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In all cases, the water contained in concrete does not get frozen. All the results are similar to result on Figure 5. 84 Temperature [K] 320 300 280 260 240 220 200 1275 1325 1375 1425 1475 1525 1575 1625 Time [days] Freezing point of water Temperature Hygroscopic moisture content Moisture content Figure 4: Hygrothermal properties of concrete, concrete wall (CM) provided by exterior plaster, 2 mm from material interface Concrete wall provided with thermal insulation system EPS as the insulation material provided with plaster reliably keeps the concrete wall from effects of freezing cycles no matter which type of concrete is under consideration. Temperature [K] 320 300 280 260 240 220 200 1275 1325 1375 1425 1475 1525 1575 1625 Time [days] Freezing point of water Temperature Hygroscopic moisture content Moisture content Figure 5: Hygrothermal performance in exterior plaster, concrete wall (CS) provided by EPS with exterior plaster, 2 mm under the surface Nevertheless, disadvantage of this material combination lies in abnormal strain of exterior plaster caused by weather conditions. In the simulation we counted more than 25 freezing cycles in every material combination in exterior plaster per reference year (Figure 6). Duration of freezing cycles is different. The longest one takes 36 hours, the shortest one only 1 hour. Single cycles are separated by tiny temperature or moisture fluctuations which raise their final number. 0.080000 0.070000 0.060000 0.050000 0.040000 0.030000 0.020000 0.010000 0.000000 Moisture content by volume [m3/m3] 0.180000 0.160000 0.140000 0.120000 0.100000 0.080000 0.060000 0.040000 0.020000 0.000000 Moisture content by volume [m3/m3]
Mineral wool has the same effect as EPS and protects the concrete wall from increase of moisture content and decrease of temperature at the same time. This prevents water in the wall getting overhygroscopic and getting frozen. Anyway, exterior plaster applied on mineral wool is abnormally exposed too. The number of freezing cycles during one reference year is little bit smaller then in plaster applied on EPS and counting about 25 cycles in every material combination (Figure 7). Temperature [K] 320 300 280 260 240 220 200 1275 1325 1375 1425 1475 1525 1575 1625 Time [days] Freezing point of water Temperature Hygroscopic moisture content Moisture content Figure 6: Hygrothermal performance in exterior plaster, concrete wall (CF) provided by mineral wool with exterior plaster, 2 mm under the surface As we can see, the cycles are separated by tiny moisture and temperature fluctuations, too. Discussion In an assessment of the impact of freezing cycles on service life of exterior renders, it is not enough to consider only the frost resistance determined in the laboratory. It is important to realize, that the number of freezing cycles depends on material combination, not only on material characteristics of used materials. As important as the freezing cycles’ time is the lag between two cycles. If the freezing cycles’ time is too short, water can not solidify into ice and can not disrupt the structure of plaster. By the same token, if the lag between two cycles is too short, ice can not melt back into water and then refreeze again, so its destruction effect can be neglected and we can consider both as one. When we evaluate the number of freezing cycles taking these considerations into account, we get new number of freezing cycles which is reduced (Table 5). Table 5: Number of freezing cycles after reduction LCP CF CM CS CR EPS MW LPMH - 0 - - - - - - Simple concrete wall - - - - 0 - - 0 - - - - - - - - - - - - 0 - - - Concrete wall provided with 0 0 - - - - - 0 exterior plaster 0 - 0 - - - - 0 0.080000 0.070000 0.060000 0.050000 0.040000 0.030000 0.020000 0.010000 0.000000 Moisture content by volume [m3/m3] 85
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Thermophysics 2009 29 th and 30 th
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Content Ivan Baník, Jozefa Lukovi
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Measurement of the thermo‐physica
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As the right side of the previous r
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The initial vector k r in the k1, k
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2.4 The computer programs testing T
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Investigation of moisture influence
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⎛ t t ⎞ −1 ⋅ ln⎜ ⎝ tm t
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Density [kg.m -3 ] 620 600 580 560
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for a new building have to be great
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Fig.1. Photo of the hot ball sensor
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Fig.6.Left: formation of blocks. Ri
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4. Conclusions With this experiment
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1a. Three‐dimensional temperature
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n+ ∞ ( ) 4 ( ) ∑ π n= 1 ( 2 1)
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a 2 2 ( Fo) ⎛ l ⎞ r = ⎜ ⎟
Page 33 and 34: Substitution of ordinates of the in
Page 35 and 36: Moisture transport through porous m
Page 37 and 38: Data acquired through the hot ball
Page 39 and 40: In this way, the water spreading wa
Page 41 and 42: Thermal conductivity [W m -1 K -1 ]
Page 43 and 44: Relationship between relative permi
Page 45 and 46: ( ) i n Φ − Φ K i = ki i i, cri
Page 47 and 48: Figure 4: Comparison of measured an
Page 49 and 50: Computational modelling of coupled
Page 51 and 52: a ξ = d 2 ( lnκ − lnκ ) lnξ +
Page 53 and 54: on the results of experiments and c
Page 55 and 56: Figures 8a, b: Moisture content (a)
Page 57 and 58: Conclusions The computer simulation
Page 59 and 60: properties as are the bulk density,
Page 61 and 62: elation determined from the measure
Page 63 and 64: In the evaluation of the difference
Page 65 and 66: Heat source I RT-Lab II Specimen Ch
Page 67 and 68: Thermal conductivity [W m -1 K -1 ]
Page 69 and 70: silicon glue epoxy probe hole Figur
Page 71 and 72: Computational modelling of temperat
Page 73 and 74: 1 2 3 EXT. INT. 5-15 50-60 375 5 Nu
Page 75 and 76: Fig. 4 shows a comparison of the re
Page 77 and 78: Envelope D Figs. 14, 15 present the
Page 79 and 80: Application of computational modell
Page 81 and 82: Table 2: Basic material characteris
Page 83: Temperature [K] 320 300 280 260 240
Page 87 and 88: Nowadays, most of concrete building
Page 89 and 90: Figure 2: Ceramic dessicator plate
Page 91 and 92: dessicators are decreased by the pe
Page 93 and 94: The surface water vapour diffusion
Page 95 and 96: where h is the Planck constant and
Page 97 and 98: (a) (b) Figure 2: Schematic picture
Page 99 and 100: [7] BLUM, V.; HART, G. L. W.; WALOR
Page 101 and 102: Analysis of moisture hysteresis of
Page 103 and 104: The water content during scanning b
Page 105 and 106: All analysed cellulose based materi
Page 107 and 108: Thermodilatometry of ceramics using
Page 109 and 110: of the dilatometric cell with the s
Page 111 and 112: thermal expansion / % 2 1,5 1 0,5 0
Page 113 and 114: [8] KAMSEU, E. ; LEONELLI, C. ; BOC
Page 115 and 116: heating, the temperatures were meas
Page 117 and 118: temperature difference [°C] 140 12
Page 119 and 120: temperature difference [°C] 180 16
Page 121 and 122: [4] ČÍČEL, B. - NOVÁK, I. - HOR
Page 123 and 124: space and the crystallization press
Page 125 and 126: 20 mm face to the penetrating KNO3
Page 127 and 128: Cb [kg/m 3 (sample)] 1800 1600 1400
Page 129 and 130: D [m 2 /s] 1.0E-03 1.0E-04 1.0E-05
Page 131 and 132: Thermomechanical modelling of matur
Page 133 and 134: ε ε (velocity rates) a x , t . By
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ε ε w v The process of redistribu
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Conclusion In this paper we have br
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most popular among direct technique
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• Closed pores (not available for
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espective volume of inclusions frac
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Summary Among the indirect methods
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Thermal, hygric and salt‐related
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The water vapor diffusion coefficie
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Thermal properties Thermal conducti
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On the other hand, apparent moistur
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Thermal conductivity.. [Wm -1 K -1
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Properties of innovative materials
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or hygrothermal analysis of buildin
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where Da is the diffusion coefficie
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The bending and compressive strengt
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moisture diffusivity which was caus
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Abstract: Thermal conductivity in d
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, (5) where λ is thermal conductiv
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4.Measured values and calculation I
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Acknowledgements This research has
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3 Results During heating, the struc
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Acknowledgment This work was suppor
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mixture by short mixing, the mixtur
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detected by MIP and thus the intrus
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diffusion. The general Arrhenius eq
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Thermal conductivity measurement of
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S s o 2 4 4 λ ∇ T = wεσ ( T
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steel (20 W m ‐1 K ‐1 ) is arou
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significant larger cross‐section.
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Water and heat transport properties
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The open porosity ψ0 [%], bulk den
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Table 3: Basic material parameters
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Acknowledgements This research has
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comparison of results we can determ
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specimen and heat source R at infin
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6.E-04 4.E-04 ΔU (V) 2.E-04 0.E+00
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[3] KUBIČÁR Ľ. Pulse method of m
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silicate binders as partial replace
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Table 2. Mechanical properties HPC
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HPC Table 5. Water transport proper
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The results obtained for using high
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aerospace engineering, cryogenic en
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4 ⎡ ′ ⎤ Δθ( t) = ⎢ l ∫
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Alloy Components Weight Percent, [%
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Figure 8: Final results of the ther
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Figure 11: Preliminary results of t
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In case of the FeNi35, FeNi39 and F
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Experimental Methods Compressive st
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Type of mixture Water transport pro
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Thermal properties The thermal para
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Identification of Some Thermophysic
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Physical model of the direct proble
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2 ( λ − Bi) sin( λ) − 2λ Bic
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To calculate the sensitivity coeffi
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symmetry of the specimen when the t
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Figure 5: View of experimental setu
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During the inverse calculations the
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temperature dependence for the blac
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4. Conclusions The results of the t
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cross‐planar direction applying s
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3. Thermal diffusivity identificati
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Table 2: Effect of the convective h
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[2] BODZENTA, J.; BURAKA, B.; NOWAK
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doc. Ing. Jiří Vala, CSc. Brno Un
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