The objective of this paper is to analyse the mechanical behaviour of polypropylene fibre reinforced concrete subjected to load cycles and propose a model to predict the crack-opening increase and mechanical performance evolution over the cycles. Fatigue tests were performed in pre-cracked specimens with two fibre types and contents to assess the evolution of the crack-opening for prescribed numbers of load cycles. The residual flexural tensile strength was assessed before and after these tests to estimate the impact of the cycles in the remaining resistant capacity of the specimens. Results suggest that the mechanism of crack propagation is independent of the fibre type and content. The accumulated damage due to the cycles produces an offset in the quasi-static residual tensile strength curve. These findings underpin the proposal of a model to predict the evolution of the crack-opening and the remaining resistant capacity. An optimisation procedure is proposed to derive the model parameters using a limited number of initial load cycles.

本文的目的是分析聚丙烯纤维增强混凝土在荷载作用下的力学行为，并提出一个模型来预测随着周期的开裂增加和力学性能的演变。在具有两种纤维类型和含量的预开裂试样中进行了疲劳测试，以评估规定次数的载荷循环下开裂的演变。在这些测试之前和之后，评估残余挠曲拉伸强度，以评估循环对样品剩余抗力的影响。结果表明，裂纹扩展的机理与纤维类型和含量无关。由于循环而造成的累积损伤会在准静态残余拉伸强度曲线中产生偏移。这些发现为预测裂纹扩展和剩余抗力能力的模型提出了建议。提出了一种优化程序，以使用有限数量的初始载荷循环来导出模型参数。