Showing papers on "Ettringite published in 1981"
TL;DR: In this paper, the authors examined the mechanism of C 4 A 3 S expansion, ettringite formation and its thermal stability in a 3-part study, and determined phase equilibria describing ettric stability as a function of pressure.
95 citations
Patent•
03 Aug 1981
TL;DR: In this paper, it was shown that the only significant factor contributing to strength during the early stages of hydration is the formation of an amount of ettringite equal to from about 40% to about 60% of the weight the paste of water, the high alumina cement, the gypsum source, and the lime source.
Abstract: A rapid reaction of high alumina cement, gypsum, lime and water produces cementitious compositions in which the only significant factor contributing to strength during the very early stages of hydration (i.e., a few minutes to a few hours) is the formation of an amount of ettringite equal to from about 40% to about 60% of the weight the paste of water, the high alumina cement, the gypsum source, and the lime source. A substantially impermeable concrete having a 4-hour compressive strength of about 8000 p.s.i. may be produced from the cement powder of this invention.
65 citations
TL;DR: In this paper, the effect of free CaO content in portland cement clinker upon the expansion of specimens of expansive cements, prepared in semi-commercial scale by intergrinding of C4A3 S -phase containing special clinker and gypsum, by means of examination of liquid phase composition and porosity of mortars, have been presented.
23 citations
TL;DR: In this paper, the authors examined the hydration of Portland cements with tartaro-and titanogypsum and found that they produced much more ettringite than those with titan and natural gypsum.
16 citations
TL;DR: In this paper, the surface area changes are due to changes in the size and subsequent growth of the ettringite crystallites, which is affected by the available pore space, and the authors gave direct evidence in favour of a through-solution mechanism at least beyond one day of hydration.
9 citations
TL;DR: In this article, the formation of calcium trisulphoaluminate (ettringite) by action of the sulphate ion on granites in a calcium hydroxide-saturated medium was investigated.
8 citations
Patent•
10 Mar 1981
TL;DR: In this article, a mixture of lime and gypsum was used for the production of tobermorite, and the reaction mixture was filtered to separate the toberminerite therefrom.
Abstract: A lime material and a siliceous material containing 10 to 40% by weight of alumina are admixed with an alkali solution, and the mixture is subjected to hydrothermal reaction with saturated water vapor at 4 to 40 kg/cm 2 to form tobermorite. The reaction mixture is filtered to separate the tobermorite therefrom. A lime material and a gypsum material are added to the resulting filtrate, and the mixture is reacted at room temperature to a temperature of 90° C. to form ettringite. The alkali filtrate separated from the ettringite is reused for the production of tobermorite.
7 citations