Journal Published Online: 08 May 2019
Volume 48, Issue 6

Effect of Key Aggregate Morphology and Mold Modulus on the Spatial Distribution of Internal Air Voids in the Compacted Asphalt Mixture

CODEN: JTEVAB

Abstract

Air voids in asphalt mixtures have a significant effect on the mechanical performance and functional characteristics of asphalt pavement. The reasonable spatial distribution of internal air voids is not only necessary to ensure the road performance of asphalt pavement in the field but also helps to enhance the determination accuracy of a performance parameter of an asphalt mixture specimen in the laboratory. To improve the influence of uneven spatial distribution of internal air voids on the structure strength of asphalt mixture, especially the determination involved in the mechanical parameters of an asphalt mixture specimen in the laboratory, four different asphalt mixtures were fabricated by a Superpave Gyratory Compactor to research two influential factors: the morphological features of key 4.75-mm-diameter aggregates and the compaction mold modulus. The Aggregate Image Measurement System was employed to analyze the morphological features of the 4.75-mm-diameter aggregate, and 1 rubber gasket was pasted on the mold bottom plate and base plate to change the compaction mold modulus. The spatial distribution of internal air voids in the asphalt mixture specimen was captured through mathematical analysis on X-ray computed tomography scanning images. The results showed that 4.75-mm aggregates with higher sphericity can produce a more homogeneous spatial distribution of air voids in the compacted asphalt mixture specimen. Along the axial direction, the internal porosities of sublayers in the asphalt mixture specimen fluctuated from 4.5 to 15.6 %. The internal porosity in the asphalt mixture specimen increased with a decrease in the compaction mold modulus because part of compaction energy was absorbed by the rubber gasket, while the spatial distribution of internal air voids in the specimen compacted by low modulus mold was more homogeneous than that by a higher modulus mold. This research indicated that the spatial distribution of internal air voids in an asphalt mixture specimen can be optimized further with some appropriate controlling methods.

Author Information

Lei, Yong
School of Highway, Chang’an University, Xi’an, Shaanxi, China Department of Civil and Environmental Engineering, North Carolina A&T State University, Greensboro, NC, USA
Wang, Hainian
School of Highway, Chang’an University, Xi’an, Shaanxi, China
You, Zhanping
School of Highway, Chang’an University, Xi’an, Shaanxi, China Department of Civil and Environmental Engineering, Michigan Technological University, Houghton, MI, USA
Ji, Chuanjun
School of Highway, Chang’an University, Xi’an, Shaanxi, China
Dong, Shi
School of Highway, Chang’an University, Xi’an, Shaanxi, China
Yang, Xu
School of Highway, Chang’an University, Xi’an, Shaanxi, China Department of Civil Engineering, Monash University, Clayton, Vic, Australia
Gao, Junfeng
School of Highway, Chang’an University, Xi’an, Shaanxi, China Department of Civil and Environmental Engineering, Michigan Technological University, Houghton, MI, USA
Xiao, Jinkun
School of Highway, Chang’an University, Xi’an, Shaanxi, China
Pages: 19
Price: $25.00
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Stock #: JTE20180454
ISSN: 0090-3973
DOI: 10.1520/JTE20180454