Deteriorated hardened cement paste structure analyzed by XPS and 29Si NMR techniques

Abstract

In this report, X-ray photoelectron spectroscopy (XPS) and 29 Si-MAS-NMR was used for the evaluation of deteriorated hardened cement pastes. The deterioration by ammonium 2 nitrate solution was accompanied by changes in the pore structure as well as by structural changes in the C-S-H in the hardened cement paste. The CaO/SiO2 ratio of the C-S-H decreased with the progress of deterioration, there was also polymerization of the silicate in the C-S-H. It was confirmed that the degree of polymerization of silicate of the C-S-H in hardened cement paste can be determined by XPS. It was also shown that the polymerization depends on the structure of the C-S-H.Keywords: Calcium-Silicate-Hydrate (C-S-H)(B); Degradation(C); 29 Si NMR; X-ray photoelectron spectroscopy; CaO/SiO2 ratio 3

Effect of the paste–anode interface under impressed current cathodic protection in concrete structures

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