# Dynamic Response Analysis of Airport Pavement under Impact Loading
## 1 Introduction  
The mechanical behavior of civil engineering structures or infrastructures under the most adverse conditions has been the focus of researchers for many years. The airport runway, as one of the most important infrastructures, is mainly used for normal aircraft takeoff, landing, and taxing, but is not sufficient to resist extreme loads such as rough impacts or explosions. Existing airport runways are not only subject to direct impacts caused by aircraft takeoff and landing, but also suffer from additional impacts caused by aircraft accidents. Simultaneously, runways can experience increased roughness during the course of operation caused by the load and other environmental factors over the long term, and the vibration and impact of aircraft cause wear and tear, endangering the safety of the runway in the process of aircraft takeoff, landing, and taxing. At present, the impact resistance of airport pavements is mainly evaluated using test measurements and simulation. The FWD (falling weight deflectometer), HWD (heavy weight deflectometer), and SHPB (split Hopkinson pressure bar) methods have been used to study the effect of impact loading on the road surface, and finite element software such as ANSYS and ABAQUS have been applied to simulate the impact process on the road surface and calculate its dynamic response. [PERSON] of the Civil Aviation University of China used FWD to measure the impact progress modulus of an airport pavement, combined with the ACN-PCN method, to reflect the structural load-bearing capacity of theairport pavement and ensure its operational safety [1]. [PERSON] calculated the parameters of the bending elasticity modulus, the equivalent modulus of elasticity of the foundation, and the thickness of the pavement based on FWD, and fitted the regression equation for the mechanical response of the airport pavement; the relative error between the FEM simulation and the regression equation was less than 2% [2]. [PERSON] shared practical experience with methods for measuring pavement bearing capacity, suggesting that the inclusion of the CBR obtained from impact testing when calculating PCN values would underestimate the potential for damage to asphalt concrete. In addition, the reliability of the values obtained from the tests is questionable, as the existing calculation methods are only meaningful under certain assumptions and limitations, and there is no referable calibration procedure between the methods [3]. [PERSON] investigated the factors affecting the dynamic deflection and velocity response of a concrete airport pavement under impact loading. The results showed that the thickness and dimensions of the slab were the main factors influencing the variation in the deflection, and the modulus of the foundation reaction had a greater influence on the velocity response. On the basis of this, a non-linear relationship between the thickness of the slab and the maximum deflection has been proposed [4]. [PERSON] analyzed the ability of different software programs to process drop hammer bending instrument data and verified the accuracy of the inversion results by comparing the inversion data with indoor test results. The results suggest that the EVERCALC processing software has higher precision and accuracy [5]. [PERSON] calculated the required response values for the load-bearing capacity of airport pavements using HWD or FWD. This helps airport managers to assess the performance of airport pavements to ensure safe operation [6]. [PERSON] investigated the effect of impact loading on the damage level and mechanical response of recycled aggregate reinforced concrete on airport pavements with different thicknesses and reinforcement ratios using FWD. On the basis of this study, optimization recommendations were proposed for the promotion of the application of recycled aggregate concrete in the field of road construction [7].