Research On Application Of Fog Seal With Sand On Asphalt Pavement Of Airport In Xinjiang

Asphalt pavement has gradually become the main mode of old cement concrete pavement reconstruction in China’s airports because it can meet the requirements of non-stop construction.However,under the cyclic action of load and environmental factors,it is prone to early damage such as loose aging and aggregate exposure.As an effective preventive maintenance technology,the Fog seal with sand can block the micro-cracks and pores of the pavement and inhibit the loose spalling of the aggregate,which has a great application prospect in the preventive maintenance of asphalt pavement.Based on the science and technology project of Xinjiang Airport Group,this paper puts forward the performance evaluation index of Fog seal with sand of airport asphalt pavement,and explores the performance evolution law of Fog seal with sand layer of airport asphalt pavement under load and complex environmental conditions,which is of great significance to promote the scientific maintenance of airport asphalt pavement.Based on the statistical analysis of the temperature data of typical cities in Xinjiang,the high temperature climate zone of typical cities in Xinjiang is divided into hot summer I₁ area,hot summer I₂ area and hot summer I₃ area on the basis of the climate division of Specifications for asphalt pavement design of civil airports.The low temperature climate zone is subdivided into winter cold II₁ zone,winter cold II₂ zone,winter cold II₃ zone and winter cold II₄ zone.Based on the investigation of Tacheng,Karamay and Yining airports,it is found that the early diseases of asphalt pavement are mainly manifested as asphalt film peeling,aggregate exposure and microcracks.The preventive maintenance requirements of airport asphalt pavement are analyzed,and it is proposed to determine the fog seal with sand applied to airport asphalt pavement through the comparison of drying,wear resistance,skid resistance,hydrophobicity and bonding properties.Based on the orthogonal theory,the orthogonal test was designed.The influence of anti-sliding particle type,particle size,particle content,emulsion type,emulsion content on the performance of fog seal with sand materials was clarified by extremum difference analysis,and the influence mechanism of each factor on the performance of materials was explained.The matrix analysis method is used to carry out the multi-objective optimization design of the composition of the fog seal with sand material,and the optimal material composition is determined:the anti-sliding particle is emery,the particle size is 0.3～0.45mm,the particle content is 0.5kg/m²,the fog seal emulsion is product 1,and the emulsion content is 0.4kg/m².The rolling brush accelerated wear equipment is developed.According to the actual working conditions during the service period of one year after the construction of fog seal with sand,considering the factors such as load,temperature,freeze-thaw and immersion,the indoor wheel load-rolling brush coupling accelerated wear test is designed.The evolution law of wear resistance,skid resistance and impermeability of fog seal with sand on asphalt pavement under the action of load and complex environmental factors is analyzed and clarified.The results show that after one year of coupling effect of load and environmental factors,the mass loss rate of fog seal with sand is 22.83%.The surface BPN and TD of fog seal treated asphalt specimens are attenuated to 53 and 0.79 mm respectively,and the water permeability coefficient is increased to 83.2 ml/min.Based on Tacheng,Karamay and Yining airports,the on-site construction of fog seal with sand was carried out,and the key performance indexes of pavement before and after construction were tested.The results show that the anti-skid index of pavement can be restored to more than 91%of the pre-construction level one week after the completion of open traffic,indicating that the fog seal with sand can meet the preventive maintenance needs of airport asphalt pavement in Xinjiang.