Uniformity Of Scc Properties Cast In Vertical Column

摘要

This experimental work examines the homogeneity of self-compacting concretes in vertically cast columns. Eight different concretes were used, four self-compacting (SCC) and four normally vibrated (NVC). The distribution of pore sizes, the compressive strength, the rebound hammer and the bond strength were determined at different locations on 1500 mm high columns. It was found that SCCs have a slightly more uniform porous microstructure along the height. Moreover, up to 100 cm in height the four SCC mixes display a strength distribution comparable to that obtained with control concretes. For greater heights, the loss of strength is lower in SCCs (3·91%) than in NVCs (9·35%). Unlike NVCs, for SCCs the water/cement ratio does not seem to have a significant influence on the variation of strength with height. The top-bar effect is much less marked in SCC, and therefore a change in the factor that takes into account this effect in the formulae used for calculating the anchorage length of the reinforcement is proposed for these concretes.