Aligned and random steel fiber reinforced cementitious composites (ASFRC, SFRC) are prepared to study how fiber orientation and volume fraction affect the fatigue life and fracture behaviors of composites. The experimental results indicate the fatigue life of ASFRC exceeds that of SFRC by more than 8 times. Compared with SFRC, the critical effective crack length of ASFRC is improved by more than 17%, which can withstand greater deformation and crack propagation. And the improvement increases with enlarging fiber volume fraction (V_f). Furthermore, based on the experimental results, a two-parameters fracture model considering V_f is developed to predict the fatigue life.

制备排列和随机钢纤维增强水泥基复合材料 (ASFRC、SFRC) 以研究纤维取向和体积分数如何影响复合材料的疲劳寿命和断裂行为。实验结果表明，ASFRC 的疲劳寿命超过 SFRC 的 8 倍以上。与SFRC相比，ASFRC的临界有效裂纹长度提高了17%以上，可以承受更大的变形和裂纹扩展。并且随着纤维体积分数 ( V _f ) 的增大而提高。此外，基于实验结果，开发了一个考虑V _f的双参数断裂模型来预测疲劳寿命。