Sustainable and resilient pavement infrastructure is critical for current economic and environmental challenges. In the past 10 years, the pavement infrastructure strongly supports the rapid development of the global social economy. New theories, new methods, new technologies and new materials related to pavement engineering are emerging. Deterioration of pavement infrastructure is a typical multi-physics problem. Because of actual coupled behaviors of traffic and environmental conditions, predictions of pavement service life become more and more complicated and require a deep knowledge of pavement material analysis. In order to summarize the current and determine the future research of pavement engineering, Journal of Traffic and Transportation Engineering (English Edition) has launched a review paper on the topic of “New innovations in pavement materials and engineering: A review on pavement engineering research 2021”. Based on the joint-effort of 43 scholars from 24 well-known universities in highway engineering, this review paper systematically analyzes the research status and future development direction of 5 major fields of pavement engineering in the world. The content includes asphalt binder performance and modeling, mixture performance and modeling of pavement materials, multi-scale mechanics, green and sustainable pavement, and intelligent pavement. Overall, this review paper is able to provide references and insights for researchers and engineers in the field of pavement engineering. ... Read more

Aggregate skeleton is the main load carrying part, which is important for the performance of asphalt mixture. Fine aggregate break the skeleton of coarse aggregate is defined as disruption. Based on the X-ray computed tomography and digital image process method, this paper aim to evaluate and verify the disruption in asphalt mixture, and then discuss the effect of disruption on the mesostructure and aggregate contact. Firstly, the aggregate classification and contact property calculation method are proposed. Based on the methods, the relation between disruption factor and contact property is analyzed. The results indicate that there is a strong linear trend between the distance of the main skeleton aggregate and disruption factor, and the disruption factor can well represent the expanding effect of disruption aggregate on the main skeleton aggregate. Additionally, higher disruption factor will leads to the decrease of the number of contact between the main skeleton aggregate and the increase of the contact number of the disruption aggregate. Further, if asphalt mixture has lower disruption factor, the internal contact between the main skeleton aggregates is closer. ... Read more

Gradation measurement is important for quality control of pavement construction. Computed tomography (CT) can capture the microstructure images of asphalt mixture. However, an accuracy digital image processing method should be developed. In this study, fuzzy network, multilevel threshold and morphological methods are utilized to reduce the noise, enhance the contrast and segment images. The 2D aggregate gradation obtained from the digital image segmentation procedure is transferred into 3D gradation by stereological method. The results show that fuzzy network can balance the noise reduction and contrast enhancement. The multilevel Otsu's threshold method can obtain the two thresholds automatically. The morphological processing and watershed transformation can fill the holes in the image and break the aggregate connections. By comparing the calculated gradation and the designed gradation, the image processing procedure proposed in this paper can be utilized to obtain the gradation information of AC, SMA and OGFC accurately and effectively. ... Read more