Abstract: In order to improve the utilization rate of coal gangue and improve the overall performance of coal gangue masonry
mortar,the effects of basalt fiber length,content and fly ash substitution rate on the consistency and mechanical properties
of coal gangue masonry mortar were studied by response surface method. Furthermore,the multi-objective optimization of coal
gangue-basalt fiber masonry mortar is carried out by combining NSGA-Ⅱ algorithm and entropy weight TOPSIS comprehensive
evaluation method. The results show that the appropriate amount of basalt fiber can improve the mechanical properties of coal
gangue mortar,but the addition will reduce the consistency of mortar. Appropriate amount of fly ash can improve the consistency
and mechanical properties of mortar. SEM analysis shows that the hydration products of coal gangue-basalt fiber mortar are
mainly Ca(OH)₂,Aft and C-S-H gel. Appropriate amount of basalt fiber can improve the internal structure of coal gangue
mortar and reduce pores and cracks. After multi-objective optimization,the best parameter scheme is obtained:the fiber length
is 9 mm,the fiber volume content is 0. 13%,and the fly ash replacement rate is 5. 1%. This study can provide theoretical support
and technical reference for the parameter optimization design of coal gangue-basalt fiber masonry mortar.