基于三维XCT对碳化引起水泥砂浆内部缺陷改变的测试和分析(英文)  

Investigation on Carbonation Induced Meso-Defects Changes of Cement Mortar Using 3D X-Ray Computed Tomography

作　　者：韩建德[1] 潘钢华[1] 孙伟[1] 

机构地区：[1]东南大学材料科学与工程学院,江苏省土木工程材料重点实验室,南京211189

出　　处：《硅酸盐学报》2011年第1期75-79,共5页Journal of The Chinese Ceramic Society

基　　金：国家“973”计划“环境友好现代混凝土的基础研究”(2009-CB623200)

摘　　要：为了揭示碳化反应对水泥砂浆内部缺陷分布的影响规律,采用三维XCT(X-ray computed tomography)对碳化前后的水泥砂浆的三维内部缺陷体积分数和缺陷尺度分布进行了定量分析。通过XCT的配套软件VG Studio MAX 2.0对水泥砂浆内部缺陷的投影进行三维重构,并通过配套的三维缺陷分析模块软件从三维图像中提取出水泥砂浆内部缺陷的体积分数和尺度分布。结果表明:三维缺陷尺寸范围为0.03～5.5 mm3,碳化前后的水泥砂浆内部缺陷体积分数分别为2.79%和1.86%。体积小的缺陷减小的比例更大,特别在0.03～0.1 mm3的缺陷体积减小的比例最大。主要原因是水泥砂浆中的氢氧化钙和CSH凝胶碳化反应后生成碳酸钙和水,相同摩尔质量的碳酸钙的体积比氢氧化钙和CSH凝胶都要大,碳酸钙和水填堵并细化了原来的缺陷,导致碳化后水泥砂浆内部缺陷体积分数减小。In order to investigate the defect changes of cement mortar due to carbonation,X-ray computed tomography（XCT） was employed to quantitatively analyze three dimensional（3D） meso-defect volume distribution changes of cement mortar before and after carbonation.The high-resolution 3D images of microstructures and filtered defects were reconstructed by XCT VG Studio MAX 2.0 software.The meso-defect volume fractions and size distribution were analyzed based on 3D images via add-on modules of 3D defect analysis.The results indicate that 3D meso-defect volume distributions are from 0.03 to 5.5 mm3,and the meso-defect volume fractions before and after carbonation are 2.79% and 1.86%,respectively.After carbonation,the smaller defects decreased signifi-cantly,compared to the bigger defects,in particular between 0.03–0.1 mm3.The main reason was calcium carbonate and water,which were generated by carbonation.The molar volume of calcium carbonate was larger than that of calcium hydroxide and CSH gel.Therefore,the new generated calcium carbonate and water could fill and refine some defects.

关 键 词：XCT 水泥砂浆 碳化反应 微结构改变 三维缺陷分析 

分 类 号：TU522.07[建筑科学—建筑技术科学]