Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Influence of alkalies on hygral shrinkage of cementitious composites
Homogeneity of the structure and of properties is a major advantage of self-compacting concrete. Homogeneously distributed permeability leads in practice to more durable structural elements. SCC is usually produced with a comparatively high cement content. As a result of this characteristic composition shrinkage and shrinkage induced cracking may turn out to become a serious problem. Crack formation may in fact counterbalance the advantage of improved homogeneity. For this reason it is particularely important to use all means to reduce shrinkage of SCC. It has been shown that shrinkage can be reduced considerably by applying a cement with low alkali content. This type of cement combines two beneficial effects: (1) hygral gradients may be reduced as the W/C can be lowered and (2) the disjoining pressure in the nano-structure of C-S-H is reduced. This second effect reduces shrinkage and is similar to the swelling pressure of clays as influenced by the chemical composition of the pore solution. Recent experimental results obtained by Weimann and Li on ECC confirm these findings.
Influence of alkalies on hygral shrinkage of cementitious composites
Homogeneity of the structure and of properties is a major advantage of self-compacting concrete. Homogeneously distributed permeability leads in practice to more durable structural elements. SCC is usually produced with a comparatively high cement content. As a result of this characteristic composition shrinkage and shrinkage induced cracking may turn out to become a serious problem. Crack formation may in fact counterbalance the advantage of improved homogeneity. For this reason it is particularely important to use all means to reduce shrinkage of SCC. It has been shown that shrinkage can be reduced considerably by applying a cement with low alkali content. This type of cement combines two beneficial effects: (1) hygral gradients may be reduced as the W/C can be lowered and (2) the disjoining pressure in the nano-structure of C-S-H is reduced. This second effect reduces shrinkage and is similar to the swelling pressure of clays as influenced by the chemical composition of the pore solution. Recent experimental results obtained by Weimann and Li on ECC confirm these findings.
Influence of alkalies on hygral shrinkage of cementitious composites
Beltzung, F. (Autor:in)
2003
9 Seiten, 6 Bilder, 9 Quellen
Aufsatz (Konferenz)
Englisch
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