Characteristics of CFRP-concrete interface subjected to cold region environments including three-dimensional topography

摘要

This paper presents an experimental program to examine the interfacial behavior of carbon fiber reinforced polymer (CFRP) composite sheets bonded to concrete substrate when subjected to cold region environments. A total of 53 specimens are exposed to 150 cycles of freezing-wet-dry and wet-dry as well as constant low temperature effects ranging from 0 ℃ to -30 ℃ for 2000 h. A novel sensing technology, based on three-dimensional micro-topography, is presented using an instantaneous laser scanner to quantitatively examine the characteristic size of damage-band along the CFRP-concrete interface. Test results show that the effects of freezing-wet-dry are more detrimental than those of wet-dry, in particular noticeable when the temperature is below - 20 ℃. The low temperature increases the local brittleness of the interface and thus stress-softening is not observed for the specimens subjected to freezing-wet-dry. The specimens in wet-dry, however, exhibited such softening responses. The characteristic size of damage-band along the CFRP-concrete interface is found to be 14.5 mm; however, the size changes when the environmental loads are applied. Damage concentrations are observed in the damage-band with the presence of low temperature effects.