Showing papers on "Calcium aluminates published in 1995"
TL;DR: In this paper, hydration reactions of MSW fly ash with an experimental C 12 A 7 / C 3 A -cement are investigated, and the same course of hydration is found for synthetic model mixtures of calcium aluminate + gypsum + alkali chlorides.
42 citations
TL;DR: In this paper, a kinetic study of delayed ettringite formation in hydrated Portland cement paste by XRD analysis over the temperature range 5 to 85 °C is reported.
33 citations
TL;DR: In this article, the effects of adjusting gypsum contents in blended, interground, fly ash cements were examined to examine the effects on sulfate resistance and compressive strength.
Abstract: Th objective of this study was to examine the effects of adjusting gypsum contents in blended, interground, fly ash cements. The adjustments in gypsum content were expected to affect sulfate resistance of the concrete by increasing the availability of sulfate ions during the hydration of calcium aluminates. In addition to studying the effects of gypsum content on sulfate resistance, its effects on mixing water requirements, compressive strength, and permeability were observed. The sulfate resistance of concrete containing Type II cement and high-calcium fly ash was improved by increasing the total gypsum content of the blended cements. The increases also caused increased mixing water requirements and decreased compressive strengths. The permeability of concrete was not affected significantly. The blended cement containing one of the two high-calcium fly ashes was particularly effective in improving the sulfate resistance with the increased gypsum contents.
9 citations
TL;DR: The interaction evidence of phenol moiety-calcium aluminate is proposed, based on the experimental data of differential scanning calorimetry and conduction calorIMetry, which suggested specific interactions between the phenol resin and calcium aluminate.
Abstract: Here we investigated the interactions of phenol resin precursor and calcium aluminates, in relation to a recently innovated cement based material having a high flexural strength of more than 120MPa. An anhydrous phenol resin precursor was used as the binder and water was not contained in the initial composition. The method of processing consists of mixing of the cement, the phenol resin precursor, and small amounts of N-methoxymethyl 6-nylon and glycerol under high shear. Addition of the 6-nylon and glycerol was necessary to produce viscoelastic cement paste through a twin roll mill. Setting of calendered sheets takes place during the heat curing at 200° C. The best combination for high flexural strength among all the cements tested is the mixture of calcium aluminate cement and the resole type of phenol resin. Resulting outstanding affinity suggested specific interactions between the phenol resin and calcium aluminate. We here propose the interaction evidence of phenol moiety-calcium aluminate, based on the experimental data of differential scanning calorimetry and conduction calorimetry.