Strength Variability and Its Relationship with Microstructure of Coarse Granite Aggregates
A. A. Bastos, N. V. Silva, J. P. Monticelli, M. M. Futai, L. M. Tavares, and S. C. Angulo
Appears on pages(s):
coarse aggregates; microstructure-strength relationship; rock weathering; strength variability; water absorption
The present work investigated the relationship between strength variability and the microstructure of granite aggregates. The strength of particles was determined by an improved point load test. The microstructure and composition were evaluated by tactile-visual analysis, water absorption, X-ray diffraction, and petrographic analysis with the calculation of the micropetrographic index. The weathering grade was estimated according to tactile-visual analysis and the relationships between strength, micropetrographic index, water absorption, and literature data. The results demonstrated that the relationship among the micropetrographic index and strength is more defined than that with water absorption. The strength appears to reduce with the presence of minerals with well-defined cleavage and orthoclase feldspar phenocrystals observed through petrographic analysis, but is not quantified. Low strength seems to be related to higher water absorption and weathering grade. Additional work, however, will be required to confirm these findings through quantification of the proportion of both minerals with cleavage and feldspar phenocrystals.