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The objective of this work is two-fold. First, we attempt to fit the experimental data on the flexural fatigue of plain and fiber-reinforced concrete with a probabilistic model (Saucedo, Yu, Medeiros, Zhang and Ruiz, Int. J. Fatigue, 2013, 48, 308–318). This model was validated for compressive fatigue at various loading frequencies, but not for flexural fatigue. Since the model is probabilistic, it is not necessarily related to the specific mechanism of fatigue damage, but rather generically explains the fatigue distribution in concrete (plain or reinforced with fibers) for damage under compression, tension or flexion. In this work, more than 100 series of flexural fatigue tests in the literature are fit with excellent results. Since the distribution of monotonic tests was not available in the majority of cases, a two-step procedure is established to estimate the model parameters based solely on fatigue tests. The coefficient of regression was more than 0.90 except for particular cases where not all tests were strictly performed under the same loading conditions, which confirms the applicability of the model to flexural fatigue data analysis. Moreover, the model parameters are closely related to fatigue performance, which demonstrates the predictive capacity of the model. For instance, the scale parameter is related to flexural strength, which improves with the addition of fibers. Similarly, fiber increases the scattering of fatigue life, which is reflected by the decreasing shape parameter.

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The utilization of structural high-performance concrete reinforced with polypropylene fibers in applications demanding long exposure times to high temperatures, such as in case of thermal energy storage systems, is analyzed in this work. Different temperatures: 100, 300, 500 and 700°C (hot), as well as cooled-down states (cold) and different exposure times (6, 24 and 48 h) have been analyzed. The thermogravimetric analysis, fracture behavior, compressive strength, the Young's modulus and tensile strength of concrete were also experimentally determined and subsequently, a comprehensive analysis of the thermal and mechanical behavior of highperformance concrete under different thermal conditions has been carried out, broadening with longer exposure times the available results about the behavior of high-performance fiber reinforced concrete subjected to high-temperatures. When the temperature is increased, the mechanical properties of this concrete diminishes. The results shown that once thermal and moisture equilibriums are reached there is no influence of the exposure time. They provide useful information about the influence of different parameters of fiber-reinforced concrete subjected to high temperatures.