水泥稳定碎石材料孔隙特性研究

Study on pore characteristics of cement stabilized macadam

摘要:

为研究水泥稳定碎石材料细观孔隙特性以及探究荷载作用时孔隙空间结构的变化过程,通过建立孔隙三维模型量化断面孔隙和三维孔隙,并转换为孔隙三维网络结构,提取孔隙配位数、孔隙体积、喉道长度等相关参数,研究参数随逐级荷载的变化规律,推演孔隙空间结构变化过程. 研究结果表明:量化的断面孔隙率与三维孔隙率能表征材料孔隙变化规律；m、n区域的峰值从12.10%、10.29%分别扩展到13.89%、13.41%,n区峰值分布区域跨11个层位,m、n区域波形变化较剧烈,孔隙细观结构变化明显；配位数均值由小于0.45突变为0.505,孔隙体积中小孔隙占据孔隙空间结构的80%,但随荷载增加孔隙体积会改变,喉道在逐级加载过程中,最大喉道长度增加近2 mm,喉道先负向演变后转为正向演变,荷载作用致使孔隙空间结构改变. 逐级荷载作用,孔隙细观结构和孔隙空间结构都发生剧烈变化,孔隙结构的剧烈变化导致材料内部结构改变,促使材料宏观破坏,因此材料宏观破坏与孔隙结构变化有着本质联系.

Abstract:

To study the micro pore characteristics of cement stabilized macadam and the change process of pore space structure under load, through the establishment of three-dimensional pore model to quantify the cross section pore and three-dimensional pore, and the conversion of three-dimensional pore network structure, the parameters such as pore coordination number, pore volume and throat length were extracted. The changing process of pore space structure was deduced by studying the changing rule of parameters with the step-by-step load. Results show that the quantitative porosity of cross section and three-dimensional porosity could characterize the pore change of materials. The peaks in m and n regions extended from 12.10% and 10.29% to 13.89% and 13.41%, the peak distribution region in n region spanned 11 layers. The waveforms in the m and n regions changed drastically and the micro structure of the pores changed significantly. The mean value of coordination number changed from less than 0.45 to 0.505 and the small pores in the pore volume occupied 80% of the pore space structure, but the pore volume changed with increasing load. During the gradual loading process of throat, the maximum throat length increased by nearly 2mm, the throat changed from negative to positive and the load changed the pore space structure. The change of pore microstructure and pore space structure resulted in the change of internal structure of materials and the macro failure of materials. Therefore, the macro failure of materials was essentially related to the change of pore structure.