Title: Development of Shrinkage Reduced Self Compacting Concrete

Author(s): A.B. Eberhardt and J. Kaufmann

Publication: Symposium Paper

Volume: 235

Issue:

Appears on pages(s): 13-30

Keywords: drying shrinkage; free shrinkage; restrained shrinkage; ring test; self-compacting concrete; shrinkage reducing admixture

DOI: 10.14359/15845

Date: 3/22/2006

Abstract:
It is well known that, in comparison with normal (usual) concrete, self compacting concrete (SCC) shows higher shrinkage because of the higher volume of binder, inevitable for achieving high fluidity and a good cohesiveness of the fresh concrete. It is necessary to avoid crack formation caused by drying or autogenous shrinkage as cracks could serve as flow paths and ingression zones for gases and salts or favour leaching. In order to diminish this negative effect of SCC’s, mixture concepts for the formulation of a shrinkage reduced SCC were developed. Different factors influencing the shrinkage behaviour are discussed. The effect of replacing cement by high volume of pozzolanic or inert additives as well as the effect of different shrinkage reducing admixtures (shrinkage reducing agents - SRA) was examined. Furthermore an optimization of the grain size distribution was evaluated. The measuring setup consisted of different methods, most important the measurement of free and restrained shrinkage (ring test) on mortar and concrete specimens. It could be shown, that through a significant reduction of the cement amount, accompanied by an effective shrinkage reducing admixture a massive shrinkage reduction of SCC’s in the range of 50% to 60% can be achieved.