"Then you have the components within the drums, like breaker bars, that will assist the gradation. Some machines have more actual cutter bits than other machines," Edwards explains. "With the older machines that we use mostly for soil stabilization ? the prequel to the reclaimers ? they didn't have as many teeth." As technology continues to improve ? with increased drum speeds and breaker bars ? the machines are better able to achieve gradation.
Reclaimers/stabilizers also come with two types of cutter housings: fixed and variable chamber.
Terex is one of the manufacturers offering both types. "The fixed housing gives us better first-pass gradation with maximum forward speed of the machine," asserts Jim Holland, Jr., product manager, Terex Roadbuilding. The variable chamber machine is an advantage when performing soil stabilization in "gummy" soils. "The advantage of the variable chamber is that the volume changes at the top. As that material gums up, you can hold it in the top of the housing and material can pass out of there."
Power and performance
When it comes to sizing a reclaimer/stabilizer, power is everything. "Typically, when you size a machine, you need to be looking at your depth of treatment," says Holland. "Obviously, the higher horsepower machines are going to work better in the deeper asphalts. You are going to get more production, more miles per day out of a high-horsepower machine."
This has proven the case for Valentine Resurfacing. "Because we pulverize a lot of deep asphalt ? 6-in.-plus depth ? one of the primary considerations for us is horsepower to get through that thick of material," says Valentine.
As always, there is a trade-off. "Typically, when you have the higher horsepower, you are going to have more torque, more travel speed and more hydraulic horsepower to mix the material better," says Dave Dennison, product manager - soil products, BOMAG Americas. But that excess power does come at a cost. "As you go to the higher horsepower, especially nowadays, you typically require more fuel usage."
You must balance the ability to accomplish the job with the cost of operation and productivity. "The smaller machines are limited in their width and also their depth of cut," says Dennison. "Essentially, if the job has 12 in. of asphalt on it and your depth of cut is only 10 in., you will not be able to use that machine on the job."
With a larger fleet, it is worth considering several different size machines. "We are to the point now where we have enough machines that we can actually make the machine fit an application," says Johnson. "When we first started, all we could have is high-horsepower units because a machine might be doing a light job, a heavy job, a light job and a heavy job. Now, we try to schedule around [the project requirements], because I don't need an 800-hp machine to do a small parking lot when 600 hp will do it."