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Strengthening of historic lime plaster by dispersion of nanoparticles of calcium hydroxide in alcohol
Slížková, Zuzana ; Frankeová, Dita
Preservation procedure suggests the technology of strengthening of the historic lime plasters, which is based on a liquid lime reinforcing agent impregnation - dispersions of nanoparticles of calcium hydroxide. The principle is in the use of new lime consolidant which thanks to the optimal concentration of lime (10 to 25 g / l), the lime particle size from 50 to 250 nm and the absence of water allows effective, compatible and economical reinforcing treatment during a relatively short time (1-3 weeks) . Preservation procedure is suitable for strengthening of plasters that contain pores or cracks larger than 1 micron.
Plný tet:  PDF
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Strengtheninig of whitish degraded porous limestone by suspension of nanoparticles of calcium hydroxide in alcohol
Slížková, Zuzana ; Frankeová, Dita
Limestone, which is damaged (degraded) in its surface layer, and having a suitable pore size, ie. that contain cracks or pores with a diameter greater than one micron, it is possible to consolidate by calcium hydroxide in the form of particles of a size of hundreds of nanometers. Suspension (also called dispersion, a colloidal sol) of nano-particles of calcium hydroxide in ethanol, may have different concentrations and can be applied to damaged limestone one or more times in various amounts, depending on its concentration and properties of the stone. The procedure specifies the limestone material tests carried out before the intervention and the possibility of minimizing whitish haze on the surface of the treated stone.
Fulltext: content.csg - PDF
Plný tet: 0448865_2015_Slizkova_Frankeova_Zpevneni_belaveho_degradovaneho_porezniho_vapence_suspenzi_nanocastic_hydroxidu_vapenateho_v_alkoholu_PP_4 - PDF
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Strengthening of weak historic renders with traditional and innovated consolidation treatment
Slížková, Zuzana ; Frankeová, Dita
The presented study was aimed to proof consolidation effects of different families of consolidants: inorganic agents (lime -based or silica-based solutions or sols), organic agents (silicic acid ester based consolidant) and their combination on the characteristics of weak mortars prepared in laboratory with different types of aggregates. Besides exploring consolidant-substrate interaction also the pozzolanic activity of the aggregate and the binder mortar component after reaction with lime (calcium hydroxide solution) was investigated in order to understand and describe the strengthening mechanism into consolidated mortars. As the study was based on experimental research, the production of mortar test specimens represented an important preliminary work. Different mortar components (various types of sand in terms of phase composition, clay, lime) and the same ratio of the aggregate and the binder were used in various mortar mixtures. Various mineralogical types of aggregate were used with the same grain size distribution (600 pieces of tubes of 40 mm in outer diameter, of the height of 40 mm and depth of 4 mm were prepared for testing the compressive strength, for the tension tests 550 thin plates of dimensions 40 mm x 100 mm x 4 mm were cast and 600 beams 20 x 20 x100mm were made for testing the flexural strength and other characteristics of reference and consolidated mortars). The sand used for mortar specimens was characterized by microscopic examination of thin section and also by X-ray diffraction, X-ray fluorescence spectroscopy and thermal analysis. The pozzolanic activity of the sands (reactivity with calcium hydroxide) was determined by means of the thermal analysis and supplemented by wet silicate analysis. The amount of the effective matter in the consolidant was the same for all agents per the square unit for all mortar types and specimen shape. One set of specimens was prepared as the reference set the second set was used for the evaluation.
Fulltext: content.csg - PDF
Plný tet: 0443951_2015_Slizkova_Frankeova_Strengthening_of_weak_historic_renders_with_traditional_and_innovated_consolidation_treatment - PDF
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The determination of material characteristics of natural and artificial stone samples from Marian Column at Hradčany Square in Prague
Slížková, Zuzana ; Zeman, Antonín ; Petráňová, Veronika ; Viani, Alberto ; Pérez-Estébanez, Marta ; Frankeová, Dita ; Ševčík, Radek ; Mácová, Petra ; Janotová, Dana ; Hasníková, Hana ; Niedoba, Krzysztof ; Hauková, Petra
Within the survey before restoration intervention material properties of natural and artificial stones that are part of the Marian Column at Hradcany Square in Prague were determined. 15 samples were subjected to extensive instrumental analysis, whose output is not only chemical and mineralogical composition of the samples, but also the degree of degradation including a description of the porous system and the level of salinity.
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