Assessing the flexural fatigue life of engineered cementitious composites exposed to freeze-thaw cycles

• Published in: Journal of Building Engineering 2024-11, Vol.97, p.110847, Article 110847
• Main Authors: Liu, Shuguang, Lu, Zhaoqiang, Yin, Liqiang, Yan, Changwang, Hou, Huifang, Ba, Yincang, Yin, Dandan, Liu, Shihui, Li, Lin
• Format: Article
• Language: English
• Subjects: Engineered cementitious composites; Equivalent damage; Flexural fatigue equation; Flexural fatigue life; Freeze-thaw
• ISSN: 2352-7102; 2352-7102
• DOI: 10.1016/j.jobe.2024.110847

In cold regions, the infrastructure, particularly roads, bridges, and airport runways, faces prolonged exposure to the coupled effects of freeze-thaw (FT) cycles and fatigue loads. This makes the damage mechanism more complex, seriously affecting the durability of these structures. To investigate the influence of FT damage on flexural fatigue life, this study equated FT damage to the effect of increased stress levels and conducted FT cycles test, nuclear magnetic resonance test, and flexural fatigue test on engineered cementitious composites (ECC). The test results showed that the critical FT cycles number, predicted by using mass loss rate, relative dynamic elastic modulus, and porosity as characteristic parameters, was 507 cycles. The error in representing FT cycles using pore structure characteristic parameters was within 2.0 %. When the stress level S = 0.8, the flexural fatigue life gradually decreased from 22217 cycles to 724 cycles as the number of FT cycles increased. The Weibull distribution was used to obtain flexural fatigue life at different probabilities. Anderson-Darling test verified that the Weibull distribution is a reliable model for predicting material life. By equating FT damage to the effect of increased stress levels, the flexural fatigue equation based on different FT cycles number was established. The study found that the maximum error between the flexural fatigue equation and the Weibull-distributed flexural fatigue life was 18.76 %. Through the application of entropy weight method and grey relational analysis, it was found that the entropy weight grey incidence, euclidean grey correlation, fuzzy affiliation, and fuzzy grey correlation of stress level were 0.799, 0.888, 0.588, and 0.753, respectively. These values indicate that the influence of stress level on flexural fatigue life is greater than that of FT cycle numbers. This research aims to provide new insights for accurately calculating the flexural fatigue life of ECC in cold regions and improving the durability of structures. •The number of FT cycles was identified using mass loss rate, RDEM, and porosity.•The Weibull distribution is a reliable model for predicting the fatigue life.•FT damage is defined as the damage of stress increase on flexural fatigue test.•The impact of stress level outweighs the number of FT cycles on ECC's performance.•The study contributes to improving ECC's durability in cold climates.