基于X射线断层扫描的硬化水泥砂浆孔隙结构分析及表征

Investigation and Characterization of Meso Pore Structure of Hardened Cement Mortar by X-ray Computed Tomography

水泥砂浆是一种应用广泛的水泥基材料,其内部孔隙结构对其力学性能和耐久性有重要影响。水泥砂浆中孔隙结构复杂,传统方法都是通过实验获得统计平均的结果,无法从孔隙尺度分析孔隙结构对材料宏观力学性能及渗透性的影响,近些年发展起来的X射线断层扫描(X-CT)等成像技术为研究水泥砂浆孔隙结构提供了新的途径。利用X-CT获取水泥砂浆的孔隙图像,通过二维图像分析水泥砂浆的细观组分,根据形成原因与形貌对水泥砂浆内部孔隙(3.34μm以上的大孔和微裂缝)进行了分类;并重构了水泥砂浆的三维孔隙结构,探讨了水灰比对水泥砂浆孔隙率、孔隙体积以及孔径分布的影响,为分析水泥砂浆的力学性能与耐久性提供依据。

Cement mortar is one kind of the most commonly used cement-based materials.The pore structure of cement mortar,which is complex,has great effect to its mechanical properties and durability.Results obtained from the traditional methods through experiments are usually statistical average values which can’t reflect the effect of pore structure on the macroscopic mechanical properties and permeability of material from the pore scale.In recent years the development of X ray computed tomography(X-CT)has provided us a new approach to study the pore structure of cement mortar.The pore image of cement mortar was obtained by X-CT in this paper.The mesoscopic components of cement mortar were analyzed through two-dimensional image and the internal pores of cement mortar were classified according to the causes of formation and morphology where pores referred to macro pores and cracks above 3.34μm.Meanwhile the three-dimensional pore structure of cement mortar was reconstructed and the influence of water-cement ratio on the porosity,pore volume and pore size distribution of cement mortar was discussed,which provided a basis for analyzing the mechanical properties and durability of cement mortar.