Preliminary Study on X-Ray Computed Tomography to Evaluate Voids in Porous Asphalt Concrete

2012 ◽  
Vol 174-177 ◽  
pp. 345-353 ◽  
Author(s):  
J. D. Lin ◽  
Ming Chin Yeh ◽  
Po Hsun Sung ◽  
R. H. Shiu

The study applies Computed Tomography technology to probe into the porous asphalt concrete and air voids content, and at the same time, try to qualify accessible voids and closed voids and to use the result to evaluate the performance of porous asphalt concrete. The nominal maximum aggregate of this study is 19.0mm. In order to adjust the image of the gray threshold, the void of PAC specimen was obtained by cut-and-try method with the mix design. After scanning through the PAC specimen, the self-innovated software is used to calculate the Va(%), accessible voids and closed voids. After careful calculation, it showed that the accessible voids are about 20.3%, and the closed voids are about 1.15%. Base on the study, it could analyze the effect of pore clogging in PAC with improved the durability and lifetime.

2015 ◽  
Vol 69 ◽  
pp. 451-456 ◽  
Author(s):  
I. Jerjen ◽  
L.D. Poulikakos ◽  
M. Plamondon ◽  
Ph. Schuetz ◽  
Th. Luethi ◽  
...  

2014 ◽  
Vol 911 ◽  
pp. 443-448 ◽  
Author(s):  
Abdul Hassan Norhidayah ◽  
Mohd Zul Hanif Mahmud ◽  
Putra Jaya Ramadhansyah

This study presents the characterisation of the air voids distribution for porous asphalt mixtures compacted using gyratory compactor. The distribution of voids content and voids shape within the porous asphalt were characterised for different nominal maximum aggregate size (NMAS) and specimen height. This is to evaluate the effect of different aggregate size composition and lift thickness on the air voids characteristics of the compacted porous asphalt. Two types of gradations were adopted i.e. Grading A (with NMAS=10 mm) and Grading B (with NMAS=14 mm) and they were fabricated for two different heights (50 and 100 mm). The internal structure was captured using X-ray Computed Tomography and image analysis techniques were used to process and analyse the images. It was found that mixture with coarse aggregate gradation produced larger void size with an elongated shape, which indicates voids connectivity within the mixture compared to fine gradation with more circular and smaller void size.For lift thickness, itacts differentlyfor different aggregate gradations. The specimen produced greater voids connectivity when the fine and coarse gradations were compacted at 100 mm and 50 mm respectively. These show that NMAS and lift thickness influence the mobility of the aggregate particles during compaction which affect the voids formation and determine the effectiveness of the compaction.


2020 ◽  
Vol 861 ◽  
pp. 414-420
Author(s):  
Ming Xi Liu ◽  
Jian Guang Xie ◽  
Zhan Qi Wang ◽  
Yan Ping Liu

The sound absorption performance of porous asphalt concrete (PAC) is inseparable from the sizes of voids, as different sizes of voids have different absorption effects on noise in different frequency bands. However, the relationship between the two is not clear. In this study, the equivalent diameter of voids was obtained by the proposed image segmentation algorithm based on the square area, then grey entropy method was used to analyze the effect of different equivalent diameter of voids on the sound absorption performance of PAC in the frequency range of traffic noise. The results show that with the increase of air voids, the peak and average sound absorption coefficient of PAC increase, the sound absorption performance of PAC is improved; and the sound absorption performance of PAC is mainly affected by the equivalent diameter of voids of 3-4mm.


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