Application of uniform design method on evaluation of internal factors to asphalt mixes fatigue life

A fractional factorial experimental design method named "uniform design" was applied on a four point bending experiment to evaluate the internal factors to fatigue performance of asphalt mixes. The internal factors considered in this study include asphalt type, asphalt content, air void, gradation, and the nominal maximum aggregate size. Then the regression models expressing the relationships between the internal factors and initial flexural stiffness and fatigue life were established. It is pointed that if the asphalt content increases by 1%, it will cause a 97% of increase in fatigue life; if the air void increases by 1%, it will cause a 4% decrease in fatigue life; if the penetration value of asphalt binder increases by 10, it will cause a 19% of increase in fatigue life. The results indicate that the number of fatigue test can be effectively reduced by using uniform design.