Compressive Strength and Durability of Coal Gangue Aggregate Concrete
MA Hongqiang1, YI Cheng1, ZHU Hongguang1, DONG Zuochao2, CHEN Hongyu1, WANG Jiaxin1, LI Deyi1
1 School of Mechanics and Civil Engineering, China University of Mining and Technology Beijing, Beijing 100083; 2 School of Architecture and Civil Engineering, Jiangsu University of Science and Technology, Zhenjiang 212005
Abstract: We herein prepared a series of concrete specimens with the mixed coarse aggregate of coal gangue and ordinary gravel, in which the calcined or uncalcined coarse coal gangue equivalently substituted for 0%,30%,50%,70% and 100% of the gravel. The influences of substitution amount and 700 ℃ calcination of coarse coal gangue on compressive strength, anti-carbonation performance, rapid chloride ion penetration and sulfate attack resistance of the concrete were investigated, and the mineral composition changes and the microstructure were observed by XRD and SEM, respectively. Our experiment validated the feasibility of utilizing coal gangue as coarse aggregate for concrete, with a maximum substitution amount determined by the concrete’s designed strength and environmental factors. The existence of the cavities at the bond between the coal gangue and the cementing material inhibits compressive strength and durability of the concrete, but is beneficial to the concrete’s resistance against chloride ion per-meation. The substitution of calcined coarse coal gangue can result in a more dense concrete structure compared to uncalcined coarse coal gangue, and nonetheless holds slight advantage due to its intrinsic defects. Further research is expected to promote the excitation upon the calcined coarse coal gangue aggregate and amplify its advantage. The present work can provide experimental basis and theoretical reference for the highly efficient utilization of coal gangue.
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