Two-lift paving makes a come - Roads & Bridges

alongitudinal joints were later sawedinto the surface.On-board sound intensity (OBSI)tests were conducted on each of thedifferent surface textures. All surfacesshowed lower tire-pavement noisethan a traditional concrete pavement.Opening mindsNearly 100 people—contractors,material suppliers and agency representatives—from15 states attendedthe National Two-Lift Paving OpenHouse in Salina, Kan., on Oct. 15-16,2008.Participants heard presentationsfrom European and U.S. experts,including those involved with theKansas project. They also visitedthe project site and examined theexposed aggregate and other experimentalsurfaces.Additional open houses will beheld as other demonstration projectsare completed over the next twoyears.The National CP Tech Center issetting up demonstration projects inother states in 2009. The goal is tohave two more open houses in thenext year or two, said director TomCackler.Cackler sees two-lift paving as atool that can help “optimize concretepavements to meet local needs—such as specific surface characteristics,scarcity of local materials orrecycling of existing pavements—sothat a long-life pavement can be builtwith an economic and sustainableapproach.”Van Dam said he expects to see alot more versatility with two-lift pavingin the future.“Once we’ve proved the concept,people will start to think about optimizingthe top layer to resist moistureloss, resist cracking . . . There are alot of potential benefits we haven’teven begun to realize,” he said.The ill effects of moisture loss canbe reduced through the use of internalcuring or shrinkage-reducing admixtures,explained Van Dam, andfiber reinforcement can be used tohelp reduce cracking.“When it comes to two-lift paving,”he said, “we’re just scratchingthe surface.”For more information about twoliftpaving and the Kansas demonstrationproject, visit the NationalCP Tech Center’s website at www.cptechcenter.org/projects/two-liftpaving/index.cfm.Shields-Cook is a communications specialist withthe National Concrete Pavement Technology Center,Ames, Iowa. Taylor is an associate director with theNational Concrete Pavement Technology Center.LearnMore!For more information related to this article, goto: www.roadsbridges.com/lm.cfm/rb010919“Word on the Street is Neenah”Road Roller Matsare made with fibers from the almost indestructibleouter husk of the coconut bonded into a vinyl backingand attached on scraper plates to clean frontand rear rollers. They install easier than wovenmats and can be cut to fit without unraveling.For FREE Samples & More InformationBRIDGE SCUPPERS | DETECTABLE WARNING PLATES | COMBINATION INLETSAIRPORT CASTINGS | MANHOLE FRAMES & COVERS | TRENCH CASTINGSVALVES & GATES | INLET FRAMES & GRATES | ACCESS & HATCH COVERSDRAINAGE GRATES | ROLL & GUTTER INLETS800-558-5075 | www.neenahfoundry.comP.O. Box 7038 • Akron, OH 44306 • Fax (330) 773-3254800-321-2381 • E-mail info@mussonrubber.com • www.mussonrubber.comCircle 773NEENAH FOUNDRY CO.IS A SUBSIDIARY OFThese products are to be specified and used under the guidance of qualified design professionals.Circle 774ROADS & BRIDGES • JANUARY 2009 •35