Assessing the Behavior of Clay-Bearing Rocks Using Static and Dynamic Slaking Indices

Clay-bearing rocks are characterized by a wide variation in engineering properties and their resistance to short term weathering due to wetting and drying phenomenon. In this study, a research study was performed on different clay-bearing rocks selected from the Ilam and the Tajarak regions (Iran) to assess suitability of the static and dynamic standard slaking tests. Also in this paper, in order to estimate durability of the clay-bearing rocks, some physical-chemical properties were used in form of multiple linear regression analyses in relation to the static and dynamic slaking indices. The test results from the static and dynamic standard slaking tests showed that the materials retained in the 2 mm mesh drum consists of disintegrated particles varying in diameter from 2 to 25.4 mm. To achieve a more realistic evaluation of the disintegration properties of rock samples after each wetting-drying cycle, a sieve analysis approach is therefore more appropriate. Comparison of the multiple linear regressions between the slaking indices and physical-chemical properties showed that the disintegration ratio could characterize the durability behavior of the rock samples in both the static and dynamic states. Also, the results indicated that the static slaking index (I-s) was more acceptable for predicting the behavior of clay-bearing rocks than the dynamic durability index (I-d).