太赫兹技术在水泥基材料研究中的应用

Applications of Terahertz Technology in Cement-based Materials

本文介绍了太赫兹波的特性以及太赫兹技术的工作原理及其应用,重点介绍了太赫兹时域光谱技术和太赫兹成像技术在水泥水化过程、水泥基材料的微观结构检测和水泥基材料耐久性能三方面的研究进展。利用太赫兹光谱技术可跟踪硅酸三钙、硅酸二钙以及主要水化产物水化硅酸钙、氢氧化钙在水化过程中的变化情况;利用水分对太赫兹波强烈吸收的特性,能够得到水泥基材料的裂缝开展和内部缺陷信息,也可以测得水泥基材料内部氯离子的含量和分布情况。通过太赫兹时域光谱技术还可以获取水泥净浆的介电常数,并发现其随孔结构参数(孔隙率、最可几孔径、总孔体积和孔表面积)的增大而线性减小。利用Bruggeman有效介质模型对试验结果进行验证,证实使用太赫兹时域光谱技术来研究水泥基材料的孔结构是可行的。

This study introduces the characteristics of terahertz wave,working principle and applications of terahertz technology.A state-of-art review of terahertz technology researches is conducted,including cement hydration process,microstructure and durability of cement-based materials.Terahertz technology can be used to analyze contents of C_(3)S,C_(2)S,C-S-H,and Ca(OH)_(2) during hydration.The crack development and internal defects of cement-based materials can be obtained by utilizing strong absorption of terahertz waves by moisture.Terahertz technology can also measure the content of chloride ions and its distribution in cement-based materials.In current study,terahertz time-domain spectroscopy is tested to extract the dielectric constant of cement paste.It is found that the dielectric constant decreases linearly with the increase of pore structure parameters(porosity,most-probable pore size,total pore volume,and pore surface area).The Bruggeman effective medium model is used to verify the test results.It is proved feasible to study the pore structure of cement-based materials by using terahertz time-domain spectroscopy.