High-Performance Binders with Reduced Autogenous Shrinkage on the Basis of Fine Cement

Abstract

Because of their low water/cement ratio, high-performance concretes have not only a high density but also a great tendency to chemical shrinkage deformation (autogenous shrinkage) as a result of "self desiccation". The autogenous shrinkage increases if silica fume is added. Theoretical calculations show that the usual addition of silica fume leads to an increase in total porosity, and hence to a deterioration of the packing density of the binder mixture, while at the same time raising the specific surface area of the dry powder. On the other hand, replacement of cement by optimized fine cements improves the theoretical packing density in the binder, even though with a lower increase in the specific surface area. Investigations carried out on hardened cement paste made from fine cements have shown that this leads not only to higher density but also to lower autogenous shrinkage values.