The effects of shrinkage-reducing admixtures used in self-compacting concrete on its strength and durability

Abstract

This study explores the effects of shrinkage-reducing admixtures (SRA) used in self-compacting concrete (SCC), a specific type of concrete which is gradually receiving widespread use, yet to be improved to the desired properties and expected to replace traditional concrete in the future, on its strength and durability. In this study, SCC mixtures with and without (reference) different SRA dosages were produced to define the optimum SRA utilization rate in SCC mixtures. After deciding the SRA dosage to be used in mixtures, properties of reference and SRA-added SCC mixtures were evaluated by focusing mainly on the workability, strength and durability properties after subjected to either direct water submersion or cyclic Na2SO4 solution. As a result of the experimental program, it was concluded that the presence of SRA has adverse effects on the mechanical properties of SCC specimens although these effects are not dramatic regardless of the harshness of environmental exposure. The influence of SRA addition on fresh-state properties was also minimal so that the workability of reference and SRA-added SCC mixtures were found to be similar. Occurrence and further development of both drying and restrained shrinkage were substantially restricted with varying rates when SRA was incorporated in SCC mixtures. Overall, this study concludes that with a proper selection of SRA dosage, SCC mixtures performing well even under very hazardous environments can successfully be produced and be taken advantage of without sacrificing much of workability and/or mechanical properties and risking the occurrence and further development of shrinkage-originated cracking. (C) 2018 Elsevier Ltd. All rights reserved.