Normalization Of Fatigue Characteristics Of High Modulus Asphalt Mixtures Under Different Stress States

As an effective and economical new pavement material,high-modulus asphalt mixture can significantly improve the performance of anti-rutting and water damage,and improve the service life and overall bearing capacity of pavement,so it has become the focus of current road workers.However,in the previous studies on the strength and fatigue parameters of high-modulus asphalt mixtures,different anti-fatigue effects were obtained only by adding different modifiers.Or the fatigue properties of high-modulus asphalt mixtures are determined only by one loading mode,and the differences in fatigue test results under different loading modes are ignored,which artificially leads to the fatigue resistance design of high-modulus asphalt pavement.non-unique and unscientific.In this paper,fatigue tests under different loading modes(direct tension,indirect tension,and uniaxial compression)are carried out on high-modulus asphalt mixtures to study the effect of stress state on fatigue performance.Analysis of the traditional S-N fatigue equation found that the traditional S-N fatigue equation did not take into account the influence of loading mode,specimen size and shape.In this paper,a new fatigue characteristic analysis method is adopted to achieve a unified characterization of the fatigue performance of high-modulus asphalt mixtures under different stress states,thereby improving the fatigue resistance design of high-modulus asphalt pavement and providing high-modulus asphalt pavement construction.theoretical guidance.In this paper,the strength test of high-modulus asphalt mixture under different loading modes and temperatures is firstly completed,and the variation law of strength at different temperatures and stress states with loading rate is revealed.The temperature has a significant effect on the strength,and the strength results are also affected by the loading mode.Through the relationship between the loading rate ratio and the strength ratio,a unified strength characterization model of different loading modes was established at three temperatures.The temperature parameters were considered,and finally the strength normalization equation of high-modulus asphalt mixture under different temperatures and loading modes was established.The fatigue test results were analyzed,and the limitations of the traditional S-N fatigue equation were summarized.According to the Desai strength yield surface theory,fatigue stress paths and fatigue stress ratios(ratio of effective stresses)were determined for high modulus asphalt mixes under three-dimensional stress conditions.The effective stress ratio and fatigue life are fitted linearly in a double logarithmic co-ordinate system,resulting in a fatigue normalised model for high modulus asphalt mixtures in a three-dimensional stress state.The results of this paper eliminate the variability of fatigue test results due to specimen size and loading patterns,effectively improving the completeness of structural design of high modulus asphalt pavements.