Acta Polytechnica CTU Proceedings. 2019 ( vol. 21-25): Poslední příspěvky
Zobrazují se záznamy 41-60 z 72
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EVALUATION OF UNDERGROUND STRUCTURES SUBJECTED TO SEISMIC LOADS
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2019)The paper is focused on the evaluation of the effect of earthquakes on underground structures. Free-field analysis is one solution of this task common mainly in engineering tunnelling practice, but it has some rather ... -
DEBRIS-FRETTING TEST OF COATED AND UNCOATED ZR-1%NB CLADDING
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2019)Debris fretting is one of the most significant fuel rod failure causes. An approach to mitigate this is to apply special coatings on the surface of the cladding that are supposed to increase the wear resistance. This paper ... -
RESIDUAL HEAT ESTIMATION OF NUCLEAR FUEL IN ENERGY WELL REACTOR
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2019)Energy Well (EW) is a concept of a small modular reactor, designed as a source of energy for places with low infrastructure. Its design combines TRISO fuel particles, graphite moderator and molten salt coolant. One of key ... -
A RETAINING WALL RECONSTRUCTION IN KUTNÁ HORA
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2019)This paper addresses the reconstruction of a historical stone retaining wall at the busy Kremnická – Táborská road in the town of Kutná Hora. The structure was in very poor condition. There was the danger of an accident ... -
RECONSTUCTION OF THE HISTORICAL BUILDING FOKSAL 13 AND 15 IN WARSAW
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2019)We were asked to design geotechnical structures to enable reconstruction of historical buildings. Buildings have to meet current standards so load bearing capacity had to be increased and underground garages can be built. ... -
A COMPARISON OF TESTING METHODS FOR DETERMINATION OF SPRAYED CONCRETE TENSILE STRENGTH
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2019)Sprayed concrete is important construction material in tunnelling. Primary lining is essential in NATM where the sprayed concrete can be loaded by tension due to bending moments. The tension is common reason of failure ... -
EFFECT OF NACL ON NEUTRON FLUX DENSITY IN GRAPHITE BLOCK
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2019)Aim of this work is to study the effect of NaCl on neutron flux through graphite block. Graphite block had 39 channels drilled through it and filled with NaCl. Au and In foils and In wire was used for neutron activation ... -
ASSESSMENT OF ADHESION BETWEEN BITUMINOUS BINDER AND MINERAL AGGREGATE USING DIGITAL IMAGE ANALYSIS
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2019)Asphalt mixtures often fail due to a low adhesion of bituminous binder to mineral aggregate, which leads to surface coarse damages like potholes and fatigue cracking. To avoid this phenomenon, different types of adhesion ... -
EFFECT OF BACTERIA BACILLUS PSEUDOFIRMUS AND FUNGUS TRICHODERMA REESEI ON SELF-HEALING ABILITY OF CONCRETE
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2019)There are usually used inorganic substances for the strengthening of self-healing ability of concrete but some specific types of bacteria or fungi may also be considered for use. The bacteria’s ability to fill pores and ... -
FRESH STATE PROPERTIES OF LIME MORTARS WITH FLAX OIL ADMIXTURE
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2019)Flax oil has been used as mortar improving, hydrophobic, admixture already in ancient times. The paper describes the identification of flax oil in mosaic mortar from ca. 1900 by help of FTIR spectroscopy. This historic ... -
OPTIMIZATION OF MIX-DESIGN OF CHEMICALLY RESISTANT SPRAYED CONCRETE
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2019)This paper addresses optimization of mix-design and granulometric curves of aggregate of chemically resistant cementitious sprayed mix. The target of the paper is to improve properties of currently developed mix-design, ... -
THE INFLUENCE OF A SHRINKAGE REDUCING ADMIXTURE ON THE LONG-TERM DEVELOPMENT OF DYNAMIC PROPERTIES IN ALKALI-ACTIVATED SLAG
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2019)The paper investigates the way a shrinkage-reducing admixture affects the long-term development of dynamic properties in mortars made with alkali-activated slag (AAS). Two AAS mortars were tested - one contained a ... -
THE LIGHTWEIGHT TEXTILE REINFORCED CONCRETE FOR THIN-WALLED STRUCTURES
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2019)The article deals with lightweight concrete with non-conventional reinforcement and its application in thin-walled structures. As part of experimental research, several sets of thin-walled slab and complementary specimen ... -
AUTOGENOUS SHRINKAGE OF COMPOSITES BASED ON PORTLAND CEMENT
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2019)Autogenous shrinkage of cement based composites is important property influencing number of their engineering application. Its ultimate value is predominantly determined by mineralogical composition of cement and its ... -
SHORT-TERM CORROSION RESPONSE OF METALS IN LIME MORTAR
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2019)Even though the corrosion of steel in concrete is very well described, the corrosion processes in lime environment studied very rarely. This environment is obviously also basic and its pH decreases in time, but the obtained ... -
RECONSTRUCTION OF THE MONASTERY NEXT TO THE PRAGUE CASTLE
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2019)The paper deals with a rehabilitation of the historic building of Carmel Monastery next to the Prague Castle. A structural survey of building was carried out and the historical drainage and ventilation system was identified. ... -
PLASMA MODIFICATION OF POLYVINYL ALCOHOL MICROFIBERS TO IMPROVE COHESION WITH CEMENT MATRIX
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2019)The article describes plasma modifications of the surface of polyvinyl alcohol (PVA) microfibers using oxygen and hydrogen plasma in order to improve the properties of the composite material containing modified microfibers, ... -
USE OF FINELY GROUND RECYCLED CONCRETE FOR IMPROVEMENT OF INTERFACIAL ADHESION IN FIBER-REINFORCED CEMENTITIOUS COMPOSITES
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2019)This paper deals with an improvement and an assessment of a polymeric macro-fibers adhesion to the cement matrix. For this purpose, two approaches were employed – (i) roughening of fibers using a plasma treatment and (ii) ... -
MICROSCOPICAL AND MICROMECHANICAL FEATURES OF HIGH PERFORMANCE CONCRETE CONTAINING LOW LEVELS OF FLY ASH
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2019)Alkali activated fly ash is a widely used admixture to the concrete. Due to the pozzolanic activity, the fly ash can replace up to 60 mass percentage. The impact of fly ash on the concrete depend on the level of it content, ... -
TECHNOLOGY OF PREPARATION OF BARIUM AND MAGNESIUM HYDROXIDE NANODISPERSION AND POSSIBILITIES OF THEIR USE IN MONUMENT CARE
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2019)An application of hydroxide nanoparticles in preservation of cultural heritage attracted great interest. The nanodispersions of calcium, magnesium or barium hydroxides exhibit high performance in consolidation abilities. ...