Physico-Mechanical Properties of Mortar Made with Binary Natural Fine Aggregates (Dune Sand and Crushed Sand) with and without Chemical Admixture

This experimental study investigates the effect of using binary natural fine aggregates (dune sand and crushed sand) on mortar. This method is utilized to modify the particle size distribution of various sands used in mortar. For this investigation, two sands were used: a dune sand (DS) and crushed sand (CS) at different proportions in mortar. The effect of the quality and grain size distribution of natural fine aggregates (DS ad CS) on the physical properties of binary sand confected (apparent or bulk density, absolute or gravity density, porosity, fineness modulus, particle size distribution and water absorption). The properties of fresh and hardened mortar were also analysed. The results obtained showed that the mechanical strength of mortar depends on the nature and particle size distribution of sand studied. This study shows the potential of this method to make mortar with binary sand (dune and crushed fine aggregates) in order to improve the physical properties of sand. The increase in the quantity of mixing water generated by addition of quarry waste was modified by the addition of a superplasticizer or water reducing admixture (Medaflow 30) what led to the improvement of the physical and mechanical properties of the mortar. The inclusion of crushed sand (CS) at replacement levels of 40 % to 50% resulted in a increase in the mechanical strength of the mortar. However, the improved performance was observed when quarry waste as fine aggregate was used in presence of chemical admixture (1% of Medaflow 30).