CIVIL ENGINEERING 365 ALL ABOUT CIVIL ENGINEERING



AbstractThe Federal Aviation Administration’s (FAA’s) pavement thickness design software, FAA Rigid and Flexible Iterative Elastic Layer Design (FAARFIELD) uses bottom-up fatigue cracking as the only failure criterion in its rigid pavement design procedure. However, top-down cracking has also been observed in two full-scale experimental studies under some circumstances; therefore, it should be included as one of the failure criteria in the analysis and design of rigid airfield pavement systems. In this study, FAA’s current rigid airfield pavement design methodology was reviewed and evaluated in great detail to better identify needs for improvements with respect to cracking failure models and to produce recommendations on how current design methodology could be improved. Critical mechanical loading and pavement response locations for top-down and bottom-up cracking failure modes were also investigated to seek identification of input scenarios where critical pavement responses at slab top are higher than those at slab bottom. The effect of temperature loading in determining which failure mode (top-down or bottom-up cracking) would be dominant in rigid airfield pavement failure was also studied. Slab thickness calculations were carried out using the same slab thickness determination steps as FAARFIELD design software (version 1.42) when top-down cracking and bottom-up cracking are specified as failure modes. Recommendations are made with respect to including the top-down cracking failure mode in rigid airfield pavement design.



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