Preparation And Performance Evaluation Of Pavement Maintenance Materials Around Municipal Roads

Urban pipe network is an indispensable part of urban infrastructure and is called "urban artery".Inspection Wells as an important part of city pipe network,in principle should be deployed in urban road outside,but under the influence of city pipe network and the road width,a large number of manholes in urban roads within the scope of urban roads,under the repeated action of vehicle load,manholes and paving around manholes often appear near the settlement of manholes,the paving around manholes sag and cracking and other diseases.The disease of manholes and the paving around manholes greatly reduces pavement smoothness and seriously affects vehicle comfort and safety.To solve above problems,based on the city road inspection shaft of the paving around manholes and manholes as the research object,analyzing the paving around manholes' the destruction mechanism of pavement under vehicle load,put forward the paving around manholes' material performance control target,develop a performance the paving around manholes' patching material,the paving around manholes' driving comfort is poor,easy to solve the paving around manholes' broken problem,has very important social meaning and engineering value.To study manholes and paving around manholes the destruction mechanism of pavement and pavement diseases in inspection manholes and paving around manholes,on the basis of people-car-covers the coupling vibration model is established,dynamic characteristics analysis of vehicle,the paving around manholes mechanics response of the vehicle loads,explore key factors influencing pavement damage the paving around manholes,reveals the damage failure mechanism.The results show that subsidence(or bulge)and cracks are the main diseases of manholes and paving around manholes,while damage diseases are relatively few and deformation diseases are very few.The settlement of the manholes is mainly distributed in the range of 0?10mm,and the maximum clearance of the paving around manholes is mainly distributed in the range of 5?20mm.The larger vehicle speed,slope difference,settlement of manholes and uneven road surface paving around manholes lead to the increase of the impact load of the vehicle in the manholes and the paving around manholes,resulting in the increase of the bottom tensile strain of the pavement layer the paving around manholes and the bottom tensile stress of the base layer,and the reduction of the fatigue life of the surface layer and the base layer.The impact load and the insufficient compacting degree of each structural layer are the important causes of the manholes and the paving around manholes.In order to solve the problem of pavement damage around the manholes,the fatigue life and flexural strain were proposed as the mechanical control indexes of the curing materials,and a modified asphalt and mixture with high strength,high toughness and fatigue resistance was developed.In order to meet the requirements of pavement maintenance,pavement maintenance materials around the well were developed.Micro-carbon fiber(MCF)and SBS and MCF,SBS and SBR were used to obtain SBS/MCF composite modified asphalt and SBS-SBR/MCF composite modified asphalt.Conventional indexes and microscopic properties of modified asphalt were studied,and conventional SBS modified asphalt was used as comparison sample.The results show that MCF and SBR can decrease the penetration,and increase the softening point,ductility and dynamic viscosity.The viscosity and toughness tests show that the addition of MCF can effectively improve the viscosity and toughness of asphalt.FTIR test showed that no new functional groups were generated when MCF was added,indicating that no chemical changes occurred when MCF was added,but only physical blending.In order to study the high temperature rheological properties and low temperature creep properties of composite modified asphalt,the rheological properties of different composite modified asphalt were analyzed based on rotational viscosity test,dynamic shear rheological test and low temperature bending beam rheological test.The results show that the dynamic viscosity not only meets the requirements of the code,but also achieves good workability under the dosage of 6%SBS+0.8%MCF.The addition of MCF plays a reinforcing role between asphalt and SBS,and can improve the high temperature,viscoelastic properties and high temperature deformation resistance of SBS modified asphalt.The maximum S value and minimum M value are obtained with the addition of 6%SBS+0.8%MCF,indicating that the low temperature performance is higher than other modified asphalt.All modified asphalt have the same low temperature classification,which is PG-28.In order to study the road performance and mechanical properties of modified asphalt mixture,rut test,freeze-thaw splitting test,low-temperature bending test,four-point bending test,friction coefficient test,structural depth test,seepage test and dynamic modulus test were carried out,and the main curve of dynamic modulus was obtained by fitting.Results show that the MCF join the mixture of high temperature,low temperature toughness and fatigue property are improved significantly,improve effect on the stability of water is limited,its against sliding and seepage effect is good,eventually found 6% SBS + 0.8% MCF modified asphalt mixture with the best comprehensive performance and used for the paving around manholes when the pavement maintenance can significantly improve the pavement service life,reduce maintenance frequency.