OPTICAL CHARACTERIZATION OF HIGH TEMPERATURE DEFORMATION IN NOVEL STRUCTURAL MATERIALS

摘要

The traditional fire resistant reinforced concrete assembly is changing. Sustainability and durabilityrnobjectives are introducing novel structural materials to these assemblies. These novel materials includernnon-conventional reinforcement (glass fiber reinforced polymers – GFRP, high strength steel – HSS, etc.)rnand complex concrete mixtures (concrete with recycled aggregates – RA, etc.). Characterizing the highrntemperature properties of these novel structural components, including their deformation response,rnbecomes essential to explain and model the behavior of contemporary reinforced concrete assemblies underrnfire exposure. The deformation of structural materials at high temperature can be characterized by uniaxialrnmechanical testing using a loading actuator equipped with a controllable heating furnace. Contactrninstruments to measure deformation can be expensive and are easily damaged upon material failure.rnPractice is to remove this instrumentation prior to material failure, at the expense of valuable data. Recentlyrna non-contact optical measurement technique, also known as digital image correlation, has been proposedrnfor high temperature deformation material testing. The technique herein utilizes a loading actuator ontornwhich a furnace with a specimen viewing window is attached. A hi-resolution camera system measuresrndeformation through the viewing window. Herein, this optical measurement technique is used and assessedrnin an attempt to characterize the high temperature deformation behavior of three different novel structuralrnmaterials: concrete with RA, HSS and GFRP. Although RA and HSS could be characterized using thisrnmeasurement technique, difficulty was encountered with GFRP. GFRP underwent partial degradationrnthrough pyrolysis and decomposition of its polymer matrix which affected its surface appearance therebyrncomplicating deformation measurement using optical technology. Critical discussion of the aforementionedrnoptical measurement technique is provided throughout where both advantages and limitations arernconsidered.