Performance Evaluation of Airfield Rigid Apron Pavements Using HWD Testing, Back-Calculation, and FEA Correlation

Abstract: This paper presents a structural evaluation of rigid apron pavement slabs constructed in a major international airport. The assessment was initiated following variability in construction quality control/assurance (QC/QA) data, particularly flexural strength, and aimed to confirm compliance with the design intent for a 40-year pavement life.
The evaluation combined Heavy Weight Deflectometer (HWD) testing, back-calculation analysis, and Finite Element Analysis (FEA) to establish performance benchmarks and identify slabs requiring further review. A control group of 50 slabs meeting specification requirements was used to develop baseline deflection criteria. HWD testing was performed at two load levels (180 kN and 320 kN), and a preliminary allowable deflection threshold of 178 μm was established based on the control group and validated against similar large-scale studies.
Twenty-one slabs exceeded this threshold, with five also flagged for flexural strength non-conformance. These slabs underwent detailed analysis using FAA’s BAKFAA for modulus back-calculation and EverFE for FEA modeling. Results showed that all slabs, including the five under review, exhibited back-calculated PCC modulus values above the theoretical minimum corresponding to the design flexural strength of 5 MPa. FEA modeling predicted an allowable deflection range of 220–244 μm for slabs meeting design properties, and all five slabs fell within this range.
The study demonstrates the value of integrating HWD testing with mechanistic back-calculation and FEA to validate pavement performance, establish realistic acceptance criteria, and support long-term monitoring strategies. This approach provides a robust framework for managing quality variability in rigid airfield pavements while maintaining operational safety and design compliance.