The interfacial bond-slip behavior of I-section steel and reactive powder concrete at high temperatures

Abstract

The paper presents the interfacial bond-slip behavior between I-section steel and reactive powder concrete at high temperatures. Push-out test was carried out on twenty-two specimens at high temperatures by considering the impact of the maximum heating temperature, concrete cover thickness, steel ratio, stirrup ratio, interface bonding position and anchorage length of I-section steel. The test results show that the ultimate bond stress of the specimen decreases with the increase of temperature and the ultimate bond stress of the specimen at 600 °C is only 7.8% of that at ambient temperature (20 °C). The ultimate bond stress of specimens drops greatly before 250 °C, but the drop range decreases obviously when the temperature exceeds 250 °C. At the same high temperature (250 °C), the ultimate bond stress of the specimen increases with the increase of concrete cover thickness and stirrup ratio. When the concrete cover thickness increases from 40 mm to 80 mm, the ultimate bond stress increases by 64.3%. When stirrup ratio increases from 0.17% to 0.66%, the ultimate bond stress increases by 37.9%. Based on the data of push-out tests, the bond-slip constitutive model of I-section steel and reactive powder concrete at high temperatures is proposed, which provides constitutive model for the numerical simulation analysis of steel reinforced reactive powder concrete at high temperatures.