ABSTRACT
The use of manufactured sands in the production of mortars has been increasing in the last years, since the natural sand deposits are becoming increasingly scarcers and the exploitation of sand generates high environmental impact. In this sense, the objective of this work is to verify the influence of manufactured sands from different origins and mineralogies on the properties of rendering mortars in the fresh state. Based on an extensive characterization of aggregates from different lithological sources, the research aimed to assess which sand parameters explain better the mortar behaviors of consistency and bulk density. The study was performed with five sands: one natural sand and four manufactured sands originated from rocks of different lithologies (granite, dolomite, mica-schist and quartzite). In addition to the particle size characterization and the determination of the physical indices of sands, a morphoscopic analysis and a petrographic analysis were also carried out as well as the determination of internal friction angle obtained from direct shear test, used for soils. To verify the interference of sand characteristics on the mortar properties in fresh state, it was employed a mix proportion 1: 1: 6 (Portland cement:lime:sand, by volume), and it was performed the tests to determine the consistency index in ABNT table (flow table), the cone penetration (ASTM) and the bulk density. The main conclusions point out that the porosity (voids among particles and sand grains) and the apparent dry density of sand are the best parameters to explain the variation of mortars consistency and bulk density. This is explained by the change imposed on the paste volume of mortars due to the voids volume left by the sand grains arrangement.
Keywords:
mortar; sand; consistency; bulk density; apparent dry density
