The Application of Impression Test in Creep Behavior of Mudstone Available to Purchase

Conventional creep testing requires a large number of samples to enable study of the time-dependent behavior of rocks which makes it a time consuming and inconvenient process. Build-ing models and studying mechanisms is also difficult when there are sample-to-sample variations in the microstructure, hence a localized creep testing technique which gets many data from one sample becomes attractive. Some methods such as "indentation creep test" have been used for measuring creep parameters in solid materials. It turned out that a cylindrical indenter with a flat end gives a steady state penetration velocity at constant load. This special kind of indentation creep test is called "impression creep test". This kind of creep test has been carried out by other researchers just on the salt rocks. For developing this method and extending its application for other rock types, mudstone specimens were tested. For this, an impression creep apparatus was fabricated and the tests were performed under different axial loads the results of which are discussed in the present paper. This experiment proved that the new creep test method can be applied successfully on argillaceous rocks too.