Experimental Study On The Composite Modiifed Asphalt And Its Mixture For Birdge Deck Pavement

With the expansion of the highway construction scale, the bridge constructioncareer has achieved unprecedented development. Bridge deck pavement is anindispensable part of the whole, and also is the direct embodiment of the trafficconnections of the bridge. However, the bridge deck pavement which is directly affectedby the wheel load role and is influenced by the deformation of the bridge panel isbuilded on the bridge panel, and the internal stress and strain are more complicated thanthe general pavement. Therefor, the requirements to the overlay materials, from thebridge deck pavement, are much more rigorous than the general pavement materials.At present, the overlay materials which conform to the requirements of the bridgedeck pavement are scarce. In our country, the bridge deck pavement materials andtechnique of the builded bridges are mostly introduced from abroad. But, shortly afterthe use, the bridge deck pavement mostly appears different degrees of diseases. In theusing performance, the asphalt concrete has unique advantages and is widely used in thefield of highway construction, and also the bridge deck pavement mostly adopts suchmaterials. It has been proved that, firstly, the bridge deck pavement materials shouldhave better high temperature stability and fatigue-resistant. The asphalt concrete whichis prone to the permanent deformation and has the unsatisfied fatigue-resistant is typicalviscoelastic materials. So, the general asphalt concrete can’t meet the requirements to thehigh temperature stability and the fatigue-resistant according to the bridge deckpavement.Under the background of rapid development in the current road and bridgeconstruction career of our country, based on the composite modified asphalt (the CMA-E)own developed by the Research Group of Changsha University of Science&Technologyin steel bridge deck, starting from the traditional asphalt mixture and the choice of thematerials, this paper develops a new type composite modified asphalt(the CMA-T)conforming to the requirements of the bridge deck pavement， through using thepolymer and the new type of the asphalt modifier. Firstly, on the basis of understandingthe properties and applications of the various modifiers, combined with the requirementsof the bridge deck pavement in the using performance, the scheme, referencing theCMA-E and choosing SBS, TPS, PE and CB for composite modified asphalt preparation,concludes the influence law of various modifiers addition on the asphalt variousperformance indicators through orthogonal design and range analysis, and, preparescomposite modified asphalt after determining the optimum addition of four kinds of modifiers by considering the performance of asphalt and in use of comprehensivebalance analyzing; secondly, Using SHRP tests, the scheme evaluates the performance ofthree kinds of asphalt, and determines the mixing and compaction temperature ofdifferent asphalt; finally, the scheme makes the analysis and evaluation of the mainPavement Performance of asphalt mixture by the rutting test, bending test at lowtemperature, the water stability and the fatigue property test after determining theoptimum asphalt content of different asphalt mixture with the same gradation;furthermore, this paper makes the economic evaluation of the CMA-T by thecomparative analysis.The results show that with the high temperature stability, fatigue-resistantincreasing significantly and better cost performance, the CMA-T mixture has moreexcellent pavement performance compared with the CMA-E mixture, meets the specialrequirements put forward by the bridge deck pavement to materials, and it has wideapplication space.