| Autor: |
M. Yousuf, Padmavathy Palta, David L. Cocke, Thomas R. Hess, R. K. Vempati, A. Mollah |
| Rok vydání: |
1995 |
| Předmět: |
|
| Zdroj: |
Cement and Concrete Research. 25:671-682 |
| ISSN: |
0008-8846 |
| DOI: |
10.1016/0008-8846(95)00055-h |
| Popis: |
The effects of sodium lignosulfonate superplasticizer on the hydration of Portland cement Type V have been investigated by XRD and FTIR techniques. The results of these studies indicate that the superplasticizer inhibits the hydration reaction as demonstrated by the reduced formation of Ca(OH) 2 as well as a lower degree of polymerization of the silicate anions. The hydration reaction seems to be controlled by dispersions of various charges present in hyperalkaline | solution in cement paste. The mechanism of inhibition is discussed and a ‘Charge Dispersed Tri-layer Model’ is proposed to explain the observed effects on the hydration reactions. According to this charge dispersal model, the Ca 2+ ions from initial hydration reactions go into the solution to form a tightly-bound bi-layer of counterions with the negatively charged calcium-silica-hydrate surface. Consequent to this intrinsic process, a tri-layer consisting of superplasticizer anions is immediately formed which inhibits further reactions. Possible consequences of the presence of superplasticizer on the solidification/stabilization of inorganic and organic pollutants by cementitious materials have also been discussed. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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