Better Roads

March 2014

Better Roads Digital Magazine

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Page 22 of 31

PB ASPHALT PATCHERS WORLD CLASS PATCHERS SINCE 1957 $W3%ZHXQGHUVWDQGSRWKROHSDWFKLQJ)RURYHU\HDUVZHKDYH GHVLJQHGTXDOLW\3DWFKHUVWKDWDUHGXUDEOHORQJODVWLQJDQGEXLOW IRU\HDUURXQGXVH:KHQ\RXQHHGDSRWKROHSDWFKHUORRNWR3% ZHKDYHVROXWLRQVWRPHHW\RXUQHHGV3URYHQ3DWFKHUVDYDLODEOH ZLWKDYDULHW\RIIHDWXUHVDQGFDSDFLWLHVIURPWRFXELF\DUGV PB Corporation I 5778 W Barstow Ave I Fresno, CA I 800-350-8521 TRUCK MOUNTED HOOK LIFT DUMPBODY SLIP-IN TRAILER MODELS &DOO 7H[W,1)2WRRUYLVLWZZZEHWWHUURDGVFRPLQIR Better Roads March 2014 21 7.5-mile stretch of Interstate 10 near Palm Desert. Granite used a gap graded Superpave mix that blended crumb rubber into PG 64-16 virgin asphalt. The California Department of Transportation (Caltrans) re- quires an extender and some high natural rubber to be used in combination with the crumb rubber. The total CRM modifi er was 18 percent of the binder by weight, says Jim Marsolino, project quality control manager for Granite. Virgin binder was 82 percent. "We blended it with our portable rubber plant," Marsolino says. "We bought the crumb rubber, the extender and the natural rubber from suppliers, and dumped Super Sacks into our hopper. That mixture goes into a reaction vessel where everything gets mixed together to make the binder. It reacts for a certain length of time based on what the spec is for the rubber. Once it reaches the specifi ed viscosity, it goes to our holding tank, and is then used for the manufacture of rub- berized hot mix asphalt." The reaction temperature was 393 degrees. The mixture worked well, Marsolino notes. Caltrans requires a method specifi cation for thin lifts of asphalt instead of a density spec. Granite had to complete a certain number of roller passes at each level – breakdown, intermediate and fi nish stages – before the temperature of the asphalt dropped below certain levels. Steel-wheeled rollers handled compaction for each of the three stages. "We ran the plant at 180 to 200 tons per hour, paving at night," Marsolino says. "We paved one lane at a time, and whatever we milled out in one night had to be paved that same night." He said the contractor was able to pave some 1,400 tons per night in an eight-hour shift. Adds D'Angelo: "History has demonstrated that CRM bind- ers will perform well in rutting and cracking. Using the new testing techniques, CRM binders can be compared directly to the polymer modifi ed binders. This clearly demonstrates that CRM can be used in place of, or in combination with polymer to provide a high-quality performance graded (PG) binder." Daniel C. Brown is the owner of TechniComm, a fi rm that specializes in communications for the construction industry. 7H[W,1)2WRRUYLVLWZZZEHWWHUURDGVFRPLQIR

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