**5. Conclusions**

As a result of the research presented in this article, the following research objectives have been met:


It was shown that the developed general model of carbonation for concrete with a wide range of water/cement and ash to cement ratios and a constant set of components as well as fixed technological procedures could be a useful tool for the experimental design of optimal cover thickness.

**Author Contributions:** Conceptualization, P.W. (Piotr Woyciechowski); Methodology, P.W. (Paweł Woli ´nski); Formal Analysis, P.W. (Piotr Woyciechowski) and G.A.; Investigation, P.W. (Paweł Woli ´nski); Writing—Original Draft Preparation, P.W. (Piotr Woyciechowski); Writing—Review and Editing, P.W. (Piotr Woyciechowski); Visualization, G.A. and P.W. (Paweł Woli ´nski)

**Funding:** This research was funded by the Department of Building Materials Engineering of the Faculty of Civil Engineering at Warsaw University of Technology.

**Conflicts of Interest:** The authors declare no conflict of interest.

### **References**


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