水泥稳定碎石基层材料旋转冲刷性能及技术标准

Rotary scouring performance and technical standard of cement stabilized macadam base materials

摘要:

针对目前水泥稳定碎石基层材料抗冲刷试验难于操作和低效率等问题,开发一种水泥稳定碎石基层材料旋转冲刷试验设备,应用FLUENT软件对试件受到的冲刷力进行了数值模拟分析,得出不同冲刷工艺下试件冲刷面受到的冲刷力在8~50 kPa之间；根据不同试件浸水高度、冲刷频率和冲刷时间对试件冲刷效果的影响研究,提出了最佳旋转冲刷试验参数；研究了试件的无侧限抗压强度、空隙率和压实度对试件冲刷破坏的影响。结果表明:冲刷质量损失率随着无侧限抗压强度的增加呈线性减小,从抗冲刷角度而言,水泥稳定碎石的抗压强度不宜小于4.0 MPa,水泥剂量不宜小于4.5%；冲刷质量损失率随着空隙率的增加呈“U”形变化,抗冲刷最佳空隙率在2.5%~5.0%之间；压实度提高,试件的抗冲刷能力明显增加,最低压实度应大于98%；根据有限元模拟基层顶面脱空对路面结构疲劳寿命影响的分析结果,以沥青面层疲劳寿命降低幅度40%~60%为原则,提出了水泥稳定碎石抗冲刷技术标准。

Abstract:

In view of the problems of current scouring tests on cement stabilized macadam base (CSMB) materials such as difficult to operate and low efficiency, a rotary scouring test equipment for CSMB materials was developed. By using FLUENT software, the scouring force on specimens was analyzed in numerical simulation, and the scouring force on the surface of the specimens was about 8 to 50 kPa under different scouring processes. Based on the influence of different immersion heights, scouring frequencies, and scouring time on the specimens, the optimal rotary scouring test parameters were proposed. The influence of unconfined compressive strength, voidage and compaction degree on the scouring damage of specimens was analyzed. Results show that the scour mass loss rate was approximately linearly decreasing with the increase in the unconfined compressive strength. In terms of anti-scouring, the compressive strength of CSMB should not be less than 4.0 MPa, and the cement content should not be less than 4.5%. The scour mass loss rate changed in the form of “U” with the increase in voidage, and the optimal anti-scouring voidage was between 2.5% and 5.0%. With compaction degree enhanced, the scour resistance of the specimens increased, and the lowest compaction degree should be greater than 98%. According to the influence of top surface void of base layer on the fatigue life of pavement structure in finite element simulation, based on the principle that the fatigue life of asphalt layer reduced by 40% to 60%, the scour resistance technical standard of CSMB was put forward.