Study On The Compatibility Of Asphalt Hot In-place Recycling Of Asphalt Pavement

With the rapid development of highway in China, there are so many heavy highwaymaintenance and repair tasks has been brought that the regeneration technology of asphaltpavement is increasingly concerned in the highway maintenance and repair. Recycled asphaltmixture is usually composed of new asphalt, new aggregates,old asphalt, regenerant, oldaggregate according to the different proportion design. The compatibility of old asphalt,regenerant and new asphalt is directly related to the road performance of recycled asphaltmixture. Based on the specific project, the compatibility of asphalt hot in-place recycling hasbeen researched providing the basis of rational selection of regenerant and new asphalt.At first, this paper makes an analysis of the old pavement materials byrecycling.Aaccording to the aging of asphalt and the regeneration mechanism, type Aregenerant、type B regenerant and type C are matched with the old asphalt in accordance with3%,5%,7%,10%. Through performance test index,6%type A regeneration with the optimalcompatibility of old asphalt regenerant is determined to regenerate old asphalt.Secondly,6%type A regeneration of old asphalt regenerant is blended with SK-70#asphalt, China-70#asphalt in accordance with10%,20%,30%,40%to take the compatibilitytest. Through comprehensive analysis of relevant performance test index, SK-70#asphaltcontent is optimized and the new asphalt dosage range is determined to be30%~40%.After that, the recycling of asphalt aging, blending6%A regeneration agent of recycledasphalt,30%SK-70#asphalt mixture of asphalt mixture by using infrared spectroscopy.Theinfrared spectrum analysis shows that the presence of the carbonyl group is an important featureof asphalt aging, the number of Sulfoxide base after asphalt aging will increase. Due to physicalcommunion, the component of regenerant causes the change of the recycled asphalt and thecomponent of new asphalt sets off the change of mix asphalt.The absorption peak of-CH2-isthe strongest in both recycled asphalt and mix asphalt.Finally, road performance of compound mixing recycled asphalt mixture with new asphaltmixture of different blending proportion is researched. According to the road performance testdata of new asphalt mixture under different blending proportion and regeneration asphaltcompatibility test results of actual adding asphalt and recycled asphalt with different blendingproportion,combine with the condition of project’s geographical location, climate and theeconomic benefits, the mixture adding20%of new asphalt is determined.