# Runway Pavement Structural Analysis Using Remote Laser Doppler Vibrometers
## 5 Conclusions  
This research introduces a novel pavement deflection testing method utilizing a Remote Laser Doppler Vibrometer (RLDV). This study presents a design scheme for runway deflection tests based on RLDV and proposes compensation methodologies for addressing small angle measurement and fixed-end beam vibration issues inherent in the design scheme. The precision of these compensation methodologies has been experimentally verified and optimized. Lastly, a regression analysis models the relationship between RLDV and Heavy Weight Deflectometer (HWD) test data. We draw the following conclusions:  
1. The proposed deflection test scheme satisfies the non-stop, non-contact testing requirements at airports.
2. The employed angle compensation and vibration compensation methodologies have demonstrated effective data processing. The vibration compensation method reduces the effect of fixed beam vibration on detection from 12.76% to 6.48%.
3. There is a strong correlation between the RLDV and HWD test results, evidenced by an \(R^{2}\) value of 0.94. This suggests that RLDV holds significant potential for intelligent detection of airport runway structural performance.  
The experiments in this study have been carried out on indoor or outdoor cement concrete slabs. The RLDV has not yet been successfully applied to the field structural evaluation of airport runways. Therefore, it is not possible to assess the effect of aircraft type, speed, moisture, special weather conditions, etc., on vibration signal collection and the RLDV test.  
Future enhancements will center around the acquisition of more data to refine the test scheme design and the associated compensation methodologies. Application of this test scheme to evaluate the structural performance of airport runways constitutes the forthcoming step in our research endeavor. The future work plan is as follows:  
1. Apply the RLDV to airport runway structural performance field tests and analyze the effects of aircraft, load, environment, and other factors on vibration signals and RLDV tests.
2. Optimize the applied compensation method using extensive field experimental data.
3. Establish a systematic measurement and evaluation system to provide a convenient and efficient method for evaluating pavement performance, including RLDV installation, data processing, performance analysis, etc.  
Figure 12: Correlation analysis of RLDV and HWD.  
**Author Contributions:** Conceptualization, G.Y., Y.T. and X.Z.; methodology, Y.T. and X.Z.; software, G.Y. and L.L.; validation, G.Y., X.Z. and Y.T.; formal analysis, Y.T. and X.Z.; investigation, X.Z. and L.L.; resources, Y.T.; data curation, X.Z.; writing--original draft preparation, X.Z.; writing--review and editing, X.Z.; visualization, X.Z. and L.L.; supervision, G.Y.; project administration, G.Y.; funding acquisition, Y.T. All authors have read and agreed to the published version of the manuscript.  
**Funding:** Supported by the Fundamental Research Funds for the Central Universities.  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The data presented in this study are available on request from the corresponding author.  
**Acknowledgments:** The authors acknowledge Sunny Optical Intelligence Corporation for the technical support for the installation and operation of RLDV during the experiment.  
**Conflicts of Interest:** The authors declare no conflict of interest.