A new sampling approach developed with aggregates on the investigation of the effects of the sample’s shape and size for slake durability test

The slake durability test is one of the most common laboratory tests used to predict the durability of rocks against disintegration. In literature, a lot of studies have reported a series of disadvantages that occur on the slake durability test. However, there are not enough numbers of studies written about the difficulties of preparing rock lump samples according to the current standards of International Society for Rock Mechanics and Rock Engineering (ISRM). Therefore, in regard of overcoming the difficulties encountered during sampling process of slake durability test, this study aims to investigate the effects of the sample’s shape and size on the slake durability test and develop a new sampling method that is both simple and efficient for the test conductors through the obtained data. In this study, the six different rock types including three types of volcanic tuffs, weathered andesite, micrite limestone and clayey limestone were used to carry out the slake durability test with the samples prepared in rounded lump, aggregate and disc shapes. The correlations based on the slake durability test results of the sample’s different shapes and sizes reveal that there is a correspondence notably between slake durability indices obtained from the standard and aggregate samples. •The effects of the shape and size of the sample on the slake durability test were investigated.•Standard, aggregate, and disc-shaped specimens were used to perform the slake durability test.•Aggregate shape specimens can be used efficiently instead of the standard specimen.•It is more appropriate to use aggregate shape samples to determine the durability of soft rocks more precisely.