Year: 1976
Type: article
Abstract: The results of this study on the effects of sodium on potential calcium silicate hydrate binders showed the fol lowing.Pectolite, N a 2 0 -4CaO•6Si0 2 -f^O, is a stable phase over a wide temperature range in the system.At higher N a 2 0 concentrations pectolite appears to co-exist with a sodium silicate gel.It may possibly contain lattice Na+ in excess of that in the formula.The phase N a 2 0 -2CaO• 2SiC>2 'I^O, re ported previously, was synthesized unreproducibly; it appears to be a metastable phase.Tobermorite may accommodate a small amount of Na+ in its lattice, but xonotlite and foshagite do not.Sodium sulfate and sodium carbonate reacted to various extents, ^depending on concentration and temperature and time of exposure, with a 7% A ^O ^ substituted tobermorite forming CaSO^ and CaCO^, respectively.The NaCl reaction with the to bermorite was minimal at 250°C; at 325°C the NaCI still ap peared in the product but the tobermorite transformed to xon otlite .
Author: Erik B. Nelson
Language: English
Subfield: Civil and Structural Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W3131933490