دانلود رایگان مقاله ارزیابی آسفالت تغییر از خالی از هوا بتن آسفالتی از طریق داده آرایه آنتن GPR

Abstract

Air void content is one of the most important characteristics of in-place asphalt concrete, substantially affecting early deterioration and long term performance. Destructive measures at limited locations, such as coring, are typically conducted as part of the air-void content evaluation after the pavement has been fully constructed. In this paper, use of an air coupled step-frequency array system for nondestructive assessment of air-void variability is explored. The dielectric properties of the asphalt were determined from the asphalt surface reflection amplitude of all 21 adjacent transmitting and receiving pairs of the array and related to air void content through plotting of dielectric changes with core measured air void content. This approach is an extension of the procedure developed for a single bistatic antenna pair determining properties within top millimeters of the asphalt surface. While cores provide information concerning bulk properties across the depth, the proposed method with an array system provides an opportunity for increased lateral coverage. The case study demonstrated good repeatability and correspondence with core measured air void content. The array-based method improves the coverage and productivity of the measurements, making it an attractive alternative to current state-of-the-practice procedures.

4. Conclusions

Improved asphalt concrete air void characterization was demonstrated in this case study by the use of a 21 antenna GPR array system on an in-service pavement. Using the reflection amplitude, a dielectric map of the tested area was obtained. Analysis of the dielectric map allowed for logical selection of core locations to develop a relationship between dielectric values and air void content. While more field trials with additional cores are necessary for full implementation, initial analysis of this type of application shows the potential to provide benefits to road owners such as improved pavement quality and durability by providing complete coverage. The ability to quickly identify air void excesses and deficiencies after rolling compaction has been completed and the surface has dried sufficiently, offers an opportunity to implement corrective measures immediately for new construction projects.