Incorporation of CrusHed Sands and Tunisian Desert Sands in the Composition of Self Compacting Concretes Part I: Study of Formulation

This paper examines the incorporation of the crushed sand (CS) and desert sand (DS) in the formation of self compacting concrete (SCC). These sands have been substituted for the rolled sand (RS), which is currently the only sand used in concretes and which is likely to run out in our country. DS, which comes from the Tunisian Sahara in the south, is characterized by a tight distribution of grains size. CS, a by-product of careers containing a significant amount of fines up to 15%, is characterized by a spread out granulometry having a maximum diameter of around 5mm. These two sands are considered as aggregates for the SCC. This first part of the study consists in analyzing the influence of the type of sand on the parameters of composition of the SCC. These sands consist of several combinations of 3 sands (DS, CS and RS). The method of formulation of the adopted SCC is based on the filling of the granular void by the paste. The CS substitution to the RS made it possible, for all the proportions, to decrease the granular voids, to increase the compactness of the mixture and to decrease the water and adding fillers proportioning. These results were also obtained for a moderate substitution of DS/CS (< 40%) and a weak ratio of DS/RS (20%). For higher proportions, the addition of DS to CS or RS did not improve the physical characteristics of the SCC granular mixture.