Better Roads Digital Magazine
Issue link: http://read.dmtmag.com/i/376195
Better Roads September 2014 17 Make precision application a reality with the Hi-Way ® Xzalt ® . Featuring a unique directional spinner, the Xzalt allows operators to broadcast a 70:30 ratio of dry/liquid material precisely on one, two, or three lanes all from the convenience of the cab. The mixed material delivered produces less bounce and improves road adhesion, virtually eliminating over-application on roadside shoulders. The Xzalt also allows operators to achieve higher application speeds and maintain longer routes with fewer spreaders, improving their return on investment (ROI). ÊnääÎÈΣÇÇ£ÊUÊÜÜÜ°}Ü>ÞiµÕ«iÌ°VÊÊUÊ^ÊÓä£{Ê}Ü>ÞʵիiÌÊ «>Þ°ÊÊÊÀ}ÌÃÊÀiÃiÀÛi`°Ê Determine your ROI with the Xzalt by becoming a VIP at www.HiWayVIP.com. 7H[W,1)2WRRUYLVLWZZZEHWWHUURDGVFRPLQIR fl ighting in the drum. Tully says his price for a 60 percent RAP mixture is about $58 per ton, placed in the truck but not paved. By contrast, an all-virgin mix costs about $80 per ton in New York City. "In our market, for every 10 percent of RAP that you increase, you save $3.50 per ton," says Tully. At the Green Asphalt plant that runs 100 percent RAP, pro- cess developer Bob Frank says he bought used components to create the machine, but the pollution control device is patented and is unique. It can run either as a counterfl ow plant or paral- lel fl ow, but is currently set up in the counterfl ow confi gura- tion. (The RAP enters the drying drum at the opposite end from the burner.) Green Asphalt fractionates RAP into three sizes: a sand frac- tion, a nominal half-inch size for surface mixes, and a nominal one-inch size for base layers. "They can adjust or blend those three sizes to make a full complement of mixes," says Frank, who is the founder of RAP Technologies, the company that developed the 100-percent RAP process. Similar to many early entry counter-fl ow drum plants, the plant exposes RAP directly to the burner fl ame, but not for long. None of the recycled binder gets burned off, Frank says. "You create blue smoke, that's correct," he says. "But you don't burn off or irrevocably damage the asphalt binder." We asked how the blue smoke is controlled. "A multi-stage pollu- tion control device fi rst removes airborne particles and a fi nal fi lter removes blue smoke," says Frank. Recycling agents, essential to producing a quality product at RAP contents above 25 percent, are introduced at the dryer discharge. Frank says the plant can handle RAP with any moisture con- tent, because it is heated directly. "We're not dependent on heat transfer from the fresh aggregate to heat and dry the RAP," he says. "Green Asphalt has been making commercial mixes since 2011," Frank says. "It follows from a demonstration project hosted by New York City that went into operation in Novem- ber 2001 and paved streets across Queens Borough with 100 percent mix. Those streets are still holding up to the rigors of New York winters and traffi c."