Carbonation resistance of fly ash concrete (FAC) and recycled aggregate concrete (RAC) has been extensively tested in the past decade, but there are still no recommendations for their application in codes of practice. Therefore, the main objective of this study was to determine the minimum concrete cover depth of RAC and FAC exposed to carbonation to satisfy the required service life. In this study, the relationship between concrete compressive strength at 28 days (f_cm) and inverse effective carbonation resistance (R⁻¹_ACC) was established. The analysis was carried out on all data available in the literature in order to establish this relationship for FAC and RAC made with different replacement percentages. After establishing a relationship between R⁻¹_ACC and f_cm, a prediction of the service life was made using the fib‐Bulletin 34 (2006, Model code for service life design (1st ed.). Lausanne: International Federation for Structural Concrete (fib)) prediction model for all exposure classes to carbonation. For same concrete class, it can be concluded that in the case of RAC there was no significant difference in the duration of the service life compared with natural aggregate concrete, even at 100% replacement of natural aggregate with recycled ones. For concrete up to 35% of fly ash in total cementitious materials, concrete cover for satisfying the required service life of 50 years was 40% higher compared with Portland cement concrete, and more than two times higher in case of concrete with 40–70% fly ash.

中文翻译：

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碳化碳化绿色混凝土混凝土覆盖层厚度的评估

在过去的十年中，粉煤灰混凝土（FAC）和再生骨料混凝土（RAC）的抗碳化性得到了广泛的测试，但是在实践准则中仍然没有建议使用它们。因此，本研究的主要目的是确定暴露于碳酸中的RAC和FAC的最小混凝土覆盖深度，以满足所需的使用寿命。在这项研究中，混凝土在28天抗压强度（f _cm）与有效抗碳化强度的反比（R ^-1 _{ACC）之间的关系}） 建立了。对文献中可用的所有数据进行了分析，以建立具有不同替代百分比的FAC和RAC的这种关系。建立R ^-1 _ACC与f _cm之间的关系后，使用fib － Bulletin 34（2006年，使用寿命设计模型代码（第一版））对使用寿命进行了预测。纤维））碳酸化的所有暴露类别的预测模型。对于相同的混凝土类别，可以得出结论，就RAC而言，即使将天然骨料用再生骨料替代100％，与天然骨料混凝土相比，使用寿命也没有显着差异。对于全部胶凝材料中粉煤灰不超过35％的混凝土，满足50年要求使用寿命的混凝土覆盖层比硅酸盐水泥混凝土高40％，而对于40-70％的混凝土，其覆盖率要高两倍以上粉煤灰。