**4. Conclusions**

The behaviour of a sustainable concrete containing fly ash and ultra fine fly ash in 3% sulphuric acid and 1.5% nitric acid environment was studied in this research. Based on the results obtained, the following conclusions are made:


**Author Contributions:** Salim Barbhuiya conceived and designed the experiments and wrote the paper. Davin Kumala performed the experiments and analysed the data.

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