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Pozzolanic reaction in the presence of chemical activators: Part II. Reaction products and mechanism
This paper has dealt with the pozzolanic reaction products and mechanism in lime-pozzolan cement pastes in the presence of Na2SO4 and CaCl2. X-ray diffraction (XRD) analysis indicated that the hydration products in control lime-natural pozzolan pastes were calcium silicate hydrate (C-S-H) and C4AH13. The addition of Na2SO4 to lime-natural pozzolan paste accelerated the pozzolanic reaction and resulted in the formation of AFt, instead of C4AH13, which endorsed the paste a higher strength compared with the control pastes. The introduction of 4% CaCl2 dot 2H2O decreased the pH of lime-pozzolan pastes, but favoured the formation of the solid solution of C3A dot Ca(OH)2 dot 12H2O-C3A dot CaCl2 dot 10H2O. As the curing temperature was raised from 23 degree C to 65 degree C, it accelerated the reaction rates in all these pastes. The hydration products in the control and the CaCl2 activated pastes did not change with temperature, but AFm appeared in the Na2SO4 activated pastes when temperature was above 50 degree C.
Pozzolanic reaction in the presence of chemical activators: Part II. Reaction products and mechanism
This paper has dealt with the pozzolanic reaction products and mechanism in lime-pozzolan cement pastes in the presence of Na2SO4 and CaCl2. X-ray diffraction (XRD) analysis indicated that the hydration products in control lime-natural pozzolan pastes were calcium silicate hydrate (C-S-H) and C4AH13. The addition of Na2SO4 to lime-natural pozzolan paste accelerated the pozzolanic reaction and resulted in the formation of AFt, instead of C4AH13, which endorsed the paste a higher strength compared with the control pastes. The introduction of 4% CaCl2 dot 2H2O decreased the pH of lime-pozzolan pastes, but favoured the formation of the solid solution of C3A dot Ca(OH)2 dot 12H2O-C3A dot CaCl2 dot 10H2O. As the curing temperature was raised from 23 degree C to 65 degree C, it accelerated the reaction rates in all these pastes. The hydration products in the control and the CaCl2 activated pastes did not change with temperature, but AFm appeared in the Na2SO4 activated pastes when temperature was above 50 degree C.
Pozzolanic reaction in the presence of chemical activators: Part II. Reaction products and mechanism
Shi, Caijun (Autor:in) / Day, R.L. (Autor:in)
Cement and Concrete Research ; 30 ; 607-613
2000
7 Seiten, 15 Quellen
Aufsatz (Zeitschrift)
Englisch
Natriumsulfat , Calciumchlorid , Röntgenbeugung , Röntgenanalyse , Hydratisieren , Reaktionskinetik , Konzentrationseinfluss , feste Lösung , Temperatureinfluss , Mikrostruktur , Aktivierungsanalyse , Puzzolanzement , chemische Aktivierung , Calciumsilicathydrat , Calciumaluminathydrat , Zementpaste , Puzzolanreaktion
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