Microstructure Analysis of Modified Asphalt Mixtures under Freeze-Thaw Cycles Based on CT Scanning Technology

• Main Authors: Yafeng Gong, Haipeng Bi, Chunyu Liang, Shurong Wang
• Format: Article
• Language: English
• Published: MDPI AG 2018-11-01
• Series: Applied Sciences
• Subjects: computed tomography; modified asphalt mixture; freeze–thaw cycles; image processing technology; microstructure analysis
• Online Access: https://www.mdpi.com/2076-3417/8/11/2191

The modifiers NTC (nano-TiO₂/CaCO₃) and BF (basalt fiber) were adopted to modify a base matrix asphalt mixture. The base matrix asphalt mixture and three kinds of modified asphalt mixture under F⁻T (freeze⁻thaw) cycles were scanned by computed tomography. The air voids and morphological changes of asphalt mixture were summarized by image processing technology, and the development process of F⁻T damage to asphalt mixture was explained from a micro-view. The porosity of NTC-modified asphalt mixture changed little, and the void distribution between base matrix asphalt mixture and NTC-BF (nano-TiO₂/CaCO₃ and basalt fiber) composite modified asphalt mixture was more uniform. The macro-pores in the asphalt mixture under 15 F⁻T cycles began to connect gradually, and the pore characteristics also changed. The number and shape of the pores changed under 15 F⁻T cycles. According to the state characteristics, the change amplitude of the pore characteristics of matrix asphalt mixture and NTC-BF composite modified asphalt mixture were the most stable under F⁻T cycles.