填料类型和浸水时间对沥青混凝土力学性能影响分析

Effects of Filler Type and Soaking Time on Mechanical Properties of Asphalt Concrete

为探索填料类型和浸水时间对沥青混凝土力学性能的影响,使用相同配合比,分别配制以水泥和石灰石粉为填料1%孔隙率的沥青混凝土试件,并进行长期浸水的小梁弯曲试验、拉伸试验以及静力三轴试验。试验结果表明,随着浸水时间的延长,以水泥配制的沥青混凝土力学性能优于石灰石粉。其中,当浸泡时间由未浸水到浸泡2 250h时,水泥为填料的沥青混凝土抗拉强度由0.43 MPa上升至1.03 MPa,抗弯强度由1.42 MPa增加至4.06MPa,均持续上升;粘聚力增大351kPa、内摩擦角减小9.2°。以石灰石粉为填料时,抗拉强度由0.90 MPa减小至0.24MPa,抗弯强度由1.59MPa下降至0.84MPa,均持续下降;粘聚力增大203kPa、内摩擦角减小6.8°。水泥作填料的沥青混凝土随着浸水时间的增加应力不断增强,但材料适应变形的能力逐渐减弱;石灰石粉作填料的试件力学性能不断朝着劣势发展。

The experimental results show that the mechanical properties of asphalt concrete made of cement are better than those of limestone powder with the prolongation of soaking time.In order to explore the effect of filler type and soaking time on the mechanical properties of asphalt concrete,asphalt concrete specimens with1%porosity of cement and limestone powder were prepared respectively with the same mix ratio.And the specimens were used for the long-term trabecular bending test,tensile test and static triaxial test.The experimental results showed that with the prolongation of soaking time,the mechanical property of asphalt concrete prepared with cement was superior to the one prepared with limestone powder.Among them,when the soaking time was2250h,the tensile strength of asphalt concrete with cement as filler increased from0.43MPa to1.03MPa,and the bending strength increased from1.42MPa to4.06MPa.Both of the two strength continued to rise,and the cohesive force was increased by351kPa and the internal friction angle reduced by9.2°.When the limestone powder was used as filler,the tensile strength decreased from0.90MPa to0.24MPa,and the bending strength decreased from1.59MPa to0.84MPa.Both of the two strength continued to decline,and the cohesive force was increased by203kPa and the internal friction angle reduced by6.8°.With the increase of soaking time,the stress of asphalt concrete with cement as filler increased,but the ability of material to adapt to deformation diminished gradually,and the mechanical properties of limestone powder as filler continued to develop at a disadvantage.