Estimating of the durability and weathering state of rock materials using chemical weathering indices based on cation packing value: A case study

Abstract

Weathearability and/or the performance of the building stones in service are depend heavily on mineralogical composition, fabric, especially micro-fissure properties, and weathering state of rocks material. When considering the definition of the k-value, it is possible to say that the k-value can be used for characterizing the weathering state and weatherability of a rock.

As decomposition of a mineral result in the formation of new minerals with lower k-value, the k-value of whole rocks is generally regarded as a measure of the degree of weathering. The difference between the k-value of fresh sample and the k-value of weathered sample gives the amount of chemical leaching. k- leaching index exhibits good correlations with both micro-fissure plus voids and the weathering indices representing chemical leaching. The difference between the k-value of the whole sample and the k-value of the unaltered parts of the same samples gives the amount to weathering product. Therefore the ratio of the difference to k-value of the same sample is defined as k-product index

These indices are applied on the selected weathering profiles in the Kurtun Granodiorite, NE Turkey, for the estimation of the effects of petro-chemical properties on the durability of the rock materials and weathering state. There are found the statically meaningful relationships between the static and dynamic durability indicators and these chemical weathering indices based on k-value. It is shown that k-leaching index and k-products index, defined in this study can be used to evaluate the chemical weatherability and weathered state of weathered rocks materials.