prediction of long-term slake durability of clay-bearing rocks

a research program was conducted on different clay-bearing rocks selected from the ilam, sarpol-e zahab and tajarak regions (iran) to predict their slaking characteristics. the new durability apparatus (nested mesh drums) separates disintegrated particles varying from > 25.4 to < 2 mm as the drums were rotated. on the basis of the particle size distribution, the disintegration ratio (dr) was used to evaluate the rock durability. a concept was proposed to describe the rock slaking characteristics under the slake durability test cycles, by using the difference in the dr values between the adjacent (δdr) and backward (n*) cycles. this allows the estimation of the rock durability as it is subjected to a larger number of test cycles, and hence the prediction of the effects of weathering processes. this prediction provides an effective approach when data are limited or inaccessible. therefore, a new classification system is introduced for rock durability assessment. the test results show that the gurpi-limey marls (g-2, g-3) and the pabdeh-marly limestone (p-3) are classified as moderate to high durability rocks