Effect of alkalis on fresh C–S–H gels. FTIR analysis

• Published in: Cement and concrete research Vol. 39; no. 3; pp. 147 - 153
• Main Authors: García Lodeiro, I., Macphee, D.E., Palomo, A., Fernández-Jiménez, A.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-03-2009; Elsevier
• Subjects: Alkalis; Applied sciences; Buildings. Public works; Calcium–Silicate–Hydrate (C–S–H); Cement concrete constituents; Cements; Exact sciences and technology; Materials; Properties and test methods; Properties of anhydrous and hydrated cement, test methods; Spectroscopy; Alkalis; Spectroscopy; Calcium–Silicate–Hydrate (C–S–H); Alkali; CSH phase; Experimental result; Calcium-Silicate-Hydrate (C-S-H); Concentration; Fourier-transformed infrared spectrometry; Experimental study; Portland cement; Structure composition relationship
• ISSN: 0008-8846; 1873-3948
• DOI: 10.1016/j.cemconres.2009.01.003

The present study addresses the effect of different concentrations of Na
2O on the structure of a composition of fresh C–S–H gels. The gels were synthesized from laboratory reagents, using calcium nitrate as the source of calcium and a sodium silicate solution for the silicon. A 10-M solution of NaOH was used to maintain a pH of over 13 throughout. The synthesized gels were exposed to different amounts of 8-M NaOH to determine their chemical stability and subsequently characterized with Fourier transform IR spectroscopy. The results showed that the addition of different concentrations of sodium leads to C–S–H gel modification even in the very short term.