Papers by Keyword: Aluminate Cement

Abstract: Stucco products due to the specific nature should be characterized by a short time of the beginning and end of setting, low shrinkage, good adhesion to the substrates and workability at running. The type of cement used has a significant influence on this parameter. The change in the physical properties of stucco mortars in which Portland cement was gradually replaced with AliCem sulphoaluminate cement and Górkal 70 aluminate cement. For this purpose, two sets of samples were prepared, in the first set the percentage of Górkal 70 cement in relation to the entire cement was 15, 20, 25, 30 and 33%, in the second set the percentage of Alicem cement was 25, 50, 75 and 100%. The research results indicate that both cements significantly shortened the setting time of the mortars, reduced the shrinkage and improved adhesion to the substrates.

Abstract: This article is focused on thermal expansion of cement-based composite. Studied materials are concrete containing alumina cement, silica aggregates and they are reinforced by basalt fibres. Three different concrete varying in fibres length were prepared and its basic physical properties and thermal expansion were measured. Fibres lengths were 6mm and 12mm. Total amount of fibres in mixtures were constant, whereas the ratio of the fibers were changed. Results were compared with reference concrete with no fibres. It was proved positive effect of fibres on thermal expansion, when the lowest values of thermal strain were shown by material with just longer fibres.

Abstract: Macro-defect-free (MDF) cements are cement-polymer composites and were developed by Birchall et al. three decades ago. The composites are produced by mixing small amounts of polymer and water with cement. However, they have a different production method than that of cement pastes, which was inspired by rubber production. Mixtures of cement, polymer and water are processed by using a two-roll mill. The composites are known with their high flexural strengths. Unfortunately, there are not any known commercial products using MDF cements because of their poor durability under moisture. In this study, MDF cements were prepared by using poly(vinyl alcohol--vinyl acetate) PVA, calcium aluminate cements and two different types of epoxy resins. Epoxy resins were a diglycidyl ether of bisphenol A and a mixture of a diglycidyl ethers of bisphenol A and F. Durability performance was compared with respect to biaxial flexural strengths, contact angle and atomic force microscopy (AFM) for the specimens stored in water.