Research On Performance Of Volcanic Ash Asphalt Mastic

Asphalt pavement damages occur frequently under the complex and changeful natural conditions and vehicle loads. Application of polymer modified asphalt reduces early damages of pavement to some extent, while increases the construction cost. Mineral filler modifier research is one of the fields of modified asphalt and thought to be one technical approach to improve asphalt mixtures performance, save construction cost and reduce early damage of asphalt pavement.In virtue of advanced test instruments, based on the characteristics analysis on the fine volcanic ash—a new mineral filler type modifier, in order to achieve a comprehensive improvement of the asphalt mixtures performance through asphalt mastics modification , with a main investigative line " rheological properties of asphalt mastic- microstructure of asphalt mastic-asphalt mixture performance verification ", the paper carries out the study on the effect of sigle modification by fine volcanic ash and composite modification by fine volcanic ash and multi-materials. Simultaneously, interaction mechanism analysis between fine volcanic ash and asphalt and comparison tests of performance index for fine volcanic ash modified asphalt mixture are conducted to guide and verify the study of mastics modification.Compared with single modification,high temperature stability of composite modified mastics and mixtures by SBS and volcanic ash are increased remarkably, meanwhile, low temperature cracking performance has different degrees of enhancement depending on volcanic ash varieties but not basically equal to mineral powder mastics.Unifying high-and-low temperature performance, the basic contradiction of asphalt pavement, has important practical significance for weight traffic highway section rutted seriously in northeast China. Modification mechanism analysis based on electron microscope scanning demonstrate that it is due to micropore structure particularity of volcanic ashes.In order to fully explore performance of volcanic ash modified asphalt mixture, a exploratory mixtures test with adjusted aggregate gradation is conducted, reducing fine aggregate proportion and increasing composite modified mastics by SBS and volcanic ash. Results indicate high temperature stability and low temperature cracking resistance of adjusted mixtures are significantly improved ,which implies one important message:there exhibited some limitations about traditional design theory and method of asphalt mixtures when asphalt mastic performance reaches a certain level.The paper shows asphalt mixtures with volcanic ash singlely or compositely modified mastics both have good performance-price ratio and the study has actual application value. The concept of composite modified asphalt mastic, distinctive from traditional mineral filler type asphalt mastic which mainly emphasizes the specific surface energy and filling effect of fillers, is brought forward based on example of composite modified asphalt mastic with SBS and volcanic ash , and it has theoretical value.