Recapitulation

• The fatigue and erosion damages are generally considered as primary structural factors which govern the concrete pavement design by mechanistic-empirical (M-E) approach. Cumulative damage principle is employed to evaluate the expected level of damage. Faulting and smoothness are the other considerations in the design.
• The design guidelines such as PCA (1994), Austroads (2004), NCHRP (2004), IRC:58 (2002) are based on M-E approach, whereas, the AASHTO (1993) approach of pavement design is purely empirical.
• While considering the cumulative fatigue damage (in M-E approach), the load stresses are primarily considered. The stresses due to temperature and/or moisture gradient are ignored in PCA (1994) and Austroads (2002) guidelines, but are considered in IRC:58 (2002) and NCHRP (2004) guidelines.