Abstract:In order to solve the huge environmental challenge caused by the massive accumulation of solid waste coal gangue, the coal gangue was used as coarse aggregate instead of ordinary crushed stone. Based on this research, the influence of coal gangue content(0, 10%, 20%, 30%)on the compressive strength of concrete was studied.The microscopic pore development law of different content of coal gangue concrete at various ages was tested by the nuclear magnetic resonance technology. At the same time, the relationship between the pore structure parameters of different content of coal gangue and the compressive strength of coal gangue with different content was explored by combining with the gray entropy metho. Combined with grey system theory, GM(1,4)grey prediction model was established. The results show that the addition of coal gangue will reduce the compressive strength of concrete. The area of T2 spectrum map increases with the increase of coal gangue content, and the proportion of small and micro pores increases compared with ordinary concrete. According to the study of grey entropy correlation, the strength of coal gangue concrete and the irreducible fluid saturation, porosity and the proportion of pore diameter in pore structure were 0.1~1.0 μm. The correlation degree of micron pores in the pore structure was the highest, which were 0.999 16, 0.989 44, and 0.995 93, respectively. The average relative error between the test value and the predicted value of the established gray correlation model GM(1,4)was 1.97%, which has good prediction accuracy. This research can provide a reference for the application of coal gangue as coarse aggregate in practical engineering.