| Preventive maintenance is a new concept of asphalt pavement maintenance,which takes some economic measures to maintain the pavement system,delay damage,maintain or improve the pavement function without increasing the bearing capacity of pavement structure.There are many kinds of preventive maintenance technology for asphalt road.In recent years,micro-surfacing technology and Nova-Chip technology,which have been recognized and favored,have highlighted their increasingly defects.In order to meet the urgent needs of preventive maintenance of high-grade roads in the future,it has become a research hotspot to explore a kind of wearing surface technology for preventive maintenance,with the characteristics of super-bonding,high waterproof,high skid resistance,high temperature resistance,low noise,crack resistance,low carbon,energy-saving and environmental protection,simple technical requirements for construction,moderate economic cost and being widely used.Super bonding wearing course is developed on the basis of micro-surfacing technology.This technology also draws lessons from the characteristics of Nova-Chip technology,using emulsified asphalt sprinkler to spray modified emulsified asphalt mixture,using micro-surfacing paver to pave ultra-viscous cold-mix mixture with glass fiber,after curing to form a new wearing surface,is a new road maintenance technology.This paper focuses on the study of SBS modified emulsified asphalt for synchronous spraying and bonding,SBS modified emulsified asphalt for mixture,selecting of aggregate,filler,fiber,and other additives,design of mixture proportion and quality controlling of wearing surface in the course of construction.Through the optimization of various material formulation and mixture gradation,the technology of super bonding wearing course has been successfully applied to the preventive maintenance of asphalt pavement in humid and hot areas in southern China.In this paper,through the study of SBS modified emulsified asphalt for synchronous spraying and bonding,SBS modified emulsified asphalt for mixture,selecting of aggregate,filler,fiber,and other additives,design of mixture proportion and construction of the test section,the following conclusions are obtained:(1)Bitumen was changed into SBS modified emulsified asphalt with excellent performance(PCR)by SBS modifier.The obtained SBS modified emulsified asphalt can meet the requirements of the adhesive layer of Super bonding wearing course.(2)Bitumen was changed into SBS modified emulsified asphalt with excellent performance(BCR)by SBS modifier.The obtained SBS modified emulsified asphalt can meet the requirements of the mixture of super bonding wearing course.(3)After comparison and considering the economic influence,diabase,which is widely distributed in Guangdong Province,is selected as the main mineral.The other additives,such as ordinary portland cement and glass fiber,can meet the road performance requirements of Super bonding wearing course.(4)Through the mix ratio design,it was determined that“mineral material:cement:fiber:emulsified asphalt:water=100:1.02:0.2:11.0:6.0(mass percentage)”was used as the mix ratio in the test section.(5)According to the results of indoor systematic research,the test section(about10000m~2)of super bonding wearing course has been paved successfully both on the Hui-He Highway and the West Second Ring of Guangzhou City-Round Highway by step-by-step super bonding wearing course.Opened to public traffic in the past two years,the test section pavement performance is still in good condition and achieved the desired effect,which proves that this technology can be applied for the asphalt pavement preventive maintenance in hot and humid region of southern china. |
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