Investigations of direct shear of one-year old SFRC after exposed to elevated temperatures

Abstract

Shear investigations are important in concrete due to the nature of brittle failure of shear. Moreover, concrete structures are more prone to shear failure in case of elevated temperatures. An experimental program has been investigated herein using different amounts of steel fibres, i.e., 0, 40 and 80 kg/m3. This study is part of overall study for the PhD degree. The first phase was to test push-off specimens at 28-days. At the current study, a total of 45 push-off specimens were tested at the age of one-year after exposure to different levels of max temperatures, i.e., 20, 15, 300, 500 or 700 °C. The test is carried out at cold-state. Three LVDTs were used to measure crack slip as well as crack width. Results showed significant improvements in shear strengths as well as shear toughness by fibre content at ambient and less degree at elevated temperatures. Furthermore, crack width had generally more stiffness than crack slip, yet both fibre content and elevated temperature decrease the stiffness.