Evaluation of thermal behavior and high-temperature performances of asphalt mixture containing fly ash cenosphere

• Published in: Construction & building materials 2020-06, Vol.245, p.118429, Article 118429
• Main Authors: Yinfei, Du, Ling, Xu, Haibin, Deng, Deyi, Deng, Hao, Wu, Weidong, Liu
• Format: Article
• Language: English
• Subjects: Asphalt pavement; Fly ash cenosphere; Rutting resistance; Temperature reduction; Thermal conductivity
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2020.118429

•Fly ash cenosphere was used to prepared low-thermal-conductivity asphalt mixture.•The thermal conductivity of asphalt mixture reduced by 20.9%.•The maximum inner temperature reduction reached up to 2.4 °C.•Fly ash cenosphere had a negative effect on the shear strength of asphalt mixture.•Fly ash cenosphere had a negative effect on the rutting resistance of asphalt mixture. In order to prevent solar heat from transferring into asphalt pavement, fly ash cenosphere (FAC) was used to prepare low-thermal-conductivity asphalt mixtures (LTCMs) by replacing different volumes (i.e., 25%, 50%, 75% and 100%) of limestone mineral filler (LMF). Meanwhile, the shear strength and high-temperature performances of the above mixtures were also investigated. The results show that replacing LMF with FAC would increase the air voids content of LTCM, which, together with the hollow structure of FAC, led to the thermal conductivity of LTCM reducing by a maximum of 20.9%. According to an indoor irradiation test, the maximum inner temperature reduction reached up to 2.4 °C. However, the increased air voids content resulted in reduced mechanical and anti-rutting performances of LTCM. The shear strength reduced by 11.4% when LMF was completely replaced by FAC. The flow number of LTCM at the temperature of 60 °C reduced by a maximum of 65.9%. According to the dynamic modulus master curve (reference temperature of 21.1 °C) at the frequency of 5 Hz, the dynamic modulus of LTCM reduced by 24.5% when LMF was completely replaced by FAC. The cooled asphalt pavement and reduced rutting resistance of LTCM should be both considered in future studies to investigate the actual effect of FAC on the rutting performance of asphalt pavement.