Research on the flexural performance of reinforced engineered cementitious composite beams

摘要

The bending performance of polypropylene fiber reinforced engineered cementitious composite (PP-ECC) beams was studied. A total of five reinforced concrete (RC) beams were prepared and tested. The test variables include matrix type, longitudinal reinforcement diameter, and longitudinal reinforcement ratio. The study found that ECC is an ideal building material to improve the bending performance of RC beams. For the failure mode, even if the ultimate load is reached, no local cracks are observed in the ECC beam. On the contrary, due to the high ductility of the ECC material, multiple microcracks appear in the tension zone of the beam. From the perspective of bending performance, the use of ECC materials as the matrix of RC beams can not only increase the cracking load, yield load, and ultimate load of RC beams but also increase its ductility and energy absorption capacity. A method for predicting the flexural bearing capacity of ECC beams considering the effect of fiber tensile stress is proposed. The experimental data in this study are compared with the experimental data in the previous literature, and the prediction results of this model and other previous models are obtained. The average ratio of the predicted value of the flexural bearing capacity of the RC beam to the experimental value is 0.979, and the coefficient of variation is 0.016.