伦敦大学学院UCL 讲席教授Yun Bai讲座
Title : Raman Spectroscopic Investigation of Friedel's Salt
讲座时间： 2020年1月13日 （周一）上午 9:10-11:10
Time :Jan 13th 2020, 9:10-11:10 am
地 点： 土木与交通工程学院B401
Location : B401, College of Civil and Transportation Engineering
Yun Bai伦敦大学学院（UCL）土木工程材料讲席教授（chair professor），AIM组学术带头人。近三十年来，致力于建筑材料和建筑废弃物的工程化应用，在其研究领域核废料废弃物固化、微波养护技术在混凝土中的应用领域具有较高的声誉。
Friedel's salt (FS) forms upon chloride binding in monosulphoaluminate (AFm) phase. This removes chlorides from the pore solution, hence, delays the initiation of steel bar corrosion. Understanding the chloride binding, in particular, characterizing and monitoring the formation and the status of FS is of great importance to the durability of reinforced concrete structures.
Although characterization techniques such as NMR, XRD, TG can be used to analyze FS, they all suffer different issues. Since 1970’s, Raman spectroscopy has attracted increasing attentions worldwide in analysing various phases in cement and concrete area due to its fingerprint characterisation capacity based on the measurement of the vibrational spectra of analytes and, thus, offers a potential for investigating FS.
In this presentation a recent work carried out in the Advanced and Innovative Materials (AIM) Group at University College London on using Raman spectroscopy to characterize FS is to be reported. Both the synthesised pure FS and the FS formed in a Portland cement (PC) paste powder were analyzed by a bench mounted Raman spectrometer. The results revealed the full Raman spectra of pure FS between 200 and 4000 cm-1, including the featured Raman bands at 534/ 568 cm-1 and 783 cm-1 which correspond to the Al OH stretching and bending vibration of FS respectively. Furthermore, similar Raman bands of FS were identified in PC paste sample subjected to accelerated chloride attack, further confirming the potential of Raman spectroscopy for distinguishing FS in cementitious materials.