National Repository of Grey Literature 12 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
Preparation of concrete substrate for repair by continuous and pulsating oscillating water jets
Sitek, Libor ; Foldyna, Josef ; Wolf, I. ; Klich, Jiří ; Mazáčová, R.
The water jet ability to remove selectively degraded material can be further improved by introducing high-frequency pressure pulsation into the jet. A series of experiments was realized to compare the effects of both pulsating oscillating and continuous oscillating water jets on the concrete panel. Achieved results are presented in the paper.
Water Jet 2009. Proceedings
Sitek, Libor
Conference Water Jet 2009 - Research, Development, Application, which is organized by the Department of material disintegration of the Institute of Geonics of the ASCR, v. v. i., is the first meeting of producers, users, designers and other people interested in technology of high speed water jet in the Czech Republic. The main objective of the conference is to provide forum for exchange of knowledge, information and experiences in areas of research, development and application of water jet. Although the conference was originally intended as a more or less local meeting of experts from the Czech Republic, a number of foreign participants proves that this issue is very attractive far beyond the borders of the CR. Problems solved in contributions are very diverse: they range from basic research through traditional and less traditional application of technology in practice to reflection on the impact of the current economic crisis on job shops.
Adhesion between repair mortar and concrete surface processed using water jet
Mazáčová, R. ; Ščučka, Jiří ; Sitek, Libor ; Foldyna, Josef ; Hurta, J.
Results of an experiment focused on assessment of adhesion between a repair mortar and cement concrete surface processed using water jet are presented in the paper. The character of surfaces formed by both rotated continuous and rotated pulsating water jets is analysed. The adhesion between the repair mortar and processed surfaces is evaluated using adhesive strength tests.
Comparison of Continuous High-Pressure Generated and Pulsing Low-Pressure Generated Water Jets on Concrete
Mádr, V. ; Sitek, Libor ; Hela, R. ; Hlaváč, L. M. ; Bodnárová, L. ; Pustelník, J. ; Janurová, E.
The concrete samples with various erosion states were disintegrated by pure continuous water jets generated from pressure 380 MPa in the Liquid jet laboratory at the VŠB - Technical University of Ostrava. Simultaneously, the identical concrete samples were tested by pulsing water jets generated by low pressure 30 MPa in the Department of Material Disintegration at the Institute of Geonics of the AS CR. The erosion states of samples were prepared by application of several laboratory techniques simulating the concrete aging under the natural conditions due to the real applications in practice. They were prepared at the 127 Institute of Technology of Building Materials and Components of the Brno University of Technology. The influence of the erosion state on the disintegration rate was tested and the surface topography was studied. The comparison of both the depth of penetration and the volume disintegration ratio regarding the input power is performed.
Determination of the surface topography after the maintenance by the high-velocity water jet tool using the digital photography technique
Janurová, E. ; Pustelník, J. ; Sitek, Libor ; Mádr, V. ; Hela, R. ; Hlaváč, L. M. ; Bodnárová, L.
The topic of the contribution is to study surfaces of degraded materials after repair preparation performed by high-velocity water jet, especially the pulsing one. There were set up the optimal parameters for recording and evaluation of surfaces before the application of repair materials in civil engineering on model materials with artificially prepared corroded layers. Destructive action of high-velocity water jet on concretes of various qualities and corrosion damage degree were studied both experimentally and theoretically.
Advances in pulsating water jet technology
Foldyna, Josef
A research in the area of pulsating water jets is carried out systematically at the Institute of Geonics of the ASCR, v. v. i., in Ostrava since 2000. The research was oriented primarily at the study of processes of generating and forming of pulsating water jets and their effects on various materials. The paper presents results obtained in the area of numerical modelling of the process of generation of pulsating water jets and results of tests of pulsating water jets effects on materials.
Removal of surface layers of corroded concretes by high speed water jets
Sitek, Libor ; Bodnárová, L. ; Foldyna, Josef ; Nováková, Daria ; Ščučka, Jiří ; Martinec, Petr ; Hela, R. ; Mádr, V. ; Hlaváč, L.
Examples of removal of surface layers of concrete specimen (exposed to action of various aggressive medium) by high speed water fan jets are presented in this paper. Experimental laboratory research was focused on utilization of pulsating water jets and their comparison to commonly used continuous water jets.
Research in the area of pulsating water jets
Foldyna, Josef
A research in the area of pulsating water jets is carried out systematically in the Institute of Geonics AS CR, v. v. i., in Ostrava since 2000. The research was oriented primarily at the study of processes of generating and forming of pulsating water jets and their effects on various materials. The presented paper summarizes results obtained in the above mentioned areas during the period from 2000 to 2007.
Fan water jets in concrete disintegration
Sitek, Libor ; Martinec, Petr ; Foldyna, Josef ; Ščučka, Jiří ; Bodnárová, L. ; Hela, R. ; Mádr, V.
In this paper, possibilities of high speed water jet technology nowadays usually applied in repair of concrete structures are extended by application of so called fan (flat) jet. In concrete disintegration, one can achieve interesting results by relatively low energy intensity using such jet in co-operation with acoustic pulse generator.
Pulsating rotating waterjet during removing of surface layers
Sitek, Libor ; Bodnárová, L. ; Foldyna, Josef ; Hela, R. ; Ščučka, Jiří ; Jekl, Pavel ; Nováková, Daria
Paper deals with removing of concrete surface layers by high speed waterjet technology under laboratory conditions. Circumstances of removing of surface layers of various qualities by pulsating rotating jet were studied on concrete specimens. Results are compared to effect of continuous rotating jet on the identical concrete samples under the same operating conditions.

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