Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Performance of unprotected aramid fibers in prestressed glass concrete
In the presented study continuous aramid fibers were used to prestress thin sheets made of Portland cement based mortar, which contained glass as the exclusive form of aggregate (glass concrete). The hydroxide content of the cement system is critical at all stages of the hydration process, not only because of the eventual formation of harmful ASR gel due to the highly reactive glass aggregate, but also because of the possible hydrolysis of Aramid fibers in a highly alkaline environment. The Aramid fibers were tensioned up to 20% of their ultimate strain capacity to generate prestress levels up to 14 MPa. On the one hand prestressing was found to greatly enhance the mechanical performance and durability of thin sheets, whereas on the other hand it increased the vulnerability of the polymeric fibers to chemical attack. It was observed that a significant amount of force in the roving system was lost, but only during the first few hours of hydration. A tensile force of 90% of the initial load remained afterwards, without further losses. Possible mechanisms are discussed, which could explain the observed behavior. It is suggested that tensioned Aramid fibers are chemically more compatible with Metakaolin modified concrete systems than with regular Portland cement based matrixes.
Performance of unprotected aramid fibers in prestressed glass concrete
In the presented study continuous aramid fibers were used to prestress thin sheets made of Portland cement based mortar, which contained glass as the exclusive form of aggregate (glass concrete). The hydroxide content of the cement system is critical at all stages of the hydration process, not only because of the eventual formation of harmful ASR gel due to the highly reactive glass aggregate, but also because of the possible hydrolysis of Aramid fibers in a highly alkaline environment. The Aramid fibers were tensioned up to 20% of their ultimate strain capacity to generate prestress levels up to 14 MPa. On the one hand prestressing was found to greatly enhance the mechanical performance and durability of thin sheets, whereas on the other hand it increased the vulnerability of the polymeric fibers to chemical attack. It was observed that a significant amount of force in the roving system was lost, but only during the first few hours of hydration. A tensile force of 90% of the initial load remained afterwards, without further losses. Possible mechanisms are discussed, which could explain the observed behavior. It is suggested that tensioned Aramid fibers are chemically more compatible with Metakaolin modified concrete systems than with regular Portland cement based matrixes.
Performance of unprotected aramid fibers in prestressed glass concrete
Vilkner, G. (Autor:in) / Meyer, C. (Autor:in)
2004
8 Seiten, 5 Bilder, 1 Tabelle, 18 Quellen
Aufsatz (Konferenz)
Englisch
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