纵向接缝密度的实践状态.pdf

1、Longitudinal Joint Density State of PracticeDave Johnson,P.E.Alaska Asphalt Pavement SummitAnchorage AlaskaNovember 6,2023Background InformationCase StudiesBest PracticesQuestionsOutlineBackgroundWhat we“know”Asphalt Institute study(2012)showed that longitudinal joint construction is an area where c

2、onsensus is nearly unachievable,but that with attention to detail,we can produce good joints with differing techniques.Longitudinal Joints are most pavements weakest pointTypically,joint density is 2%less than mat densityUnsupported edge will usually have the lowest densityJoint density specificatio

3、ns typically 89-92%of TMDFor each 1%loss in density=about 10%loss of lifeAreas of General AgreementCase Studies August 2021 26-Mile Project State Highway#8 3”CIR Two 1.5”12.5 mm Superpave Lifts 58S-28(MSCR)Mix Temperatures 250-280F at Paver 90.5 Joint Density RequiredNorth DakotaND Highway 8Notched

4、Wedge ConfigurationWillow Design DevisePaveScan RMD 2.0Unique FeaturesPhotos and graphics from Asphalt Pro Magazine and Willow DesignUnique FeaturesBreakdown Roller CAT OscillatoryIntermediate Roller(s)CAT Vibratory(Primarily used)Sakai Vibratory Pneumatic(Used on hot days when tenderness appeared)F

5、inish Roller CAT Vibratory in Static Mode Results94.8%Joint Density(93.9%Matt Density)Courtesy of Asphalt Pro MagazineState Trunk Highway 237.5-Mile Project 22,230 T 19 mm 2.25”1st lift 18,289 T 12.5 mm 1.75”2nd lift 58-28S(MSCR)290F at Breakdown Roller90.5 Joint Density RequiredWisconsinSTH 23Uniqu

6、e FeaturesPaving Speed Set as 22ft/minBreakdown Roller Sakai High Frequency VibratoryIntermediate Roller(s)BOMAG PneumaticFinish Roller BOMAG SteelCourtesy of Asphalt Pro MagazineUnconfined Joints206 Nuclear TestsAveraged 93.3%Confined Joints 224 Nuclear TestsAveraged 94.5%+95%of joints received max