Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Autogenous healing properties of cement-based grouts
The ability of cement-based grouts to self-seal (autogenous sealing) was investigated on bulk grouts and in thin films of grouts. The self-sealing capabilities of the grouts were investigated with water percolating through the grout. The sealing process was studied by means of the changes in the pore structure (decrease in the pore radius and volume of pores) and changes in the rate of water flow through the grout. The rate of the reduction in the crack size appeared to be primarily dependent on the initial aperture. The hydraulic conductivity (K) of the 'porous' grouts decrease with time, but only within limits that depend on the grout's initial porosity and composition. The changes in the permeability were related mainly to changes in porosity caused by the formation of new hydration products resulting from the increase in the degree of hydration (i.e. formation of new CSH) and associated reactions (i.e. precipitation of ettringite). The decrease in K was faster and more pronounced in grouts cured for shorter periods of time and recompacted at higher densities. The water-cement ratio in the original grout did not seem to have much bearing on the changes in the microstructure and on K. The main processes responsible for the observed decrease in K are the continued hydration reaction and precipitation.
Autogenous healing properties of cement-based grouts
The ability of cement-based grouts to self-seal (autogenous sealing) was investigated on bulk grouts and in thin films of grouts. The self-sealing capabilities of the grouts were investigated with water percolating through the grout. The sealing process was studied by means of the changes in the pore structure (decrease in the pore radius and volume of pores) and changes in the rate of water flow through the grout. The rate of the reduction in the crack size appeared to be primarily dependent on the initial aperture. The hydraulic conductivity (K) of the 'porous' grouts decrease with time, but only within limits that depend on the grout's initial porosity and composition. The changes in the permeability were related mainly to changes in porosity caused by the formation of new hydration products resulting from the increase in the degree of hydration (i.e. formation of new CSH) and associated reactions (i.e. precipitation of ettringite). The decrease in K was faster and more pronounced in grouts cured for shorter periods of time and recompacted at higher densities. The water-cement ratio in the original grout did not seem to have much bearing on the changes in the microstructure and on K. The main processes responsible for the observed decrease in K are the continued hydration reaction and precipitation.
Autogenous healing properties of cement-based grouts
Onofrei, M. (Autor:in) / Roe, L. (Autor:in) / Shenton, B. (Autor:in)
AECL EACL ; 11753 ; 1-38
1997
38 Seiten, 14 Bilder, 4 Tabellen, 38 Quellen
Report
Englisch
Beton , Dichtigkeit , Dichtung , Riss , Kitt , hydraulischer Zement , Wasserundurchlässigkeit , Wasser , Wasser-Zement-Wert , hydrothermale Reaktion , Calciumaluminatsulfathydrat , Porosität , Pore , Mikrogefüge , Wasseraufnahme , Sprungausheilung , Anwendung in der Kerntechnik , radioaktiver Abfall , Kapillarität
Autogenous healing of cement paste
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Autogenous healing of thin cement based sheets
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