Improved rolling dynamic deflectometer testing and analysis procedures



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A three-part study was undertaken to further improve the Rolling Dynamic Deflectometer (RDD). The first part involved the development of second-generation rolling sensors. Key benefits of this new rolling sensor are: (1) increased testing speed from 1 to 3 mph (1.6 to 4.8 km/hr), and (2) reduced the level of rolling noise during RDD measurements. With this rolling sensor, the RDD can collect more deflection measurements at a speed of 3 mph (4.8 km/hr). Field trials using the first- and secondgeneration rolling sensors on both flexible and rigid pavements were performed to evaluate the performance of the second-generation rolling sensor. The second part of this study involved improving the understanding of rolling noise collected on highway and airport pavements. This effort was accomplished by analyzing RDD data that were collected over the last seven years. A total of 46 different highway and airport test sites were evaluated to systematically investigate the effects of deflection levels, pavement surface roughnesses, and testing speeds on the rolling noise characteristics. These findings allow the development of a rolling noise envelope to estimate the rolling noise components. The third part of this study involved improving the data analysis method for RDD testing. An alternative data analysis method was developed. This new analysis method produces results that are comparable to the existing analysis method. Key benefits of this analysis method that were not previously available are: (1) analysis of the rolling noise characteristics, (2) design of individual digital filters for a particular set of RDD measurements, and (3) filtering of the RDD data at the operating frequency without performing the amplitude demodulation procedure. Finally, a Windows-based computer software, called WinRDD, was developed to automate the data analysis method presented in this dissertation.