To enhance the resource utilization of raw coal gangue,this study partially or fully replaced raw coal gangue with natural aggregates to prepare concrete.The effects of factors such as water-cement ratios,replacement rates,the addition of silica fume and mixing methods on the compressive strength,splitting strength,stress-strain relationship curve,elastic modulus,peak load and peak strain of specimens were analyzed.Additionally,the microstructure charac-teristics of the specimens'failure surfaces were observed using scanning electron microscopy.The results show that the mechanical properties of raw coal gangue concrete were improved by using a secondary mixing process,and the combination of the secondary mixing process with the addition of silica fume.The former method exhibited greater improvement than the latter.An increase in replacement rate and water-cement ratio is detrimental to the mechanical performance of non-self-igniting coal gangue concrete specimens,with the latter experiencing a greater reduction in magnitude.Furthermore,scanning electron microscopy observations reveal that the interfacial transition zones of the specimens using the secondary mixing process exhibited fewer pores and a denser structure,which effectively im-proved the macroscopic mechanical properties of the specimens.
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