Assessment of Freeze-Thaw Cycles Impact on Flexural Tensile Characteristics of Asphalt Mixture in Cold Regions

Low average temperature, large temperature difference, and continual freeze-thaw cycles have significant impacts on mechanical property of asphalt pavement. Bending test was applied to illustrate the mixtures’ flexural tensile properties under freeze-thaw (F-T) conditions. Experiment results showed that the flexural tensile strength and strain declined as F-T cycles increased; the deterioration of flexural tensile properties decreased sharply during initial F-T cycles but turned smooth after 15–21 F-T cycles. ANOVA showed that F-T cycles, asphalt-aggregate ratio, and gradation had obvious influence on flexural tensile characteristics. Flexural characteristics of AC-13 behaved better than the other gradations. It turned out that the mixtures’ low-temperature bending characteristics were improved when 5.5% optimum asphalt-aggregation ratio or slightly larger AC-13 gradation was applied.