Browsing Ústav fyziky by Title
Now showing items 1-20 of 34
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The Acoustic Emission Parameters Obtained during Three-point Bending Test on Thermal-stressed Concrete Specimens
(Elsevier, 2017-06-02)Fire response of concrete structural members depends on thermal, mechanical, and deformation properties of concrete. These properties vary significantly with temperature and also depend on the composition and characteristics ... -
The Assessment of Cement Mortars after Thermal Degradation by Acoustic Non-destructive Methods
(IOP Publishing, 2017-10-25)Thanks, the terrorist attacks on the worldwide interest in the design of structures for fire greatly increased. One of the advantages of concrete over other building materials is its inherent fire-resistive properties. The ... -
The assessment of mechanical properties of thermally stressed composite materials using radio frequency electrical field
(IOP Publishing, 2018-07-01)The main topic of this paper is the testing of cement-based composite materials that were stressed by high temperature. Impedance spectroscopy has been used as a non-destructive measurement method. The specimens were made ... -
Carbon admixtures influence on the electrical properties of slag mortars focusing on alternating conductivity and permittivity
(Elsevier, 2016-08-01)New materials based on alkali-activated slag mortars may be an important contribution of applied research, which strives to offer the use of waste materials as a full replacement for the currently used binders and explores ... -
Comparison of results of impedance spectroscopy methods with results of impact-echo method in investigation of high-temperaturedegraded concrete
(Elsevier, 2016-08-01)The growth in the transport industry results in more accidents, which often include fire in locations with the concrete structures, which also effects its lifetime and its functionality. After any case of fire loading it ... -
Comprehensive Testing Techniques for the Measurement of Shrinkage and Structural Changes of Fine-Grained Cement-Based Composites during Ageing
(Hindawi Publishing Corporation, 2017-01-15)The paper deals with an experimental analysis focusing on the utilization of a specific measurement technique for determining the development of shrinkage and for monitoring structural changes in fine-grained cement-based ... -
Effect of steel fibres dosage in alkali-activated slag mortars on acoustic emission obtained during three-point bending tests
(EDP Sciences – Web of Conferences, 2017-05-24)The acoustic emission phenomenon is directly associated with nucleation of cracks in structural materials during loading. This paper analyses acoustic emission signals captured during three-point bending fracture tests of ... -
Electric conductivity changes in geopolymer samples with added carbon nanotubes
(Elsevier, 2016-08-01)By incorporation of nanotubes to the current composite materials, their properties can be significantly improved. Carbon nanotubes can act as filler, which minimizes the air gaps content in the matrix. The denser structure ... -
Electrical properties of alkali-activated slag composite with combined graphite/CNT filler
(IOP Publishing Ltd., 2017-10-25)Alkali-activated industrial by-products such as blast furnace slag are known to possess properties which are comparable to or even better than those observed for ordinary Portland cement. The combination of alkali-activated ... -
Evaluation of Rock Joint Coefficients
(IOP Science, UK, 2017-11-28)A computer method for evaluation of rock joint coefficients is described and several applications are presented. The method is based on two absolute numerical indicators that are formed by means of the Fourier replicas of ... -
Experimental Analysis of the Development of Elastic Properties and Strength under Different Ambient Temperature During the Hardening of Concrete
(Elsevier, 2017-07-20)This paper focuses on the experimental assessment of the degree to which continued exposure to low ambient temperatures influences the concrete modulus of elasticity and compressive strength. The elastic modulus is not a ... -
Experimental assessment of steel fibre reinforced concretes with different concentrations of fibres
(IOP Publishing, 2018-07-16)At present, steel fiber reinforced concrete can be classified as a composite material commonly used for load-bearing building structures. Adding steel fibers to fresh mixture improves its mechanical properties in comparison ... -
Experimental assessment of the influence of multiple cyclic loading on the dynamic modulus of elasticity of concrete
(EDP Sciences – Web of Conferences, 2017-05-24)The goal of the experiment was to determine the influence that cyclic loading has on concrete dynamic modulus of elasticity and compressive strength. Each test specimen was subjected to cyclic loading with the loading force ... -
Experimental evaluation of the effect of carbon fibres on acoustic emission parameters obtained during compressive strength tests of alkaliactivated slag composites
(IOP Publishing, 2018-07-12)The generation of acoustic emission signals is directly associated with formation of cracks in materials during loading. This paper deals with possibilities of acoustic emission method application as the tool for the ... -
Fitting Function for Flexural Strength of Cement Paste
(IOPPublishing, 2017-11-28)There are many analytical expressions for compressive strength as functions of porosity of cement-based materials but only a few such expressions exist for flexural strength of these materials. In the present paper a new ... -
Flexure response of thermal loaded concrete specimens by acoustic emission method
(EDP Sciences – Web of Conferences, 2017-05-24)The response to fire of concrete structural members depends on the thermal, mechanical, and deformation properties of concrete. These properties vary significantly with temperature depending on the composition and ... -
Fractal Analysis of Rock Joint Profiles
(IOP Publishing, 2017-11-28)Surface reliefs of rock joints are analyzed in geotechnics when shear strength of rocky slopes is estimated. The rock joint profiles actually are self-affine fractal curves and computations of their fractal dimensions ... -
Fracture properties of concrete specimens made from alkali activated binders.
(IOP Publishing, 2017-09-15)The aim of this paper is to quantify crack initiation and other fracture properties – effective fracture toughness and specific fracture energy – of two types of concrete with an alkali activated binder. The beam specimens ... -
Fracture response of alkali-activated slag mortars reinforced by carbon fibres
(IOP Publishing, 2018-07-12)The paper reports a study of the effect of carbon fibres on the mechanical fracture parameters of alkali-activated slag mortars. The carbon fibres were added in the amount of 1, 2 and 3%, respectively with respect to the ... -
Impact of graphite admixture on electrical properties of alkali-activated slag mortars
(EDP Sciences, 2017-05-24)One of the objectives of the applied research's striving consists in providing the users with new slag-mortar-based materials. Basic research, in its turn, aims at examining the newly created materials from the viewpoint ...