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Effect of ethylsilicate consolidating agents on behaviour and properties of glaukonitic sandstone used to building of St. Vitus´ Cathedral
Drdácký, Miloš ; Slížková, Zuzana ; Valach, Jaroslav
This report is focused on testing and evaluating of properties of chosen consolidating agends for concervation of relief bust in external triforium of St. Vitus´ Cathedral on Prague Castle (CZ). All tested agends contained ethyl ester of silicic acid (ethylsilicate) as active ingredient and were one-component. Penetration deepness of agends into sandstone and sandstone properties after application consolidating agends: bending strenght, modulus of elasticity, thermal expansion, vapour water permeability, hygric expansion were observed. The evaluated agends behaviour very similarly and there are no dramatically better or worse agends. All agends penetrate quite well into sandstone and relatively deep and increase strength of sandstone after impregnation.
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Experiment E3/2 - Vliv teploty na boční tlak sypkého tělesa
Valach, Jaroslav ; Koudelka, Petr
The first part of long-term experiment E3 with passive pressure has been started in the second half of 2001 and carried out during 2002. The partial experiment has been marked E3/2 according to the second type of the wall movement (rotation about the top). The paper presents the analysis of temperature changes of the stand structure at the results of the experiment E3/2.
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New Experimental Setup for Study of Physical Processes Preceding Specimen Failure
Vavřík, Daniel ; Bryscejn, Jan ; Holý, T. ; Jakůbek, J. ; Jakůbek, M. ; Valach, Jaroslav ; Vykydal, Z.
Failure of a high ductile specimen usually precedes a decrease of the loading force under the condition of displacement control in the monotonic loading. Unfortunately, the elastic energy stored in the standard loading equipment can result in sudden failure within very short time corresponding to the loading unstability. We can prolong this time interval by reducing the elastic energy in the loading equipment. The proposed new loading frame fulfils the indicated requirement and enables extraordinary precise displacement loading control even beyond the maximal loading force. Plastic deformation on a surface is investigated by the optical Method of Interpolated Ellipses and together with damage processes inside of the specimen are simultaneously observed by the X-ray Dynamic Defectoscopy method.
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