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Title |
Autogenous Shrinkage of Cement Paste Considering Disjoining Pressure in Thin Adsorbed Region
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Keywords |
분리 압력 ; 모세관 압력 ; 자기수축 ; 흡착영역 ; 시멘트페이스트 |
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Abstract |
Meniscus, adsorbed layer thickness, capillary pressure and disjoining pressure was deduced in extended meniscus region in cement paste pore by hydrostatic equilibrium. From the results, the relationship between pore size and adsorbed layer thickness could be derived and adsorbed layer thickness represents 0.299~2.700mm according to pore size 1mm~1㎛. Especially, disjoining pressure rapidly Increased in less than 10 nm pore size according to adsorbed layer thickness. Therefore, it is interpreted that autogenous shrinkage of cement paste is highly increases in formation of less than 10 nm pore size. Predictions of autogenous shrinkage in cement paste considering driving force for autogenous shrinkage with capillary pressure and disjoining pressure was low in comparison with experiment values between 1~4 days and high in later period. These tendency could be thought that pore damage by mercury injection in early age makes shrinkage driving force underestimate and assumption for unsaturated independent pore makes overestimate. These interactions might be needed corrections considering on hydration or pore replacement model.
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