Characterization of asphalt mixture using X-ray computed tomography scan technique after freeze-thaw cycle and microwave heating. (5th September 2022)

• Record Type: Journal Article
• Authors: Zhang, Fan; Cao, Yangsen; Sha, Aimin; Lou, Baowen; Song, Ruimeng; Hu, Xinkang
• Is Part Of: Construction & building materials. Volume 346(2022)
• Publication Date: 2022-09-05
• Subjects: Microwave heating moment -- X-ray computed tomography -- F-T cycles -- Self-healing -- Internal pore structure; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2022.128435
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Recommend the optimum healing moment of different asphalt mixtures suffering from moisture damage. HEL and SRL are introduced to compare the self-healing properties of different asphalt mixtures. There are three moisture damage and microwave healing modes of asphalt mixtures on pores. Valid pores and invalid pores are proposed to characterize the internal pores of asphalt mixtures. The self-healing properties and characterization of different asphalt mixtures are compared. Abstract: Microwave heating technology could heal micro-cracks caused by freeze-thaw (F-T) cyclic damage. The main objectives were to recommend the optimum heating moment and evaluate the difference between two typical mixtures during F-T cycle and microwave heating based on microstructure. To this end, cyclic F-T split tests and microwave heating tests were conducted to determine the best heating moment. In addition, the internal structure was scanned using X-ray computed tomography and evaluated using digital image processing. The results indicated that the optimum timing to heal two different asphalt mixtures (AC-13 and OGFC-13) occurred when the degrees of moisture damage were 39.8% and 42.4%, respectively. AC-13 exhibited better heating uniformity, and OGFC-13 exhibited better heating transferring. Moreover, F-T damage and microwave heating could change the internal structure: three types of moisture damage were seen in the voids: pore generation, connections, and expansion; pore number, porosity, pore area, and equivalent diameter first increased after the F-T cycles and then decreased after microwave heating, but the effect for OGFC-13 was more obvious; The F-T cycles mainly increased the number of valid pores, and microwave healing mainly increased the number of invalid pores; The damage and healing process of AC-13 and OGFC-13 mainly occurred on the 0.15–1.18 mm and 0.15–4.75 mm pores. This research could contribute to maintenance cost savings and revelation of F-T damage and microwave healing mechanism.