| Highways are the main artery of economic development.Since the founding of the People’s Republic of China,Tibet’s transportation has made considerable progress,and highways have always dominated the transportation system in Tibet.Asphalt pavement is widely used in highways of all grades due to its excellent road performance.However,asphalt is a temperature-sensitive organic material,which inevitably ages during its service,and this ageing is irreversible in its natural state.The temperature in the Qinghai-Tibet Plateau is relatively low,the temperature difference is large,and the ultraviolet radiation is extremely strong.Asphalt pavement is more prone to aging than the plain area,resulting in a decline in its road performance.Preventive maintenance is a kind of maintenance measures taken when there is no obvious structural damage on the asphalt pavement,which can save the maintenance cost and improve the service level of the asphalt pavement.Based on the special climatic and environmental conditions of the Qinghai-Tibet Plateau,this study developed the automatic production equipment for the light-shielding(LS)preventive maintenance in the Qinghai-Tibet Plateau based on the preliminary laboratory research of the research group,so that the LS preventive maintenance can be mass produced.As for the road performance of maintenance agents,it was found that preventive maintenance agent has greatly improved the service performance of asphalt pavement.On this basis,with Dongfeng Duolika as the chassis,a corresponding preventive maintenance agent sprayer was developed through cooperation with relevant manufacturers.The study found that the LS preventive maintenance agent is composed of 2 powders and 3 solvents.No chemical reaction occurs between the components,but only physical blending.The preventive maintenance agent has good reduction performance,water sealing performance and permeability performance.The researched preventive maintenance agent automatic production equipment is composed of storage module,transmission and transportation module,metering module,pipeline cleaning module,mixing and mixing module and electronic control module.The MODBUS protocol is selected for the field bus.The spraying truck can precisely control the amount of spraying and can also spray preventive maintenance agent and emery at the same time to improve the road performance of asphalt pavement without reducing the sliding resistance.On this basis,a test road section was selected for maintenance in Lhasa,and structural depth,friction coefficient and water permeability coefficient tests were conducted respectively,and it was found that the preventive maintenance agent had a significant improvement effect on various pavement performance indicators.Finally,the construction costs of LS preventive maintenance,grouting and thin-layer overlay maintenance are compared.The results show that compared with thin-layer overlay maintenance,the direct cost can be reduced by 20%.At the same time,LS preventive maintenance technology can effectively improve and maintain the durability of the road surface performance,greatly reducing the cost of road maintenance and bringing considerable economic benefits. |
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