Time-dependent deformations of limestone powder type self-compacting concrete

Due to its different mix composition (e.g. use of superplasticizer, lower water/powder ratio (W/P) and higher paste volume) and its denser microstructure, different mechanisms and magnitudes concerning the time-dependent deformability, i.e. shrinkage and creep, hold for limestone powder type self-compacting concrete (SCC). For this reason, experimental investigations concerning the shrinkage and creep behaviour of 7 limestone powder type SCC mixtures and 1 reference, traditionally vibrated, concrete mixture (TC1) are performed. The water/cement ratio (W/C), cement/powder ratio (C/P), aggregate type and cement type are studied. The experimental data have been used to verify the accuracy of the CEB-FIP Model Code 1990 (MC-90) in terms of long-term deformations. Test results revealed generally higher shrinkage and creep deformations for the SCC mixtures compared with the TO mix. However, whereas the shrinkage deformations are underestimated by MC-90 the creep and overall behaviour of the limestone powder type SCC mixtures are rather well predicted by the same model. In order to properly predict the time-dependent behaviour of limestone powder type SCC in cases of concrete structures (highly) sensitive to shrinkage and creep, a modification of the MC-90 in terms of the total shrinkage strain prediction is proposed by the authors. For creep, test results revealed that the MC-90 creep coefficient prediction could remain unmodified for limestone powder type SCC application. (C) 2008 Elsevier Ltd. All rights reserved.