To the rescue

Recycling saves money and eliminates steps in road repair

Article May 20, 2004
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Reclamation and recycling has rescued our county,” stated W. Arthur Reeve, P.E., county engineer for the county of Del Norte, Calif. “We wonder now how we ever got along without it.”

For years the county has repaired roads by first chunking up the old asphalt, loading it into dump trucks and hauling it several miles to either the landfill, which is becoming increasingly expensive, or to pits where it will be run through a crusher. Then they hauled back spec aggregate in preparation for the final grade.

“We’ve eliminated all of those steps,” said Reeve. “Like many agencies we’ve been forced to look for cheaper alternatives. We’ve been reading about reclamation and recycling in trade magazines and decided to look into it. It appeared it might eliminate several steps and help us save money. However, we were skeptical if the millings would be reusable. We took the millings from an Asphalt Zipper demonstration to our lab and ran our tests, including a nuclear compaction test. We were pleasantly surprised to find that they came within spec. We eventually purchased an Asphalt Zipper (Circle 911) reclamation attachment that would connect to our loader.”

To date the county has put reclamation and recycling to the test on three public roadways. The first, Hamilton Avenue, consisted of approximately 400 cu yd of existing asphalt. They ground, or “zipped,” the entire roadway in just a couple of hours.

“We had the entire job graded, compacted and ready to pave in one day. This job would have taken us three to four days using our old method,” said Reeve. “The work was done during our peak tourist season, so the faster finish time was greatly appreciated. The other two pretty much followed suit.”
The county’s crews, though skeptical at first, have all readily accepted reclamation and recycling. “It’s a much simpler, more efficient way of doing things,” stated Joe Hoke, road superintendent. “We wouldn’t want to go back to the old method. Why would you when reclamation/recycling is faster, cheaper, more environmentally friendly and produces a better finished product?”

Products

What follows are brief descriptions of a few of the latest products for doing demolition work and recycling and reclaiming roads.

Hot in-place recycling

Specialized in hot in-place recycling of asphalt pavements for roads and highways, Martec Recycling Corp., Vancouver, British Columbia, has developed its Hot-Air Heating and Postheating, Drying and Mixing technology for bringing new life to worn road surfaces. This patented technology that combines the forced hot-air and low-level radiant heating system with a postheating/drying/mixing process has been successfully utilized in manufacturing the AR2000 Super Recycler (Circle 912). Martec’s state-of-the-art AR2000 equipment train recycles all types of asphalt pavements and produces asphalt that is fully compliant with customers’ end-product specifications. The self-propelled, diesel-fueled AR2000 preheats, mills and thoroughly mixes asphalt on site in a continuous, one-lane operation without burning bitumen or fracturing aggregate. Energy- and fuel-efficient, capable of recycling to depths of 50 mm or more with a work speed of 2-6 m/min, AR2000 uses its recirculating hot-air heating system and operates virtually emission-free. Martec’s technology offers potential savings of up to 35% in cost and 50% in time over conventional resurfacing methods. AR2000 is available worldwide under direct sale, lease or partnership agreement.

The right beat

Featuring Krupp percussion technology, the HB 5800 hydraulic breaker attachment from Atlas Copco Construction Tools Inc., West Springfield, Mass., has a service weight of more than 6 ton. The HB 5800 (Circle 913) accepts a hydraulic flow of up to 103 gal/min at 2,610 psi and delivers an impact rate of up to 460 blows per minute. The breaker comes standard with AutoControl, a monitoring system that allows the hammer to adapt its frequency and power output to match operating conditions. It begins by firing the first stroke at half power to create a pilot notch that will center the working tool and prevent unnecessary tool slippage. It then adjusts the power output to match the density of the specified material to be broken. This reduces excess shock on both the hammer and carrier and lengthens the service life of tension bolts and retainer bars.

Remote demolition

It’s not quite the Terminator from the movies, but it is a robot bent on demolition. The Brokk 330 (Circle 914) has incredible power, precision and productivity in a compact package, according to Brokk Inc., Monroe Wash. A 1,212-lb hydraulic breaker fitted to the arm of the 4.2-ton machine delivers a hitting power of 600 ft-lb. Furthering its versatility, the arm can work with a variety of attachments, including crushers, scabblers, shears, grapples and buckets. The 330 is operated by radio remote control from a lightweight, easy-to-operate control box, which allows the operator to work at a safe distance. The standard 30-kw electric power plant can be replaced with a 50-kw, low-emission diesel engine for operation free of electric cables.

Air breakers

The stars of the new line of air tools from Kaeser Compressors Inc., Fredericksburg, Va., are the ergonomic paving breakers. Available in 40-, 60- and 90-lb models (Circle 915), these tools offer reduced fatigue, increased productivity and reduced noise without compromising performance or price. The valves, pistons and other moving parts are made from shock-resistant tool steels and are heat treated to a specified Rockwell hardness for exceptional toughness and durability. Other air tools available are rock drills, rivet busters, trench diggers, chipping hammers and backfill tampers.

Small miller

The W 50 DC (“deep cut”) cold milling machine was introduced by Wirtgen America, Nashville, Tenn., at World of Asphalt 2004 in March and replaces the W 500. The W 50 DC (Circle 916) represents a more productive cutting machine housed in a larger platform than the new W 50, also introduced at World of Asphalt.
For example, the W 50 DC boasts a cut depth of 8.3 in., compared with 6 in. on the W 50; a standard drum diameter of 29.5 in., compared with 23 in. on the W 50; and a Deutz engine of 123 hp, compared with 80 hp in the W 50.

The W 50 DC is a road milling machine with a mechanically driven milling drum and loading conveyor. The spacious and comfortable operator’s platform has ample leg room. The seat is individually adjustable and can be moved sideways beyond the edge of the machine. Maximum safety is provided by its totally clear view of the milled edge.

Wirtgen’s Flexible Cutter System, providing fast change of milling drums in the field, also is available for the W 50 DC in the standard widths of 300, 400 and 500 mm.

Central mixing

A wider rotor, greater cutting depth and a more powerful engine are featured on the MPH122 center-mounted recycler/stabilizer from Bomag Americas Inc., Kewanee, Ill. The MPH122 (Circle 917) features hydrostatic drive of its center-mounted rotor with automatic power adjustment that allows it to stabilize or recycle a variety of materials, including oil and chip surfaces and asphalt roadways.

The MPH122 offers a 92-in.-wide rotor with 194 cutting teeth and a maximum cutting depth of 19.7 in. Cutting teeth are strategically positioned for uniform material pulverizing, sizing and mixing. Pulverized material may be mixed with a binding agent or additional granular material for improved road-base performance. Additionally, the universal rotor design on the MPH122 makes it equally effective at soil stabilization applications.

RAP on deck

Shaker and scalping decks are available from the Ace Group, Surrey, British Columbia, in a variety of sizes from 3 x 5 to 4 x 10 in. Custom stands and screen cloths also are available. The RAPwrangler (Circle 918) is designed to be powerful and easy to maintain. The unit is suitable for stationary, portable, drum or batch plants and comes in several configurations with a choice of a powerful 30-hp or a 50-hp motor. The 20-in. rotor spins at 127 rpm and is equipped with 312 replaceable tungsten-tipped milling teeth that shred football-size chunks down to 1 in. at a rate of 250 ton per hour.

Mobile jaw crusher

Designed for mobile crushing applications such as highway construction, demolition, quarry and excavation work, the BR380JG-1 from Komatsu America Corp., Vernon Hills, Ill., produces high-quality aggregate that is suitable for use or sale. The BR380JG-1 (Circle 919) is equipped with a large-capacity jaw crusher and powered by a 180-hp engine. It has an output capacity of 55-265 tph. Crushing performance is improved with the addition of a load-presetting semiautomatic feeder and increased crusher rotation speed, making the machine ideal for crushing concrete debris, fine crushing natural stone and producing large volumes of aggregate.

Complete recycler

The CIR 1200 is a one-piece full-specification cold in-place recycling machine. The patented design allows for the surface to be cut and planed, the material to be sized and weighed, new material to be added and all material to be mixed uniformly. The CIR-1200 (Circle 920) features an 11-ft 6-in. cutter with optional cutter extensions up to 13 ft 6 in.

Blast away

Blast Designer version 5.0 (Circle 921) from Precision Blasting Services, Montville, Ohio, will allow the quick calculation of burden, spacing, stemming, subdrilling, powder column length, priming, total drill footage and powder load. A diagram of the designed blast will be shown in graphical form on the screen. The software also will determine the powder factor, total weight of explosive per blast and a great deal of other information needed to properly design and conduct blasting operations.

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