Local Strain Analysis Based On The Approximate Calculation Method And Estimation For Fatigue Life Of Asphalt Pavement

Fatigue cracking of asphalt pavement is a common failure modes， The cracks not onlydestroy the integrity of the pavement structure and impact aesthetics of the road， the moreserious is that the water enter inside the pavement structure from cracks and then into thesubgrade structure caused by water damage，Greatly shorten the service life of pavementstructure. Fatigue cracking of the asphalt pavement life prediction is no clear and effectiveway at home and abroad. Base on the world-wide researches in the paper，proposed fatiguelife prediction method based on local strain.In the first place, base on the world-wide researches, the reasonable and feasibleconditions of direct tension fatigue testing for asphalt mixture are bring forward. Themonotony tension curve equation of asphalt mixture is found, and the monotony strainrigidification coefficient and intensity coefficient are also put forward. With the way ofmultilevel and multi-specimens, the circular stress-strain curve equation of asphalt mixture,and the circular strain rigidification coefficient and intensity coefficient are also put forward.Asphalt mixture has such prosperities of circular rigidification and circular relaxation.Considering the effect of average stress, strain-life fatigue equation of asphalt mixture isestablished. From that, the minimum and maximum of cracking tension strain of asphaltmixture are specified. Compared to the fatigue testing of the slippery and chipped specimens,the Peterson regressive equation, fatigue translated coefficient and gap sensitivity coefficientof fatigue gap coefficient of asphalt mixture are calculated. And then, base on elastic finiteelement method numerical calculation, influence of load strain and thermal strain fromvarious factors is analyzed. Base the way of uniformity design, the applied regressiveequations of thermal strain and load strain are regressed. With the minimum remaining energyprinciple of guard system of elasticity theory, the translation between nominal stress-strainand local stress-strain under any stress condition is deduced, and is applied to the circular loadand chipped structure. Calculation methods to local strain of asphalt pavement includedKf－Neuber equation�'�ESED are put forward. Finally, base on circular stress-strain curveequation and strain-life fatigue equation of asphalt mixture and the method of calculatinglocal strain, the method of forecasting the fatigue cracked life of asphalt pavement with localstrain is put forward. It can be as basis of controlling the fatigue cracked in asphalt pavementdesign and then perfect the design method of asphalt pavement.