Properties of fresh and hardened concrete

SCC with crushed aggregate

Fig. 1 Types of coarse aggregate used (selection).

$Fig. 2 Results of roughness measurement by laser double triangulation sensor for basalt chips of fraction 8/16 mm, a) Segment of the measurement range captured, b) image of an individual aggregate particle, c) Surface contour line of this aggregate particle.$

Fig. 2 Results of roughness measurement by laser double triangulation sensor for basalt chips of fraction 8/16 mm, a) Segment of the measurement range captured, b) image of an individual aggregate particle, c) Surface contour line of this aggregate particle.

Fig. 3 Flow cone efflux times of the SCC with typical and increased coarse aggregate contents.

Fig. 4 Slump flow times with J-Ring of the SCC with typical and increased coarse aggregate contents.

Fig. 5 Blocking heights of the SCC with typical and increased
coarse aggregate contents.

Fig. 6 Temporal development of the compressive strengths.

Fig. 7 Temporal development of the tensile splitting strengths.

Fig. 8 Temporal development of the e-moduli.

 In self-compacting concretes (SCC), round particles are frequently used as coarse aggregate. These are expected to be of advantage, in particular as regards an improved work-ability. The tests presented in this article demonstrate that the manufacture of SCC with a high content of crushed aggregate and good workability is possible. In addition it was shown that the use of crushed aggregate, instead of gravel, can improve the strength and deformation properties of the concrete.

The fresh concrete properties of self-compacting concretes (SCC) are considerably influenced by the choice of coarse aggregate. The principal parameters are in this context the quantitative content of the concrete as well as the particle geometry and roughness. But hardened concrete properties result from this as well and/or are determined via these parameters. Knowledge of these interrelated aspects thus offers the possibility to directly influence the properties of fresh and hardened concrete through the choice of coarse aggregate.

The following article presents, firstly, possibilities for...