Zmiany mikrostruktury i właściwości resztkowe kompozytów cementowych zbrojonych włóknami poddanych działaniu wysokich temperatur

Keppert, M.; Vejmelková, E.; Švarcová, S.; Bezdička, P.; Černý, R.

Artykuł - szczegóły

Tytuł artykułu

Zmiany mikrostruktury i właściwości resztkowe kompozytów cementowych zbrojonych włóknami poddanych działaniu wysokich temperatur

Autorzy

Keppert M. , Vejmelková E. , Švarcová S. , Bezdička P. , Černý R.

Wybrane pełne teksty z tego czasopisma

http://www.cementwapnobeton.pl/

Identyfikatory

Warianty tytułu

Microstructural changes and residual properties of fiber reinforced cement composites exposed to elevated temperatures

Języki publikacji

Abstrakty

Podgrzanie do wysokiej temperatury powoduje nieodwracalne zmiany mikrostruktury kompozytów cementowych powodujący pogorszenie ich właściwości mechanicznych i trwałości. W pracy zbadano wpływ wysokich temperatur, sięgających do 1000oC, na skład fazowy i mikrostrukturę czterech różnych rodzajów zbrojonych włóknami kompozytów cementowych, przy zastosowaniu rentgenografi i, porozymetrii rtęciowej oraz metody BET. Właściwości resztkowe określono w oparciu o wytrzymałość na zginanie i pozorną dyfuzyjność wilgoci. Wyniki doświadczeń pokazują, że proces zniszczenia matrycy (spiekanie żelu i rozszerzalność kruszywa) wpływa znacznie bardziej na układ porów niż zniszczenie nietrwałych termicznie włókien. Korzystny wpływ na resztkową wytrzymałość na zginanie mają trwałe termicznie włókna, co najmniej do 600oC, jednak względne zmiany wytrzymałości kompozytów z tymi włóknami są większe. Stwierdzono, że pozorna dyfuzyjność wilgoci jest wykładniczo skorelowana z objętością porów kapilarnych.

The high temperature load causes irreversible changes in the microstruclure of cementitious composites resulting in decrease of their mechanical performance and durability. In this paper, the effect of elevated temperatures up to 1000°C on the mineralogical composition and microstructure of four different types of fiber reinforced cement composites is evaluated by means of X-ray diffraction analysis, mercury intrusion porosimetry and nitrogen adsorption porosimetry. The residual properties are characlerized by bending strength and apparent moisture diffusivity. Experimental results show that the degradation processes of matrix (gel sintering and aggregates expansion) influence the pore system more significantly than the degradation of thermally unstable fibers. The residual bending strength is positively affecled by the thermally stable fibers at least up to 600°C but in a relative sense the strength reduction in composites with this type of fibers is more significant. The apparent moisture diffusivity is found to be exponentially correlated by volume of capillary pores.

Słowa kluczowe

kompozyt cementowy kompozyt zbrojony włóknami temperatura wysoka mikrostruktura skład mineralny właściwości resztkowe

cement composite fibre reinforced composite high temperature impact microstructure mineral composition residual properties

Wydawca

Fundacja Cement, Wapno, Beton

Czasopismo

Cement Wapno Beton

Rocznik

2012

Tom

R. 17/79, nr 2

Strony

77--89

Opis fizyczny

Bibliogr. 36 poz., il.

Twórcy

autor

Keppert M.

autor

Vejmelková E.

autor

Švarcová S.

autor

Bezdička P.

autor

Černý R.

Department of Materials Engineering and Chemistry, Faculty of Civil Engineering, Czech Technical University in Prague, Czechy

Bibliografia

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Typ dokumentu

Bibliografia

Identyfikator YADDA

bwmeta1.element.baztech-article-BTB6-0004-0002