Research On Fatigue Performance Of TLA Modified Asphalt Mixture

Aiming at fatigue damage which is one of primary distress of now in highway asphalt pavements, the fatigue performance of TLA modified asphalt mixture was researched in the paper according to the asphalt pavement engineering in the First Loop Expressway of Fast Main Highway of Foshan City in Guangdong Province. The following conclusions were obtained:1) The raw material properties tests, mixture ratio design and pavement performances tests of TLA modified asphalt mixture and ESSO asphalt mixture AC-13C were made according to the actual engineering of surface layer of asphalt pavement in DS19 bid section of eastern line in the First Loop Expressway of Fast Main Highway of Foshan City, so the materials of fatigue tests were determined.2) Fatigue tests to TLA modified asphalt mixture and ESSO asphalt mixture were made. Four-point bending fatigue test on small beam specimens and indirect tensile fatigue test on cylindrical shaped specimens were used to evaluate the fatigue performances of them. The fatigue tests were made with stress controlling mode, test temperature was 15℃, the loading frequency was 10Hz, the loading waveform was sine wave. The tests results indicated that the fatigue life-span of TLA modified asphalt mixture were 1.1~1.8 times of that of ESSO asphalt mixture under each stress ratio.3) The fatigue performance of TLA modified asphalt mixture was analyzed. Test data were analyzed with stress-stain analytical method and energy consumption method respectively. Fatigue equation and fatigue curve of two fatigue models were obtained. Value of K in fatigue equation N f= Kσ?n of TLA modified asphalt mixture was 12.13~13.68 times of that of ESSO asphalt mixture, what proved that fatigue performance of TLA modified asphalt mixture was advanced remarkably, and it was excellent in fatigue performance. Besides, tests results of two kinds of fatigue tests were compared, what indicated that indirect tensile fatigue test undervalued the fatigue performance of TLA modified asphalt mixture greatly, so it was corrected and reasonable results was obtained.4) Because there are very great differences between indoor fatigue tests and actual road, various kinds of influence factors were considered. Fatigue life-span of TLA modified asphalt mixture was predicted according to the fatigue equations and predictive fatigue life-span equations were educed. Besides, the flexural tensile strength structure coefficient and the tensile strength structure coefficient were put forwarded to guide pavement design.In conclusion, fatigue performance of TLA modified asphalt mixture was researched with emphasis in the paper, and reasonable conclusions were obtained. It is expected that it can provide reasonable reference for the further applications of TLA modified asphalt mixture.