The Influence of the Chosen Type of Form Lubricator in the Form for Cement Paste with Fly Ash on the Fracture Process Zone

摘要

This paper is focused on the crack growth of specimens made of cement paste with fly ash in mode II. Three prescriptions were made for testing in mode II, during the making of the specimen air bubbles arose at the bottom of the specimen that was lubricated with oil. These little caverns can have an influence on the growth of the cracks in the fracture process zone. On the other side, on the specimens that were lubricated with a wax, no caverns were observed. There are complex mechanisms of crack growth in the fracture process zone. The caverns or inertial elements have a fundamental effect on the success of the real tests in mode II. The specimens lubricated with wax have a 50 % higher successful running of the test than those, whose forms were lubricated with the oil.