磁铁矿粉对沥青混合料路用性能的影响研究

Research on the Influence of Magnetite Powder on Road Performance of Asphalt Mixture

为更好地促进磁铁矿粉在沥青混合料中的工程化应用,使用等体积替代方法将磁铁矿粉代替石灰岩矿粉掺入沥青混合料;借助车辙试验、小梁弯曲试验与冻融劈裂试验分析掺加磁铁矿粉对沥青混合料最佳油石比、高温稳定性、低温抗裂性与水稳定性的影响;并掺入消石灰改善其水稳定性。结果表明:沥青混合料的最佳油石比随磁铁矿粉掺量的增加而降低;适当的磁铁矿粉掺量有助于提升沥青混合料的高温稳定性与低温抗裂性,但会降低其水稳定性。综合考虑沥青混合料的路用性能,提出合理的填料改性沥青混合料方案为:80%磁铁矿粉+20%消石灰等体积替代石灰岩矿粉掺入沥青混合料中,相应的最佳油石比为4.47%。

In order to promote the application of magnetite powder in asphalt mixture,the equal volume substitution method is used to mix magnetite powder into asphalt mixture instead of limestone powder.The influence of magnetite powder on the optimum asphalt-stone ratio,high temperature stability,low temperature crack resistance and water stability of asphalt mixture are analyzed by rutting test,small beam bending test and freeze-thaw splitting test,and slaked lime is added to improve its water stability.The results show that the optimum whetstone ratio decreases with the increase of magnetite powder content.The appropriate volume of magnetite powder is helpful to improve the high temperature stability and low temperature crack resistance of asphalt mixture,but it will reduce its water stability.Considering the road performance of asphalt mixture,a reasonable packing modified asphalt mixture scheme is put forward as follows:80%magnetite powder and 20%hydrated lime are mixed into asphalt mixture to replace same volume limestone powder,and the corresponding optimal whetstone ratio is 4.47%.