Effect of temperature on the microstructure of calcium silicate hydrate (C-S-H)
TL;DR: In this paper, the modifications to C-S-H induced by isothermal curing between 5 and 60 degrees C were studied and it was shown that the microstructure of the cement paste is much coarser and porous, which explains the lower final strength obtained by curing at elevated temperatures.
About: This article is published in Cement and Concrete Research.The article was published on 2013-11-01. It has received 334 citations till now. The article focuses on the topics: Calcium silicate hydrate & Silicate.
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TL;DR: In this paper, the growth of C-S-H is the principal factor controlling the main heat evolution peak and after several days space becomes the major factor controlling hydration, but deceleration cannot be attributed to diffusion control.
705 citations
TL;DR: In this paper, a review on the relationship between the composition, the structure and the solution in which calcium silicate hydrate (C-S-H) is equilibrated is presented.
312 citations
TL;DR: In this paper, the authors introduced a new rapid, relevant and reliable (R 3 ) test to predict the pozzolanic activity of calcined clays with kaolinite contents ranging from 0 to 95%.
296 citations
TL;DR: In this article, the degree of reaction of slag in blended pastes is measured using a combination of Selective dissolution and differential scanning calorimetry, but the absolute heat of hydration or contribution to chemical shrinkage of any particular slag is not known.
273 citations
TL;DR: In this article, the effect of temperature on the structure and solubility of calcium aluminosilicate hydrate (C-A-S-H) was investigated.
239 citations
Cites background from "Effect of temperature on the micros..."
...The relationship between temperature and bound water content in tobermorite [40] and hydrated PC pastes [2] is different; these materials dehydrate progressively with increasing temperature over this temperature range ....
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...procedure here than in a recent study of temperature effects on PC pastes [2] explains why...
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...microstructures [2], and decreasing compressive strength s [3] with increasing temperature ....
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References
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TL;DR: In this article, a new analysis tool was developed to quantify the experimentally observed changes in morphology of portlandite, allowing the calculation of the relative surface energies of the crystal facets.
2,498 citations
TL;DR: This study measures the composition and solid density of the principal binding reaction product of cement hydration, calcium-silicate-hydrate (C-S-H) gel, one of the most complex of all gels, and quantifies a nanoscale calcium hydroxide phase that coexists with C- S-H gel.
Abstract: Although Portland cement concrete is the world’s most widely used manufactured material, basic questions persist regarding its internal structure and water content, and their effect on concrete behaviour. Here, for the first time without recourse to drying methods, we measure the composition and solid density of the principal binding reaction product of cement hydration, calcium–silicate–hydrate (C–S–H) gel, one of the most complex of all gels. We also quantify a nanoscale calcium hydroxide phase that coexists with C–S–H gel. By combining small-angle neutron and X-ray scattering data, and by exploiting the hydrogen/deuterium neutron isotope effect both in water and methanol, we determine the mean formula and mass density of the nanoscale C–S–H gel particles in hydrating cement. We show that the formula, (CaO)1.7(SiO2)(H2O)1.80, and density, 2.604 Mg m−3, differ from previous values for C–S–H gel, associated with specific drying conditions. Whereas previous studies have classified water within C–S–H gel by how tightly it is bound, in this study we classify water by its location—with implications for defining the chemically active (C–S–H) surface area within cement, and for predicting concrete properties.
827 citations
TL;DR: In this article, the phase assemblage and pore solution of Portland cements hydrated between 0-60°C were modeled as a function of time and temperature, and a good correlation between calculated porosity and measured compressive strength was observed.
785 citations
TL;DR: In this article, a second generation model for the nanostructure of C-S-H based on the interpretation of water sorption isotherms is presented, which can help to establish quantitative relationships between the nano-structural and bulk properties.
767 citations
TL;DR: In this paper, the effect of temperature on the hydration products and the composition of the pore solution are investigated for two Portland cements from 5 to 50°C, and the results show that at 40 and 50 °C, the formation of denser C-S-H, a more heterogeneous distribution of the hyration products, a coarser porosity, a decrease of the amount of ettringite as well as the formation and formation of very short etteringite needles has been observed.
532 citations