INFLUENCE OF SUB-ZERO TEMPERATURE ON FRACTURE PROPERTIES OF PLAIN AND SYNTHETIC FIBER REINFORCED CONCRETES

摘要

Fracture toughness of synthetic fiber-reinforced concrete composites was investigated at normal and low (-39℃) temperature. Three types of synthetic fibers were chosen for this purpose: fibrillated polypropylene fiber, monofilament polypropylene fiber, and nylon monofilament fiber. Fracture tests were performed on contoured double cantilever beam specimens and the fracture resistance was experimentally modeled by an R-curve behavior. The effect of fiber type and fiber volume on the R-curve was investigated. A more pronounced R-curve behavior was seen to occur at low temperature, i.e, composites appeared tougher at sub-zero temperature. Also, at low temperature, fracture toughness of composites increased with an increase in fiber volume, which is similar to the behavior typically observed at normal temperature.