According to The Asphalt Handbook, published by the Asphalt Institute, pavers are designed to spread hot mix asphalt in a "uniform layer of desired thickness and shape or finishes the layer to the desired elevation and cross section, making it ready for compaction." Pavers do this work on either pneumatic-tires or crawler tracks and can place a layer of HMA from 1 in. to 10 in. thick and from 6 to 32 ft. wide at working speeds ranging from 1 to 70 fpm.
But an asphalt paver is really three systems in one. A tractor powers the paver, a material handling system moves hot mix from the hopper to the screed, and the screed "levels and profiles" the material. How this all gets done varies from one manufacturer to another, with the goal being to provide a smooth, homogenous mat out the back end of the paver.
Bomag America's John Hood says a paver's material transfer system is the Number One wear part of the machine. "It's grabbing aggregate and pulling it across steel, and that's a high-wear effect," Hood says. "If I were a contractor looking at a hopper and material transfer system I'd want, first, a paver with a large hopper capacity, hopper wings that are heavy duty, and conveyor and drive sprockets that are made of heavy duty material, heat treated or something," Hood says. "I'd want augers made of abrasive-resistant steel or heat-treated."
Hood says that especially for commercial pavers contractors need to pay close attention to their ability to service the machine.
"I'd want to know what it takes to service each of the material handling components," he says. "How easy it to adjust the chains, to maintain the augers, those types of things. Ease of maintenance is crucial to a commercial contractor."
Bomag America's John Hood and Volvo's Larry Spring provide more information and insights on material handling systems in the "Featured Equipment: Pavers" article in the October/November issue of Pavement Maintenance & Reconstruction.