Analysis On Friction Coefficient Of Asphalt Pavement Under Coupling Action Of Load And Running Speed

With the rapid development of the motor transport in China,automobiles have gradually become an indispensable means of transportation.At the same time,people's safety are threatened by the increasing traffic accident year by year.As the vector of automobile,the pavement anti-slide performance has significant effect on driving safety,and the friction coefficient of tyre with road may directly affect pavement skid-resistant performance.There exists a lot of influencing factors in pavement skid-resistant performance,for example,pavement materials gradation type,running speed,vehicle load,tire pressure,tread pattern type and so on.However,in our country,the evaluation method of indoor anti-slide performance is simple at present,researchers only use pendulum-type frictiograph and apply the sand-laying method to test the forming specimen surface properties simply,while the pendulum-type frictiograph has disadvantage that its testing stylebook is small and the test results are significant affected by artificial factors,the testing method can not fully characterize the friction state of tire and pavement in the process of driving in practice,and it can not weigh the anti-slide performance of the sample surface which has been tested a long time,it is much slower than the requirement to the pavement high skid-resistant performance.So that,that testing real time rolling coefficient of sliding friction and the change of anti-slide performance under long-tern loading will be a new task for our investigation.The author's essay studies four parts as follow:Firstly,This paper gives a introduction of friction coefficient gauge's advantages and disadvantages and analytical models in domestic and abroad and analyzes the factors which has influence on mechanism of the friction coefficient of road surface.Secondly,choose three factors:pavement materials gradation type,vehicle speed and vehicle load,the author develop a new type of friction coefficient gauge,this machine can achieve the aim measuring the contact friction forces in tire-pavement interaction system through changing the type of pavement materials which is measured.According to debugging and installation at the earlier stage,the author verifies the feasibility and security of instrument and makes operation method of it.Thirdly,design for orthogonal experiment targeted three kinds of typical gradations:AC-13?AC-20 and SMA-13.Taking the friction coefficient as the evaluation index,it shows that with the speed increasing friction factor would be decreased,the overall trend of the testing,friction coefficient increasing with the loading increased,the speed is the significant factor,and according to calculation,with the increase of the nominal maximum aggregate size,the friction coefficient increases sharply;the friction coefficient of the gradation SMA is bigger than AC.Fourthly,use three kinds of formed grading typical rutting plates to make attribution experiment with three kinds of loads.Lastly,at the same time,the author uses sand laying to compare the texture depth difference of different grading which are effected by different load,it draws a conclusion:comparing with loading,gradation has great effects on the difference of texture depth,the wear resistance increasing with the nominal maximum aggregate size increasing,comparing the ability of wear resistance,gradation SMA is stronger than AC.