Technology Spotlight: Linear crushers

These non-traditional portable plants produce aggregate from recycled road material – on the fly.

Portable rock crushers are often used to provide the material needed to maintain primary roads because they have large production capabilities and they’re able to meet Department of Transportation (DOT) requirements. These same crushers are also options to provide material for secondary and tertiary roads, as well as roads that do not require DOT-spec gravel.

But considering costs are a driver of nearly every business decision, road contractors likely seek alternatives that can help them win bids and boost their bottom lines. One such alternative on the market is linear crushers, a technology Roadtech Inc. is touting as a means to achieve an average cost savings of between 200 and 400 percent compared with traditional portable plants.

Linear crushers move along a road that is being repaired, crushing existing oversize material along the way. The result is typically mixed with existing gravel and soil that resurfaces the road and generally improves its subgrade at a lesser cost.

According to Ryan Clark, a production engineer at Roadtech, the cost differences for linear crusher users is directly linked to the equipment’s ability to overcome some of the challenges portable rock crushers typically face. “Immediate costs that are eliminated are pit development, pit permitting and material transportation,” Clark says. “Benefits that aren’t directly seen in upfront costs are improved drainage, improved maintainability and reduced environmental impact.”

Limitations

Linear crushers do, however, have some restrictions. They cannot meet DOT-spec requirements because they do not include a screening plant, Clark adds. No screening system has been developed for the Roadtech equipment to date, either, but he contends linear-crusher materials regularly meet or exceed DOT-spec products on a performance basis. The produced material as is cannot, however, be verified before it is immediately placed back onto a road.

“We have a strong belief that linear crushers raise the bar on the standard of work possible on many secondary and tertiary roads,” Clark says. “It is just a matter of getting the word out.” If word does get out, a road-resurfacing renaissance is unlikely because the technology still has limitations in production capacity and in meeting DOT-spec requirements. Plus, the technology has been around for nearly a decade.

Still, Clark says the technology is a relatively untapped one.

Cost savings

“Currently, only progressive thinkers seem to have a strong interest in linear crushers,” he says. “When these individuals come across the technology, there is almost an immediate effort to take advantage of what the technology provides. For the majority, it almost seems too good to be true.”

“Many secondary and particularly tertiary roads do not have developed operating rock pits and quarries significantly close by,” he says. “By overcoming the challenges of traditional portable crushers, linear crushers provide a more cost-effective solution for road resurfacing and maintenance, while at the same time providing the opportunity to improve the road’s standard.”