Study On Reliability Evaluation Of Asphalt Pavement Based On Modulus Degradation

Reliability, which plays a key role in quality control of engineering, has great application value in many engineering fields. As one of the core indicators in life cycle theory, reliability is expected to scientifically evaluate health status on the pavement. However, reliability study in the field of asphalt pavement only takes decades, and thus the related research methods need to be improved. In addition, with the development of the various technologies of asphalt pavement, the current reliability theory in asphalt pavement has many unreasonable places, so basic idea and future development of the reliability for asphalt pavement are in dire need of being re-examined. For the above, the idea evaluating the reliability of the pavement based on material properties is proposed in this paper. The main research contents as follows:Firstly, this paper analyzed the current reliability probability analysis models for asphalt pavement structure, putting forward the shortcomings in the existing models. Three kinds of typical methods of reliability calculation were elaborated from different angles. Reliability analysis process based on modulus degradation was established based on overall evaluation thinking.Secondly, the normalized modulus threshold of semi-rigid base material was analyzed. Based on nonlinear fatigue damage and Weibull distribution, modulus degradation models of semi-rigid base material were established, which was validated by experimental data.Thirdly, reliability models based on modulus degradation were established base on modulus degradation models of semi-rigid base material. Common methods of reliability calculation were comparatively analyzed. Taking into all the factors considers, Monte Carlo method was selected for calculation. Reliability analysis process based on Monte Carlo( MC) method was established, and its Matlab calculation procedure is compiled. Taking cement stabilized macadam for example, the functions corresponding to different stress levels(0.70 and 0.60) were established. Reliability of cement stabilized macadam was calculated when any number of load cycle. The relationship between modulus degradation and reliability was analyzed by transforming the change of modulus and reliability into the process along with the change of load cycle times.Finally, combining with the existing dynamic modulus degradation model of asphalt mixture, modulus degradation model representing the relationship between normalized modulus and load cycle times was put forward. Meanwhile, normalized modulus thresholds were analyzed on the fatigue tests. The laws of evolution for the reliability of asphalt mixture were achieved on the fatigue tests using Monte Carlo method.