混凝土界面过渡区物相微结构表征方法及演变规律浅析

混凝土界面微结构物相特征是影响混凝土宏观性能重要因素,其主要构成物相CH晶体、孔隙和C-S-H凝胶的表征方法及其演变规律一直是研究的重点和热点。总结了混凝土界面过渡区主要构成物相的表征方法及其优缺点,并建议采用SAXS结合MIP的方法研究界面在微观和细观尺度的孔结构、XRD方法研究界面区域CH的取向性、FTIR和NMR分别对界面C-S-H凝胶做定性和定量分析。分析发现水胶比减小、养护龄期增长、活性掺和料的掺入、渗透性较好和尺寸较大的骨料都会导致界面CH取向指数和孔隙率减小,界面C-S-H凝胶含量会随着养护龄期延长和活性掺和料掺入呈现出有规律的增长。

Method of Expressing Microstructure Phase Features and Evolution Law in Interracial Transition Zone of Concrete

Microstructure phase features in interfacial transition zone of concrete are important for concrete's macroscopic properties.Methods of representing CH crystal,pore and C-S-H gel and evolution law are always research hotspots.In this article,we summarized the representation methods for the main phases in interfacial transition zone of concrete and their advantages and disadvantages.We also recommend to employ SAXS in association with MIP method for studying the pore structure at microscopic and mesoscopic scales for the interface,XRD method for the orientation of CH in the interface region,FTIR for qualitative analysis on interface C-S-H gel and NMR for quantitative analysis on interface C-S-H gel.Results show that decreasing of water to binder ratio,increasing of curing age,blending of active admixture,good permeability and large size of aggregate all lead to the decreasing of porosity and CH orientation index in the interface.Moreover,the content of interface C-S-H gel increases with the growth of curing age and the blending of active admixtures.