Microdureity and abrasive wear of silicatic coating rocks


The hardness of a material is function of several parameters in a multivariate and interdependent universe. This study used statistical analysis following the multiple regression method between Knoop hardness and abrasive wear test in the Amsler machine, aiming to determine the eventual relation among these properties regarding durability prediction inuse situation, particularlyin high foot traffic areas. The Knoop hardness is a rock attribute determined by the microscopic indentation from a diamond tool on its surface. It is calculated as the ratio between the area of indentation and the applied load. The Amsler abrasive wear is a test which utilizes quartz-rich sand and the wear is measured, in millimeters, as the average thickness reduction after a 1.000-meter path under a 66 N load. Sixteen aluminous-silicatic rocks (containing 35% to 0% of quartz), including granites, monzonites, gneiss and others, commercially designated as “granites”, all characterized in the São Paulo State Dimension and Covering Stones Catalog (Frascá, 2000), were selected for this study. The results, as expected, indicated that the Knoop hardness and the Amsler abrasive wear tend towards an inverse proportionality, or as higher is the hardness, lower is the wear. In the studied samples, the best correlation between the parameters of Knoop hardness and Amsler abrasive wear was0,56 (R2), obtained by multiple linear regression. The Knoop hardness, particularly the average value, tends to higher values as the quartz content increases. Relatively to the quartz grain-size, it was observed a tendency to the increase of hardness, especially HK25, with the increase in quartz grain-size. Considering the main forming minerals (quartz, plagioclase and K-feldspar) content, in a multiple linear regression, the Amsler abrasive wear can be predicted with a slightly better correlation than Knoop hardness.

QUITETE, Eduardo Brandau, NAVARRO, Fabiano Cabañas; FRASCÁ, Maria Heloisa Barros de Oliveira. Micreodureza e desgaste abrasivo de rochas silicatadas de revestimento. Brazilian Journal of Development, v.6, n.7, p. 51516-51527, jul., 2020.

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