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AN EXPERIMENTAL STUDY ON BENDING FATIGUE PROPERTEIS OF CONCRETE USING ORGANIC SHORT FIBER

： In this study, the bending fatigue of concrete mixed with vinylon or polypropylene fiber was studied for the purpose of application to precast concrete. Experimental factors in the bending fatigue test were the presence or absence of the fiber, fiber types, aspect ratios, and maximum stress ratios during loading. As a result of this research, the following was found：1） The number of fractures due to bending fatigue was 9.9 to 1336 times larger than of the standard concrete by incorporating organic short fibers. 2） In comparison with organic short fibers having similar aspect ratios, the difference from the polypropylene fiber was not recognized when the stress ratio was small, while, when it was large, the fatigue life of the vinylon fiber was good. 3） As a result of observing the cross section where the fatigue fracture occurred, the ratio of broken fibers increased as the stress ratio became smaller.