Frank Bellmann

TL;DR: In this paper, it is shown that activation is also possible by lowering the pH to a range between 11.8 and 12.2 by the addition of calcium hydroxide and soluble calcium salts.

TL;DR: In this paper, the sulfate concentration required to form gypsum from portlandite was derived from thermodynamic calculations and experimental measurements, and the obtained results were compared to the sulfates concentrations in laboratory solutions that are commonly used to test the performance of concrete exposed to sulfate attack and also to sulfates that can be expected under field conditions.

TL;DR: In this article, a phase containing uncondensed silicate monomers close to hydrogen atoms (either hydroxyl groups or water molecules) was formed in both experiments, and it was used to emphasize that the hydration of tricalcium silicate proceeds in two consecutive steps, in the first reaction, an intermediate phase containing hydrated silicates monomers is formed which is subsequently transformed into C-S-H as the final hydration product in the second step.

TL;DR: In this paper, the presence or absence of calcium hydroxide plays a vital role in the resistance of cement paste or concrete against the formation of thaumasite, and the results confirm the conclusions of earlier thermodynamic calculations that the presence of calcium hyroxide has an important impact on the formation.

TL;DR: In this paper, it is suggested that the formation of thaumasite at low and moderate sulphate concentrations in the attacking solution can be avoided by lowering the calcium/silicon ratio in the C-S-H phases.