水泥砂浆细观结构代表性单元尺寸  

Representative Elementary Size of Mortar's Mesostructure

作　　者：戎志丹[1,2] 陈浩 高云 欧阳瀚梁 RONG Zhidan;CHEN Hao;GAO Yun;OUYANG Hanliang(College of Materials Science and Engineering,Southeast University,Nanjing 211189,China;Jiangsu Key Laboratory of Construction Materials,Nanjing 211189,China;Institute of Civil Engineering,School of Human Settlements and Civil Engineering,Xi'an Jiaotong University,Xi'an 712000,China)

机构地区：[1]东南大学材料科学与工程学院,南京211189 [2]江苏省土木工程材料重点实验室,南京211189 [3]西安交通大学人居环境与建筑工程学院,土木工程研究所,西安712000

出　　处：《硅酸盐学报》2024年第11期3537-3545,共9页Journal of The Chinese Ceramic Society

基　　金：国家重点研发计划(2019YFC1904902,2018YFC0705400);国家自然科学基金(51678142)。

摘　　要：水泥砂浆在细观尺度上呈现出典型的非均质结构,在做微观计算研究时,其代表性单元尺寸的恰当选取对于深入阐述结构—性能关系具有重要意义。制备了3种砂胶比(0.8、1.0和1.2)条件下的普通水泥砂浆,集料来源有天然砂和机制砂。首先利用计算机断层扫描技术获取水泥砂浆细观尺度的真实图像,在此基础上,结合数字图像处理与分析技术,采用平均占比函数、两点相关函数和径向分布函数分别从二维和三维角度计算集料在空间分布的统计特征,借以探究水泥砂浆细观结构的代表性单元尺寸。结果表明:制备砂浆的代表性单元尺寸与砂的体积分数无关,但受砂子种类的影响十分显著。对于天然砂砂浆,代表性单元尺寸为2.75~2.90 mm,约为其平均粒径的9倍;对于机制砂砂浆,代表性单元尺寸为3.1~3.2 mm,为其平均粒径的7倍左右。Introduction As a heterogeneous multiphase material,cement-based material has a significant correlation between its macroscopic properties and microstructure,and exhibits significant scale dependent characteristics.Representative element is defined as the smallest element that can represent the macroscopic property of multi-scale material.It is usually very difficult to study materials at the full scale.Selecting representative element of appropriate size can to some extent represent the overall characteristics,providing possibilities for microscopic calculations.Therefore,the appropriate selection of representative elementary size(RES)is of great significance for further elaborating the structure-performance relationship in micro computational research.For cement mortar,there has been considerable research on the RES of mortar’s microstructure of,but there is a lack of research on the RES of mortar’s mesostructure.Only scholar such as Winslow reported a value of 10-30 mm in early research with relatively single dependent indicator.In view of this,combined with digital image processing and analysis techniques,the statistical characteristics of the spatial distribution of aggregates were calculated from two-dimensional and three-dimensional perspectives by using the average proportion function,two-point correlation function and radial distribution function in this paper.Finally,the representative elementary size of the mortar’s mesostructure was explored.Methods Three types of cement mortars blended with cement,fly ash(FA),silica fume(SF)and sand were prepared in this research.The cement used was P·II52.5 in accordance with the relevant Chinese standard.The density of cement and FA are3.11 g/cm^(3)and 2.27 g/cm^(3),respectively.The specific surface area of FA and SF are 420 m^(2)/kg and 22000 m^(2)/kg,respectively.The fineness modulus of natural sands and manufactured sands are 1.66 and 2.25,respectively.Besides,one kind of polycarboxylic-type high performance water reducer was adopted as the superplasticiz

关 键 词：水泥砂浆 集料分布 代表性单元尺寸 计算机断层扫描技术 数字图像处理与分析 

分 类 号：TQ177.62[化学工程—硅酸盐工业]