Study On The Application Of Super-adhesive Cover(NovaPave) To Preventive Maintenance Of Highway Asphalt Pavement

With the development of economic,China's road construction has also begun to shift from the incremental market of "large-scale construction" to the market that focuses on maintenance and pre-maintenance.As an important way to prolong the service life of roads and improve road performance,Chinese government has attached high importance to the road pre-maintenance measures.At present,there are many pre-maintenance technologies have been used in China,including: micro-surface,asphalt thin layer,fog seal layer,etc.In view of the different damage levels of the original pavement,the above technologies have their own characteristics.The asphalt thin layer has the advantages of excellent anti-slip performance and good noise reduction effect.However,there are still some issues of asphlt thin layer need to be resolved,such as the lack of uniform specifications and the controversial issues of key performance evaluation indicators.Therefore,on the basis of research on several types of asphalt thin layer,this paper improved asphalt thin layer and a new type of asphalt thin layer was designed whose name is super-adhesive cover(Nova Pave).The super-adhesive cover was comprehensively evaluated from the aspects of raw material analysis,gradation design,indoor performance and actual engineering.Firstly,this article comprehensively compares the basic performance and rheological performance of the copolymer-nanocomposite modified super viscous bitumen(hereinafter referred to as super viscous bitumen)used in ssuper-adhesivecover and the two types of usual high viscous bitumen on the market.It was found that the three high-viscosity asphalts could met the design requirements in basic performance and rheological performance.Secondly,the pull-out strength of the three interlayer adhesives was evaluated by outdoor field pull-out test.The test showed,the selected materials could well match the requirements of the super-adhesive cover.Then,referring to the theory of maximum density curve and particle interference theory,this paper used Marshall design method to design the gradation curve and the oil-rock ratio of super-adhesive cover,and finally get the design of super-adhesive cover.This article also carried out indoor performance experiments on three types of thin asphalt layer.Tests results had proved that all road performance indicators of super-adhesive cover met the design requirements,and its high temperature performance and water resistance were excellent.On the basis of indoor research,a test section was constructed on the K3408+700—K3409+310 section of the southbound direction of the north extension of the Guangzhou Airport Expressway to verify the actual road performance.This article detailed the construction process,organization and quality control and carried out a number of road performance tests before and after construction.The test results showed that the super-adhesive cover could significantly improved the anti-skid performance and smoothness of the road surface,and reduced the noise.At the same time,because the super-adhesive covers has a certain porosity,which means it can prevent the formation of a water film on rainy roads.The life cycle economic benefits of super-adhesive cover are good,and it has certain advantages in asphalt thin-layer which have the potential for application.