dc.contributor.advisor | Wiik, Kjell | |
dc.contributor.advisor | De Weerdt, Klaartje | |
dc.contributor.advisor | Machner, Alisa | |
dc.contributor.author | Hemstad, Petter | |
dc.date.accessioned | 2019-09-11T10:50:15Z | |
dc.date.created | 2018-03-09 | |
dc.date.issued | 2018 | |
dc.identifier | ntnudaim:18355 | |
dc.identifier.uri | http://hdl.handle.net/11250/2615776 | |
dc.description.abstract | A new method for artificially leaching hydrated cement paste and studying how lowered pH in the pore solution affects chloride binding has been developed. Hydrated cement paste was exposed to a NaCl-solution before being acidified by adding small volumes of HCl in steps over several days, gradually lowering the pH. A pH-development curve was established, determining how the pH in the pore solution responded to increasing amounts of acid being added. The chloride binding of the cement paste as a function of the pH and free chloride concentration was then determined. For the range of pH from 12 to 13, decreasing pH increased chloride binding. At a pH of 11, the cement paste showed almost no chloride binding. The mechanisms of changes in chloride binding were investigated using TGA, XRD, SEM-EDS, ICP-MS and thermodynamic modelling. One of the main chloride binding phases, Friedel s salt, could not be detected with the applied techniques due to the cement paste being cured at 60 °C, therefore its influence could not be verified. Thermodynamic modelling does however confirm the possibility of Friedel s salt decomposing at pH 11. The increase in chloride binding from pH 13 to 12 is most likely related to the changes in the main hydrate phase C-S-H. The effect of pH on chloride binding should be accounted for in service life prediction models for concrete structures exposed to chlorides. | en |
dc.language | eng | |
dc.publisher | NTNU | |
dc.subject | Industriell kjemi og bioteknologi, Materialkjemi og energiteknologi | en |
dc.title | pH-dependence of chloride binding in ordinary Portland cement | en |
dc.type | Master thesis | en |
dc.source.pagenumber | 118 | |
dc.contributor.department | Norges teknisk-naturvitenskapelige universitet, Fakultet for naturvitenskap,Institutt for materialteknologi | nb_NO |
dc.date.embargoenddate | 10000-01-01 | |