โ Scribed by A. Goldschmidt
No coin nor oath required. For personal study only.
In order to evaluate the hydration process assumed by the Le-Chatelier theory for portland cement, the morphology and chemical composition of the residue left after the evaporation of the liquid phase was studied by electron microprobe and electronmicroscopy. The association Ca-Si-AI and the isolated elements Ca, K and Na were identified in the residue. However, the association Ca-Si was not found, which agrees with the topochemical hydration theory. It is concluded that the liquid phase of commercial portland cement is basically an equilibrium solution of NH, KH and CH; other phases appearing only as traces.
Se estudi6 la morfolog{a y la composici6n quimica del residuo s61ido obtenido de la evaporaclon de la fase liquida de una pasta de cemento portland, con el objeto de reproducir el proceso que supone la teoria de la hydrataci6n del cemento portland de Le-Chatelier; esto se hizo con microscopla electr6nica de barrido y microan~lisis de rayos X. En este residuo de encontraron con microan~lisis la asociaci6n Ca-Si-AI y los elementos aislados Ca, K y Na. No se encontr6 la asociaci6n Ca-Si, Io que est~ de acuerdo con la teor{a topoqu{mica de la hidrataci6n. Se puede afirmar que basicamente, la fase liquida de un cemento portland comercial es una soluci6n en equilibrio de NH, KH y CH con otros vestigios de otras fases.
๐ SIMILAR VOLUMES
The composition of the calcium silicate hydrate (C-S-H) present in Portland cement pastes from eight days to five years old, and in concrete samples ten years old, has been determined by electron probe mlcro-analysis. The dependence of C-S-H composition on water/cement ratios has also been studied.
The hydration of portland cement in presence of citric acid has been investigated. The results indicate that O.l% citric acid accelerates whereas too high a dose (> 0.1%) of citric acid retards the hydration. Electrical conductivity measurements of the paste indicate that in the presence of citric a