Now showing items 21-34 of 34

  • Electrical properties of alkali-activated slag composite with combined graphite/CNT filler 

    Rovnaník, Pavel; Míková, Maria; Kusák, Ivo (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 ...
  • Large Rock Reliefs and Their 3D Reconstructions 

    Audy, Ondřej; Ficker, Tomáš (IOP Publishing, 2017-11-28)
    Rock reliefs are used for assessing joint rock coefficients that serve in geotechnical engineering for computing shear strength of rock joints. The three-dimensional reliefs of small rock joints amounting to several ...
  • Rupture Strength and Irregularity of Fracture Surfaces 

    Ficker, Tomáš (IOP Publishing, 2017-11-28)
    Textural irregularities of fracture surfaces of cement-based materials seem to be an interesting source of information on some mechanical properties. Besides compressive strength, the flexural strength is strongly correlated ...
  • Macrodefects and Microdefects within Porous Cement Pastes 

    Ficker, Tomáš (IOP Publishing, 2017-11-28)
    It is shown that the mechanical strength of cement matrix (hydrated cement paste) is a result of competitive interplay between macrodefects and microdefects. The dominance of one of these two kinds of defects depends not ...
  • Rock Joint Coefficients Derived from the Three-Dimensional Fourier Reliefs 

    Audy, Ondřej; Ficker, Tomáš (IOP Publishing, 2017-11-28)
    Coefficients of rock joints serve in geotechnical practice for determining shear strength of rock masses. Evaluation of the stability of rocky terrains containing joints is important from the viewpoint of safety. Larger ...
  • Evaluation of Rock Joint Coefficients 

    Audy, Ondřej; Ficker, Tomáš (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 ...
  • Fitting Function for Flexural Strength of Cement Paste 

    Ficker, Tomáš (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 ...
  • Fractal Analysis of Rock Joint Profiles 

    Audy, Ondřej; Ficker, Tomáš (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 ...
  • Rock Joint Asperities and Mechanical Strength of Concrete 

    Ficker, Tomáš; Komárková, Tereza (IOP Publishing, 2017-11-28)
    Mechanical interactions between concrete foundations of large civil engineering structures (tunnels, bridges or dams) and the asperity surfaces of rock masses represent a useful topic for investigation. It is obvious that ...
  • Experimental evaluation of the effect of carbon fibres on acoustic emission parameters obtained during compressive strength tests of alkaliactivated slag composites 

    Topolář, Libor; Rovnaník, Pavel; Schmid, Pavel (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 ...
  • Fracture response of alkali-activated slag mortars reinforced by carbon fibres 

    Šimonová, Hana; Topolář, Libor; Schmid, Pavel; Keršner, Zbyněk; Rovnaník, Pavel (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 ...
  • Experimental assessment of steel fibre reinforced concretes with different concentrations of fibres 

    Komárková, Tereza; Láník, Jaromír; Topolář, Libor; Štoller, Jiří; Stoniš, Patrik (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 ...
  • Properties of concrete intended for further testing measured by the Impact-Echo and the ultrasonic pulse method 

    Karel, Ondřej; Dvořák, Richard; Rozsypalová, Iva; Schmid, Pavel (IOP Publishing, 2018-07-16)
    The aim of the paper is non-destructive measurement of differently degraded specimens by high temperature intended for further testing of joints of stainless steel helical reinforcement glued into the groove and differently ...
  • Electrical and Self-Sensing Properties of Alkali-Activated Slag Composite with Graphite Filler 

    Rovnaník, Pavel; Kusák, Ivo; Bayer, Patrik; Schmid, Pavel; Fiala, Lukáš (MDPI, 2019-05-16)
    The electrical properties of concrete are gaining their importance for the application in building construction. In this study, graphite powder was added to alkali-activated slag mortar as an electrically conductive filler ...