Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Inelastic neutron scattering investigation of hydrating tricalcium and dicalcium silicate mixture pastes: Ca(OH)2 formation and evolution of strength
INS (inelastic neutron scattering) results demonstrate an absolute maximum in the amount of Ca(OH)2 produced after 22 h by hydrating dicalcium and tricalcium silicate mixtures containing 90 % tricalcium silicate. These results correlate with compressive strength tests that also show an absolute maximum. These results are consistent with previous QENS (Quasielastic neutron scattering) results where a maximum in the rate and the predicted amount of hydration was observed for mixtures containing 80 % to 90 % tricalcium silicate. Hence, a small amount of dicalcium silicate accelerates the hydration, even though dicalcium silicate is less reactive than tricalcium silicate. This effect is attributed to the presence of additional sites for hydration products that are provided by the less reactive dicalcium silicate. This allows nucleation of C-S-H at sites remote from the tricalcium silicate, which is then free to hydrate further. It was also postulated that the similar atomic composition and hydration products of the two phases makes the dicalcium silicate surface favorable as a site for the nucleation and growth of products for the hydrating tricalcium silicate. It is advantageous to provide these nucleation sites using dicalcium silicate rather than inert particles because dicalcium silicate hydrates at a later time and becomes a significant contributor to the later strength of the paste. A local minimum in the compressive strength was also identified at mixture compositions containing 70 % to 75 % tricalcium silicate, which correlates with a previously observed minimum in the rate and predicted amount of hydration for mixtures containing 75.0 % to 77.5 % tricalcium silicate. Industrial cement clinker contains an approximate ratio of tricalcium silicate to total calcium silicate of 0.70 to 0.77, significantly below the ratio determined from this work of 0.85 to 0.9, for optimal hydration mechanics and strength properties, and within the composition range for the local minimum. There are other interactions between the remaining components in cement clinker left to explore, and it is intended that these will be the subject of future investigations.
Inelastic neutron scattering investigation of hydrating tricalcium and dicalcium silicate mixture pastes: Ca(OH)2 formation and evolution of strength
INS (inelastic neutron scattering) results demonstrate an absolute maximum in the amount of Ca(OH)2 produced after 22 h by hydrating dicalcium and tricalcium silicate mixtures containing 90 % tricalcium silicate. These results correlate with compressive strength tests that also show an absolute maximum. These results are consistent with previous QENS (Quasielastic neutron scattering) results where a maximum in the rate and the predicted amount of hydration was observed for mixtures containing 80 % to 90 % tricalcium silicate. Hence, a small amount of dicalcium silicate accelerates the hydration, even though dicalcium silicate is less reactive than tricalcium silicate. This effect is attributed to the presence of additional sites for hydration products that are provided by the less reactive dicalcium silicate. This allows nucleation of C-S-H at sites remote from the tricalcium silicate, which is then free to hydrate further. It was also postulated that the similar atomic composition and hydration products of the two phases makes the dicalcium silicate surface favorable as a site for the nucleation and growth of products for the hydrating tricalcium silicate. It is advantageous to provide these nucleation sites using dicalcium silicate rather than inert particles because dicalcium silicate hydrates at a later time and becomes a significant contributor to the later strength of the paste. A local minimum in the compressive strength was also identified at mixture compositions containing 70 % to 75 % tricalcium silicate, which correlates with a previously observed minimum in the rate and predicted amount of hydration for mixtures containing 75.0 % to 77.5 % tricalcium silicate. Industrial cement clinker contains an approximate ratio of tricalcium silicate to total calcium silicate of 0.70 to 0.77, significantly below the ratio determined from this work of 0.85 to 0.9, for optimal hydration mechanics and strength properties, and within the composition range for the local minimum. There are other interactions between the remaining components in cement clinker left to explore, and it is intended that these will be the subject of future investigations.
Inelastic neutron scattering investigation of hydrating tricalcium and dicalcium silicate mixture pastes: Ca(OH)2 formation and evolution of strength
Untersuchung der inelastischen Neutronenstreuung von hydratisierten Tricalciumsilicat- und Dicalciumsilicatpasten: Bildung von Ca(OH)2 und Festigkeitsentwicklung
Peterson, Vanessa K. (Autor:in) / Neumann, Dan A. (Autor:in) / Livingston, Richard A. (Autor:in)
Journal of Materials Research ; 21 ; 1836-1842
2006
7 Seiten, 4 Bilder, 22 Quellen
Aufsatz (Zeitschrift)
Englisch
| British Library Online Contents | 2006
Inelastic neutron scattering study of the hydration of tricalcium silicate
| British Library Online Contents | 1999
Inelastic neutron scattering study of the hydration of tricalcium silicate
| Tema Archiv | 1999
| British Library Online Contents | 2008