Estudo do comportamento mecânico à compressão e flexão em argamassas de revestimento com substituição parcial de cimento Portland por sílica da casca de arroz, cinza volante e metacaulim

Abstract

For this study, the characterization of rheological (in the fresh state) and mechanical behavior of mortar with partial replacement of Portland cement by mineral additions of rice husk silica, metakaolin and fly ash, and combinations of these mineral additions, called blends, were performed. In the study, the behavior in the fresh state was evaluated through the spreading test using the flow table. With respect to the evaluation of the mechanical properties, the tests of axial compression and flexion in the traction were carried out in three points. Finally, the numerical simulation of the composites of the mixtures was performed to analyze the results of these with the mechanical properties of axial compression. For the accomplishment of this work, a trace of mortar of coating of 8 MPa of resistance to the axial compression was used as reference and the relation water/cementing material was fixed. As for the rheological test in the fresh state through the flow table, the scattering was not significantly altered with the use of the mineral additions, and for some blends the scattering increased and, for others, it decreased. The best results in terms of axial compressive strength of the mortars were obtained for the substitutions of 5% rice husk silica and for the blends containing 5% of rice husk silica with 5% fly ash or with 10% of metakaolin. The data on compactness show that with the increment of rice husk silica, the rice husk silica tends to decrease, and, with the use of metakaolin, it tends to increase.