SAC13沥青混合料动态模量梯形梁试验研究

Experimental Study on Dynamic Modulus of SAC13 Asphalt Mixture with Trapezoid Beam Test

选用70~#基质沥青和SBS改性沥青设计了两种SAC13沥青混合料,使用梯形梁试验方法进行了动态模量试验研究,考察了沥青材料和荷载水平对动态模量及相位角的影响。基于时温等效原理,计算了主曲线移位因子,绘制了动态模量和相位角主曲线,分析了沥青混合料的动态力学性能和黏弹性能;利用非线性数值回归得到了动态模量三维主曲面。结果表明:主曲线能够较为全面地反映沥青混合料的动力学性能,通过改善沥青材料性能可以提高沥青混合料的路用性能;在两点加载模式下,随着应变水平的增加,动态模量减小,相位角增大;应变水平对动态模量和相位角的影响并非恒定,在高温(低频)时,应变水平的影响更加显著;超载会显著加速路面损坏,不仅仅因为荷载超过了路面承载力,而且因为荷载水平的增加降低了路面结构本身的力学性能。

70# matrix asphalt and SBS modified asphalt are chosen to design 2 SAC13 asphalt mixtures, on which trapezoid beam test is used to conduct the dynamic modulus test. The influences of asphalt and load level on dynamic modulus and phase angle are investigated. The Shift factor of master curved surface is calculated, the master curves of dynamic modulus and phase angle are plotted based on temperature-time equivalence principle, and the dynamic mechanical and viscoelastic property of the asphalt mixtures are analyzed. The 3D master curved surfaces are obtained by non-linear numeric regression. The result shows that （1） master curve can reflect the dynamic characteristics comprehensively, the road performance of asphalt mixture can he improved by enhancing asphalt property; （2） under two-point loading mode, as strain increases, dynamic modulus decreases while phase angle increases ; （3） the effect of strain level on dynamic modulus and phase angle is not constant, and the effect of strain level is more obvious at higher temperatures （lower loading frequencies） ; （4） overload can significantly accelerate pavement damage, not just because of the load exceeds the bearing capacity of pavement , but also the heavy load degrades the mechanical property of pavement structure.