Reconsidering the strength of concrete pavements

ABSTRACT

Concrete pavements develop cracks with the accumulation of fatigue damage caused by the combined effect of vehicular and environmental loadings. In Mechanistic-Empirical (ME) design, the ratio of stresses to some measure of strength is used to evaluate incremental damage, which is then related to cracking. Typically, this measure is the Modulus of Rupture (MOR) of a beam made of the same material. The flexural strength is also known to vary with the thickness of the beam. However, the variation of flexural strength due the presence of eigenstresses from temperature or moisture distributions has not received sufficient attention. A non-linear fracture mechanics model demonstrated that the thickness-adjusted flexural strength can also be used for characterising the maximum elastic stress under a linear temperature distribution. However, under a non-linear temperature distribution, the material may sustain a higher or lower maximum elastic stress than the flexural strength. To model this, a practical analytical expression for the apparent flexural strength was derived and showed excellent agreement with numerical simulations as well as with a model based on equivalent elastic deformation energy. The model was used to show that the fatigue capacity under a typical axle load varies with various non-linear temperature distributions.

KEYWORDS:

• Non-linear fracture mechanics
• size effect model
• eigenstresses
• flexural strength
• non-linear temperature distribution
• modulus of rupture

Acknowledgements

Dr. Sen’s postdoctoral work was supported by funding from the Anthony Gill Endowed Chair at the University of Pittsburgh, United States. The authors would like to thank Mr. Haoran Li.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data used in this study may be made available upon reasonable request to the corresponding author.