Development of a test to measure the tendency for a hot-mix asphalt to segregate

789798PDFResearch PaperJR99-274, CAPLab 99-3, Project 98-1Bituminous bindersHot mix paving mixturesAsphalt testsTest proceduresMechanical analysisPavement designConnecticut. Dept. of TransportationStephens, Jack E.Dippold, CoryMahoney, JamesConnecticut. Dept. of TransportationConnecticut Advanced Pavement LaboratoryConnecticut Bituminous Concrete AssociationNTL-HIGHWAY/ROAD TRANSPORTATION-Construction and MaintenanceNTL-HIGHWAY/ROAD TRANSPORTATION-MaterialsNTL-HIGHWAY/ROAD TRANSPORTATION-Pavement Management and PerformanceUS Transportation CollectionHot Mix Asphalt tends to segregate during handling and placement. The use of a test to determine the tendency to segregate would assist the user in determining when a mix gradation needs adjustment to avoid construction of a segregated pavement or when special care in handling would assist in avoiding segregation. A number of mixes were subjected to a free fall onto an inclined plane followed by a second free fall from the toe of the inclined plane. The resulting pile of material was divided approximately into halves, that horizontally near the toe of the plane and that farthest away. The two halves were then analyzed for gradation and asphalt content and a computation of the accumulation of percent passing the series of sieves (each 1/2 of the preceding sieve size opening from 18.75 mm to 0.075 mm). The average and standard deviation for three or more tests of each material were then compared. The difference for this value for close and far parts of a mix is the area between the two gradation curves and a measure of segregation occurring. A first estimate is made for a value that differentiates potential problem mixes