Yue, Y;
(2015)
Application of Optical Fibre Raman Spectroscopy for Characterising Carbonation and Chloride Attack of Cementitious Materials.
Doctoral thesis , UCL (University College London).
Abstract
Carbonation and chloride attack are the main causes of the corrosion of rebars in concrete. In the past, attempts have been made to develop various sensors to monitor these deterioration mechanisms. However, amongst the most popular sensors, the Electrical Resistance Sensor cannot differentiate each individual deterioration mechanism, whilst the long term stability and the need for recalibration are the two main limitations of the Fibre Optical Sensor. The optical fibre Raman system, combining the fingerprint characterisation capacity of Raman spectroscopy and the light transmission capacity of optical fibres, offers the potential for monitoring the deterioration mechanisms in concrete. This thesis reports a detailed study to investigate the qualitative and quantitative working capacity of the optical fibre Raman system for characterising carbonation and chloride attack in cementitious materials. Two optical fibre Raman systems were developed to characterise the deterioration mechanisms in hardened PC and PFA/GGBS blended pastes, namely, a ‘coaxial’ optical fibre Raman system for characterising carbonation and a ‘transmission’ optical fibre Raman system for characterising chloride attack, respectively. The results showed that the calcium carbonate polymorphs (e.g., calcite, vaterite and aragonite) formed during the carbonation were successfully identified and the variation in the content of calcium carbonates over depth was also clearly differentiated and verified by bench-mounted Raman and Thermogravimetry (TG) analyses, demonstrating its good potential for establishing carbonation profiles. On the other hand, the chlorides and the chloride content were also successfully established and verified by bench-mounted Raman spectroscopy and chloride meter. The results from this thesis demonstrate a good potential for the optical fibre Raman system to be developed into a novel sensor system for monitoring the durability of concrete structures. However, the insufficient working capacity and the interferences from the addition of PFA and GGBS still need to be addressed in the future.
| Type: | Thesis (Doctoral) |
|---|---|
| Title: | Application of Optical Fibre Raman Spectroscopy for Characterising Carbonation and Chloride Attack of Cementitious Materials |
| Language: | English |
| UCL classification: | UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Civil, Environ and Geomatic Eng |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1464277 |
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