矿物纤维改善沥青混合料高温稳定性研究

Investigation of High Temperature Stability of Asphalt Mixture Containing Mineral Fiber

分别采用动态模量试验、动态蠕变试验和车辙试验研究了玄武岩矿物纤维对沥青混合料的粘弹特性及高温稳定性的影响。研究结果表明,矿物纤维掺入后沥青混合料的动态模量和相位角具有相同的变化规律,且纤维的使用能提高沥青混合料的动态模量,表明玄武岩矿物纤维能明显提高沥青混合料的劲度,而60℃时沥青胶浆和沥青混合料的车辙因子增大。高温动态蠕变试验结果也表明,掺入矿物纤维后沥青混合料的流动值增大,达到流动值时循环荷载产生的应变和经历10 000次荷载作用后的应变均能得到大幅度的降低。与未掺矿物纤维相比,掺加0.4%矿物纤维后沥青混合料的动稳定度由5 869次/mm提高到7 656次/mm,同时车辙深度减小,表明矿物纤维能明显提高沥青混合料抵抗高温流动变形的能力。

Viscoelastic characteristics and high temperature stability of asphalt mixture with mineral fiber additives were investigated by various test methods, including dynamic modulus test, dynamic creep test and wheel rutting test. The test results indicate that （ 1 ） the dynamic modulus for asphalt mixtures increase when mineral fiber added, which imply that the stiffness of asphalt mixture can be enhanced by mineral fiber additives at high temperature; （2） the rutting parameters for asphalt mixtures increase at 60 ℃. Dynamic creep test for asphalt mixtures show that （1） the flow numbers of asphalt mixture with mineral fiber increases, furthermore, the mierostrains at flow number and after 10 000 loading cycles reduce significantly; （2） compared with the mixture without mineral fiber, the dynamic stability of asphalt mixture with 0.4% mineral fibers increases from 5 869 times/ram to 7 656 times/ram and the rutting depth decreases, which reveals that the resistance to high temperature permanent deformation for asphalt mixtures can be improved with mineral fibers.