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| Avtorstvo: |
Jana ŠELIH // 1.01 Izvirni znanstveni članek
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| Leto: |
1996 |
| Citat: |
ŠELIH, Jana, SOUSA, Antonio C. M., BREMNER, Theodore W. Moisture transport
in initially fully saturated concrete during drying. Transp. porous
media, 1996, vol. 24, str. 81-106. |
| Povzetek: |
Moisture content changes
during drying were investigated in the present work. Particular emphasis was
placed on the initial stage of drying of saturated concrete, where moisture
contents are high. For this stage of drying, experimental data are lacking,
and no comprehensive theory exists to describe it. The present investigation
was performed experimentally and numerically for drying of cylinders with
one exposed end, made of normal weight and lightweight concrete with varying
water to cement ratio (w/c). The gravimetric technique was employed to
obtain the spatial distribution of moisture content. The experimental
results obtained indicate that drying of concrete becomes diffusion
controlled when the average moisture content decreases below 70 to 80 % of
the initial saturation. Typical drying rates are in the order of magnitude
of 0.18 kg/day/m2 and 0.02 kg/day/m2 for the first and the second stage of
drying, respectively. The lightweight concrete cylinders as compared to
those made of normal weight concrete exhibited higher levels of moisture
content throughout the process. At high w/c ratios, the moisture profiles
for both types of cylinders, as expected, show steeper changes with time.
Large, constant drying rates were observed both experimentally and
numerically in the beginning of the drying. The numerical model developed is
based on a generalized mathematical formulation for mass and heat transfer
in porous media, and its predictions are in agreement with the experimental
data within the uncertainty range of the input data
V članku smo
obravnavali spremembe vsebnosti vode med sušenjem polno zaščitenega betona s
posebnim poudarkom na začetni fazi šušenja, ko so vsebnosti visoke.
Eksperimentalnih podatkov za to fazo je v literaturi malo. Eksperimentalno
in numerično preiskavo sušenja smo izvedli za betonske valje različnih
dolžin. Valji so izpostavljeni sušenju na eni stranici in so narejeni iz
konvencionalnega betona in betona z lahkim agregatom. Eksperimentalno smo
ocenili vpliv vodocementnega faktorja ter dolžino nege betona na potek
izsuševanja. Razviti numerični model temelji na posplošeni matematični
formulaciji masnih in toplotnih pretokov v poroznih materialih, in njegovi
rezultati se ujemajo z eksperimentalno dobljenimi vrednostmi znotraj
intervala negotovosti vhodnih podatkov |
| Tipologija: |
1.01 Izvirni znanstveni članek |
| COBISS ID |
118375 Polni zapis iz sistema COBISS |
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Vpisal 2001/08/08 19:56
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