Experimental investigation on bonding property of asphalt-aggregate interface under the actions of salt immersion and freeze-thaw cycles

• Published in: Construction & building materials 2019-05, Vol.206, p.590-599
• Main Authors: Guo, Qinglin, Li, Guangyao, Gao, Ying, Wang, Keyi, Dong, Zizhen, Liu, Fuchun, Zhu, Han
• Format: Article
• Language: English
• Subjects: Asphalt concrete; Asphalt-aggregate; Freeze-thaw cycles; Interface bonding properties; Methods; Pull-off tensile test; Salt solution immersion; Snow removal
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2019.02.094

•Effects of salt and freeze-thaw cycles on asphalt-aggregate interface were investigated.•A power model was suitable for estimating the coupled effects of different factors.•DIP technology was employed to identify the cohesive and adhesive failure areas. Snowmelt salts and deicing additives which are used to remove the snow/ice in winter make the pavement experience diverse and complex actions such as freeze-thaw (F-T) cycles and salt immersion. Meanwhile, interface damage of asphalt-aggregate is a major reason for the decay of mixture properties. So, the interface properties under the impacts of snowmelt salt and F-T cycles were investigated in this paper. Three factors including salt concentration, soaking time and F-T cycles were considered based on the service condition of the pavement. ‘Sandwich’ specimens of asphalt-aggregate were prepared in the laboratory. Also, pull-off tensile test was conducted by universal test machine. Digital image processing technology was employed to analyze the interface failure mode. Results indicated that the selected three factors presented significant effects on moisture absorption and pull-off tensile strength (POTS). All of the POTS at low, medium and high temperatures decreased after conditioning. And the pull-off tensile strength loss (POTSL) after salt solution soaking and F-T cycles were all higher than the pure water soaking one. The power model can be used to describe the composite damage degree imposed by different factors. The coupling actions of salt immersion and F-T cycles would induce the failure mode variety. Adhesive failure was prone to occur at low temperature under the condition of low salt concentration and F-T cycles. Erosion effect of high concentration solution would induce the adhesive failure at medium temperature.