Abstract: In order to explore the corrosion and deterioration law of basalt fiber concrete under the coupling effect of compound salt solution and dry-wet cycle, the macro-microscopic corrosion degradation tests of basalt fiber concrete specimens with different volume contents (0%, 0.1%, 0.2%, 0.3%) were carried out, under the combined action of composite salt solution (NaCl+MgSO₄+Na₂SO₄) with different concentrations (clean water, reference concentration, 5 times reference concentration, 10 times reference concentration) and dry-wet cycles. The results show that the addition of basalt fiber improves the salt corrosion resistance of concrete, and when the content of basalt fiber is 0.3%, the relative dynamic elastic modulus of the specimen has the smallest fluctuation and the most stable performance. Concrete corrosion products are mainly ettringite (AFt) and gypsum under the action of combined salt solution corrosion. The corrosion products increase continuously with the increase of the number of drying and wetting cycles, and the specimen is finally destroyed by the combined action of physical and chemical corrosion. According to the microstructure and composition analysis of corrosion products in different corrosion ages, it is found that adding basalt fiber reduces the consumption rate of Ca(OH)₂ in concrete, and the content of corrosion products decreases correspondingly, and the ability of concrete to resist compound salt erosion is enhanced. The results can provide scientific basis for the engineering application of basalt fiber concrete in the saline soil area of Southern Xinjiang.

Key words: basalt fiber concrete, compound salt erosion, drying and wetting cycle, macro-performance, microstructure, composites