| The highway industry in China has been changed from "construction" to “construction,maintenance and management",and a large number of asphalt pavement is faced with maintenance tasks.Most of asphalt pavement is confronted with the problem that it has integrated structure,but pavement performance of it decreases quickly,it is desiderate to seek the maintenance technology which can save the maintenance cost and quick recovery pavement function,thin overlay may be good to solve the above problems.In recent years,more and more attention has been paid to road traffic safety,and skid resistant of asphalt pavement is closely related to traffic safety.Under the background,high friction course with good skid resistant is developed.The research of this issue is conducted in the thesis,the main research contents include:(1)To make clear the components of friction force between the tire and road surface,antisliding mechanism of the asphalt pavement was studied,and the contact situation of tirepavement under wet condition was also emphatically analyzed,and the grey correlation analysis method was used to analyze the significant factors influencing skid resistant of asphalt pavement,which provided theoretical support for the design of the high friction course.(2)From the point of view of traffic safety,according to the different anti-sliding mechanisms in dry and wet pavement,high friction course was defined separately from the angle of safe headway and hydroplaning critical velocity;Further in order to avoid the rapid decline of skid resistance,it was necessary to defined the high friction from the angle of skidresistance attenuating development.(3)On the basis of the above research,to improve skid resistance and durability of asphalt pavement during the whole service period,the V-S(Volumetrie Mix Design Method Based on Multi-Supporting Framework Condition)was adopted to design high friction course,and the 7.1mm control sieve pore was added to prevent coarse aggregate grading out of control.Based on the test results of crushing and screening,the boundary mesh between coarse and fine aggregate and the grade of fine aggregate were determined to improve the filler-bitumen ratio and the void ratio,and then the skeleton structure was fullly played out to improve the skid resistance.(4)The pavement performances of the design grading HFC-1,HFC-2,HFC-3,HFC-4 and the control grading SMA-5 were verified,the design grading had high-temperature stability,good water stability and anti-wear performance,can meet the requirements of specification.The small accelerated abrasion tester was used to test the five kinds of gradation for long-term skid resistance and the attenuation law was studied.In order to completely valuate the skid resistance,The International Friction Index IFI(F60,Sp)was introduced.(5)The bonding mechanisms of common binder materials used in thin overlay were studied,such as emulsified asphalt,non emulsified asphalt and fiber seal;Moreover,the key construction technologies of thin overlay were also discussed,including the selection of emulsified asphalt with synchronous and asynchronous construction,the spreading of broken stones with asynchronous construction and mixing,paving and rolling of thin overlay,thus for providing theoretical and technical support for maximizing performances and practical application of high friction course. |
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