Probabilistic Assessment of the Fatigue Performance of Crumb Rubber Concrete Pavement: Fatigue Model Development and Reliability Assessment

Recycled postconsumer tyres show potential to be used as an alternative to natural aggregate in pavement concrete where fatigue performance is crucial. This paper presents four fatigue models for crumb rubber concrete, considering probabilistic concepts and statistical analysis. The probability of survival was incorporated in the form of McCall’s model, enabling it to serve as a user input for pavement design. A two-parameter Weibull distribution function is used to statistically analyze the fatigue life. Reliability assessment is carried out to predict the fatigue failure of pavement using the developed models. An illustrative example is presented, accompanied by a sensitivity analysis identifying the most influential variables for pavement fatigue failure. The reliability index and corresponding failure probability of pavement under different axle groups were determined. This study shows that the fatigue models developed based on plain concrete underestimate the fatigue life of crumb rubber concrete, emphasizing the necessity of updating the models for innovative materials. Additionally, it is found that the concrete flexural strength and axle group loads are the dominant variables influencing fatigue failure. It also highlights that the probability distributions of input variables can affect the sensitivity analysis results.