Use of limestone sands and fillers in concrete without superplasticizer

This paper deals with the effects of the amount of limestone fillers with respect to the rheological, mechanical, and dimensional properties of concretes without superplasticizer. These concretes were made with two limestone coarse aggregates and one limestone sand from the same quarry, in order to avoid any artifact. Five sand containing fillers rate between 1.8% and 24% – representative rates of the categories defined in the EN 12260 norm for aggregates for concretes – were produced by mixture of original sand with its fine fraction or its grained fraction extracted beforehand by washing. The concretes were mix designed with the BetonlabPro2 software, whose algorithms take into account the presence of the limestone fillers. The experimental results show that the concretes containing from 100 to 150 kg/m3 limestone fillers often present optimal properties, with equal consistency. But, higher quantities of fillers do not deteriorate significantly the properties of the concretes, even if their packing density decreases. This behavior is explained not only by the binding effect allotted to the limestone fillers, but also by an improvement of the paste-aggregates bond.