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Wyszukujesz frazę "freezing and thawing" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Application of SEM to Analysis of Permeability Coefficient of Cohesive Soils
Autorzy:
Kozłowski, T.
Kurpias-Warianek, K.
Walaszczyk, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/241142.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
cohesive soils
permeability coefficient
SEM
NIA
cyclic freezing and thawing
Opis:
A series of experiments on samples of five clayey soils gave evidence that cyclic freezing and thawing significantly affects the permeability coefficient. An attempt to analyze these changes on base of the Scanning Electron Microscopy SEM photographs of microstructures has been made. A simplistic equation (Eq. 11) has been drawn, describing the permeability coefficient as a function of hydraulic radius and pore area. An approach to determine the permeability coefficient by Eq. (11) on base of SEM photographs, in which the pores were identified manually, yielded results comparable to the Falling Head Test (FHT). However, since the identification of pores in SEM photographs seems the critical point of the method, the Numerical Image Analysis (NIA) has been applied. The procedure of finding the optimum threshold Topt has been described, based on minimization of the deviation ?ki,j, calculated as the absolute value of the difference kSEM,i,j and kFHT,j, i.e. the permeability coefficients determined by the SEM analysis and FHT, respectively. It has been proved that the optimum threshold values can be described as a function of image parameters, i.e. mean grey level Lmean and standard deviation σ n.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2011, 58, 1-4; 47-64
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effects of pore structure on freezing and thawing deterioration
Autorzy:
Klemm, A.J.
Wieloch, M.
Klemm, P.
Powiązania:
https://bibliotekanauki.pl/articles/362433.pdf
Data publikacji:
2005
Wydawca:
Instytut Fizyki Budowli Katarzyna i Piotr Klemm
Tematy:
trwałość
zamrażanie-odmrażanie
durability
freezing and thawing
microstructure of cement-based materials
Opis:
Manufacturing of concrete resistant to freezing and thawing requires an in de understanding of the mechanisms triggering deterioration. Despite numerous attempts, a definitive and fully explanatory model has yet to be formulated. This paper presents part of study which analyzes influence of pore structure of cement-based matrix on the frost durability of Ordinary Portland Cement mortar is analysed. An empirical investigation was carried out on five air-entrained and one non-air- entrained mortar (with water-to-binder (W/B) ratio 0.4) subjected up to 732 freezing/thawing (Frr) cycles. Various concentrations of air-entraining admixture were used to differentiate the pore-structure of mortar. The examination of the microstructure and composition of the cement paste was performed by means of Scanning Electron Microscope (SEM) and Mercury Intrusion Porosimetry (MIP). Presented results demonstrate the magnitude of alterations to pore configuration due to pure freezing/thawing and its effect on the mechanical characteristics (compressive/flexural strength). Finally, on the grounds of apparent transformation. a generic pore size distribution of frost resistant cement-matrix is proposed.
Źródło:
Fizyka Budowli w Teorii i Praktyce; 2005, T. 1; 190-200
1734-4891
Pojawia się w:
Fizyka Budowli w Teorii i Praktyce
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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