沥青混合料在冻融循环作用下的弯拉特性

通过沥青混合料在冻融循环作用下的弯曲试验,分析了冻融循环次数、油石比、级配组成对混合料弯拉特性的影响。试验结果表明:随着冻融循环次数的增多,沥青混合料的弯拉强度、弯拉应变、劲度模量均呈减小趋势。油石比、级配组成对弯拉特性有明显影响,随着油石比的增大,冻融循环作用对沥青混合料弯拉特性的影响减小,AC-13混合料的弯拉特性优于其他两种级配。在青藏高原寒冷地区采用AC-13的沥青混合料、油石比为5.5%或适当增加油石比可以提高沥青混合料在冻融循环作用下的低温弯曲特性。

Flexural tensile characteristics of asphalt mixture under freeze-thaw cycles

By bending test of asphalt mixture under freeze-thaw conditions,the influences of freeze-thaw cycles,asphalt-aggregate ratio and gradation composition on the flexural characteristics of asphalt mixture were investigated.Experiment results show that,the flexural tensile strength,the flexural-tensile strain and the stiffness modulus of asphalt mixture decrease with the increase in the number of freeze-thaw cycles.Obvious influences of the asphalt-aggregate ratio and gradation composition on the flexural characteristics were observed.As the asphalt-aggregate ratio increases,the influence of freeze-thaw cycles on the flexural characteristics decreases.The flexural characteristics of AC-13 mixture are better than that of other two gradations.It is shown that applying AC-13 mixture with 5.5% OAC or higher can improve low temperature flexural characteristics of the asphalt mixture under freeze-thaw cycle condition.