| The asphalt pavement in Guizhou Province is a typical mountainous highway with karst landform in southern China.During its service,it suffers from severe environmental effects such as heavy traffic,high temperature and rainy weather in summer and freezing in winter,which leads to frequent pavement diseases and seriously affects the service performance and service life of asphalt pavement.Through field investigation,it is found that cracks are the most common diseases of asphalt pavement diseases in mountainous areas of Guizhou Province,and if they are not repaired in time in the early stage,they will cause serious pavement structure damage with rainwater invading the subgrade.Crack repair is an important link in preventive maintenance,which has obvious advantages in delaying the development of cracks,prolonging the service life of pavement and saving maintenance costs.Based on this,this paper studies the crack repair technology of asphalt pavement in Guizhou Province.The specific research contents and conclusions are as follows:(1)Firstly,the service environment and characteristics of asphalt pavement in Guizhou are studied.It is found that the natural environment of asphalt pavement in Guizhou is characterized by high terrain in the west and low terrain in the east,obvious vertical climate change,frequent disastrous weather in the same period of rain and heat,and natural conditions have great influence on pavement performance.(2)Secondly,the paper investigates and analyzes the crack situation of asphalt pavement in Guizhou and its influencing factors,and summarizes the classification and performance characteristics of commonly used crack repair materials;Five kinds of crack repair materials are selected for indoor performance tests,and their properties such as high temperature resistance,low temperature resistance,invasion resistance,corrosion resistance and aging resistance are discussed respectively.At the same time,the construction properties such as suitable irrigation temperature and setting time,shear resistance and tensile resistance are discussed comprehensively.The aging coefficient is introduced to evaluate its aging performance.The results show that its aging performance is Jiage > Road Maintainer > SBS modified asphalt > RT-A>70#hot asphalt.(3)Then,by designing the finite element model of asphalt pavement structure,the stress of crack repair structure under different load types and changing crack width at three temperatures(0℃,20℃ and 50℃)is compared and analyzed in detail,and the theoretical maximum shear stress of repair structure is 0.603 MPa,0.576 MPa and0.206 MPa,respectively,which is compared with the indoor test shear stress of repair materials.In the same way,the road performance effect of the repair material is verified after the tensile stress results are processed.(4)Finally,through the practical engineering application and tracking observation records of the repair materials in Rongjiang section of Guizhou,the results show that the performance of the special materials for crack repair,represented by Jiage joint sealant,is very ideal,and the comprehensive surface is the best in terms of repair effect and service life,and it is suitable for high-grade asphalt pavements such as expressways,first-class roads,urban expressways and trunk roads with high pavement pressure,busy traffic and high requirements for crack repair.The performance of heating construction materials is poor,but it can also meet the index requirements of crack repair,and it is suitable for low-grade asphalt pavement with relatively small pavement pressure and small traffic volume,such as secondary and below roads,branches and secondary roads.Normal temperature construction materials are only suitable for temporary emergency repair under unfavorable conditions such as wet cracks after rain. |
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