During this past season on the project, Williams Charles rented an Astec ProSizer 2612V fractionating system to process its own FRAP content. The closed-circuit mobile plant incorporates a double-deck PEP Vari-Vibe high frequency screen with a horizontal shaft impactor crusher.
"Even though it allowed us to increase the RAP content of the mixes designs we produced for the project, material specifications prevented us from using about a third of the material that the fractionating process produces," Kutz says.
"Fractionating does separate the material components into more precise sizes, but the Tollway had specific requirements that limited the material sizes we were allowed to use in the mixes to construct the new roadway," he explains. "So, from that aspect, fractionating did limit 100% usage of a RAP stockpile. But customers like the Tollway are moving toward FRAP as a way to save money and be more environmentally conscious."
In general, however, Kutz, who's been with Williams Charles for the past 20 years, says increasing RAP content in asphalt mix designs has been very positive for the company, its customers, and the environment.
"We're saving natural aggregates and we're saving liquid asphalt binder, and that benefits everyone," he notes. "It helps us to remain competitive and it helps reduce the amount of virgin aggregate we pull out of our quarries. That definitely makes recycling old asphalt pavements a winning proposition for us, our customers and taxpayers who pay for new roads and want a minimal impact on their environment."
Whether you invest and operate a basic crusher/screen system or a more sophisticated fractionating system, the bottom line is increasing RAP to lower your operating costs while providing customers with a lower-cost, high-quality mix.
Increasing material costs will continue to challenge asphalt producers/contractors and their customers. Investing in crushing/screening equipment benefits both and also makes both better environmental stewards by recycling existing asphalt pavements to reduce land fill requirements of old millings (as well as asphalt shingle rejects and old asphalt shingles that many asphalt production facilities can now incorporate into the mixes they produce); consequently reducing the consumption of new virgin material resources.