Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Resistance of sodium polyphosphate-modified fly ash/calcium aluminate blend cements to hot H2SO4 solution
Sodium polyphosphate-modified Class F fly ash/calcium aluminate blend (SFCB) cements were prepared at room temperature and their resistance to hot acid erosion was evaluated by submerging them in H2SO4 solution (pH 1.6) at 90 degree C. Sodium polyphosphate preferentially reacted with calcium aluminate cement (CAC) to form amorphous Ca(HPO4).xH2O and Al2O3.xH2O gel, rather than fly ash. These amorphous reaction products, which bound the partially reacted and unreacted CAC and fly ash particles into a coherent mass, were responsible for strengthening and densifying the SFCB specimens at room temperature, playing an essential role in mitigating their acid erosion. In these cements, the extent of acid erosion depended primarily on the ratio of fly ash/CAC; namely, those with a higher ratio underwent a severe erosion. This effect was due to the formation of a porous structure, which allowed acid to permeate the cement easily, diminishing the protective activity of Ca(HPO4).xH2O and Al2O3.xH2O gel against H2SO4.
Resistance of sodium polyphosphate-modified fly ash/calcium aluminate blend cements to hot H2SO4 solution
Sodium polyphosphate-modified Class F fly ash/calcium aluminate blend (SFCB) cements were prepared at room temperature and their resistance to hot acid erosion was evaluated by submerging them in H2SO4 solution (pH 1.6) at 90 degree C. Sodium polyphosphate preferentially reacted with calcium aluminate cement (CAC) to form amorphous Ca(HPO4).xH2O and Al2O3.xH2O gel, rather than fly ash. These amorphous reaction products, which bound the partially reacted and unreacted CAC and fly ash particles into a coherent mass, were responsible for strengthening and densifying the SFCB specimens at room temperature, playing an essential role in mitigating their acid erosion. In these cements, the extent of acid erosion depended primarily on the ratio of fly ash/CAC; namely, those with a higher ratio underwent a severe erosion. This effect was due to the formation of a porous structure, which allowed acid to permeate the cement easily, diminishing the protective activity of Ca(HPO4).xH2O and Al2O3.xH2O gel against H2SO4.
Resistance of sodium polyphosphate-modified fly ash/calcium aluminate blend cements to hot H2SO4 solution
Sugama, T. (Autor:in) / Weber, L. (Autor:in) / Brothers, L.E. (Autor:in)
Cement and Concrete Research ; 29 ; 1969-1976
1999
8 Seiten, 11 Quellen
Aufsatz (Zeitschrift)
Englisch
ARTICLES - Hot acid resistance of polymer-modified calcium aluminate-fly ash-polyphosphate cements
| Online Contents | 2000
| British Library Online Contents | 2000