is that it's a stakeless process."
Attachable to most dozers (125- to 250-hp size recommended), the 16-ft. blade adjusts to 24 ft. in 2-ft. increments. It is capable of laying gravel at any depth from 0 to 15 in. and can even create up to a 3.5% crown in a single pass.
The potential savings can add up quickly. For example, assume a surveyor using two men to lay three rows of stakes every 40 ft. would take about three days per mile to complete; eliminating that process would save roughly $3,120 per mile. It also normally takes at least two passes to achieve a crown. With the AggreScreed, the crown is built into a single, full-width pass, eliminating even more time. If you assume a road measuring up to 24 ft. wide needs to be graded to a depth of 6 in., eliminating passes for the crown and any required re-grooming could save an estimated additional $4,500 per mile.
That doesn't include the savings in material costs. Due to its accuracy, the attachment eliminates typical overages figured into jobs to ensure proper depth throughout, Mullett asserts. So in laying 7,000 tons per mile at $14 per ton - and eliminating a minimum 5% overage - the AggreScreed saves $4,900 per miles.
While every job varies, Mullett and Tim Lorenzen, TerraTec COO, believe such figures are conservative. "There is so much waste currently because of the penalties for being under spec of material thickness that most companies go over and lose material," Lorenzen explains. "The AggreScreed is so accurate, it makes it easier to estimate your job costs and protect your margin."
With a projected cost of $65,000, the attachment "is basically paid for in less than 10 miles of laying gravel road," Lorenzen states. "It doesn't tie up a dozer for the whole day either, so you can fully utilize the dozer and the operator. You can attach and detach this blade in approximately 15 to 20 minutes.
"The AggreScreed lives up to its name," he adds. "It performs like a screed. And it takes variables, like operator experience, out of the mix. The slope is perfect and there are no dips."
For more information and to see a video of the AggreScreed in action, visit www.terratecind.com.
AggreScreed Quick Facts
Height/Width: 4 ft. high by 16 to 24 ft. wide (extends in 2-ft. increments)
Weight: 6,000 lbs.
Capabilities: Lays up to 18,000 tons of gravel per day at a depth of 0 to 15 in. and crowns up to 3.5%
Equipment requirements: Attaches/detaches to any straight-blade dozer (125 to 250 hp recommended) in about 30 minutes
Transport: Can be hauled on any 18-ft.+ equipment trailer