Authors
1
Department of Geology,Yazd University, Yazd,, Iran
2
Department of Geology, Faculty of Earth Sciences, Shahid Chamran University of Ahvaz, Ahvaz, Iran
3
Assistant Professor, Department of Geology, Yazd University, Yazd, Iran
4
Master's degree, Department of Geology, Yazd University, Yazd, Iran
Abstract
Abrasion and chemical durability of ballast aggregates are considered to be essential characteristics that affect the performance of structures such as railway. Los Angeles abrasion index and weight loss in magnesium sulfate solution are among the most important parameters of rocks that are usually used in engineering designs. These parameters are largely influenced by the texture characteristics of rocks. In this research, seven types of extrusive igneous rocks were investigated in order to evaluate the correlation of textural indices with mineralogical, physical and mechanical characteristics. Engineering characteristics including density, porosity, point load strength, Los Angeles abrasion index and weight loss of magnesium sulfate were measured in the laboratory for the samples. Also, the thin section photographs of the samples were analyzed in ImageJ and JMicroVision image analyzer softwares. Textural indices (texture coefficient, elongation index, circularity index, solidity index and ferret diameter index) were calculated based on the image analysis for all the samples. Finally, the relationships between these indices with mineralogical and physical-mechanical characteristics of the rocks were evaluated. The results showed that non-dimensional minerals such as feldspar and mafic minerals (amphibole, pyroxene and biotite) have a relatively significant relationship with elongation index. Also, very strong linear relationships were observed between Los Angeles abrasion index (R2 = 0.90) and weight loss of magnesium sulfate (R2 = 0.877) with texture coefficient. Finally, based on the results, it is inferred that textural indices such as textural coefficient can be used in estimating the durability characteristics of aggregates with high reliability.
Keywords
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