English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We reconsider a number of measurements for the overall hydration kinetics oftricalcium silicate pastes having an initial water to cement weight ratio closeto 0.5. We find that the time dependent ratio of hydrated and unhydrated silicamole numbers can be well characterized by two power-laws in time, $x/(1-x)\sim(t/t_x)^\psi$. For early times $t < t_x$ we find an `accelerated' hydration($\psi = 5/2$) and for later times $t > t_x$ a `deaccelerated' behavior ($\psi= 1/2$). The crossover time is estimated as $t_x \approx 16 hours$. Weinterpret these results in terms of a global second order rate equationindicating that (a) hydrates catalyse the hydration process for $t<t_x$, (b)they inhibit further hydration for $t > t_x$ and (c) the value of theassociated second order rate constant is of magnitude 6x10^{-7} - 7x10^{-6}liter mol^{-1} s^{-1}. We argue, by considering the hydration process actuallybeing furnished as a diffusion limited precipitation that the exponents $\psi =5/2$ and $\psi = 1/2$ directly indicate a preferentially `plate' like hydratemicrostructure. This is essentially in agreement with experimental observationsof cellular hydrate microstructures for this class of materials.Comment: RevTeX macros, 6 pages, 4 postscript figure

Global hydration kinetics of tricalcium silicate cement