Study on the fracture energy and fracture toughness of the polypropylene fiber reinforced concrete

The fracture toughness and the fracture energy are obtained on the notched beams in three-point bending according to the RILEM draft recommendation. An experiment is designed to obtain the law on the alteration of the PPFRC's (Polypropylene Fiber Reinforced Concrete) fatigue life and fatigue strength caused by the fibers. S-IgN curve is plotted according to the experimental data and fatigue is obtained through the Linear Regression. Theoretical analysis of the PPFRC's bending fatigue characteristic is carried out. The fiber's influence on the PPFRC's fatigue behavior is stated and the fiber reinforcement mechanism is discussed. The result shows that the fiber can improve the PPFRC's fatigue life and fatigue strength. The composition and development of the fatigue strain under the cyclic load are analyzed using experimental data. The law of the fatigue damage accumulation and evolution under cyclic load is studied. A fatigue damage mode, which can be used to predict the fatigue life of the PPFRC, is established.