Ma Hongqiang, Zhu Hongguang, Yi Cheng, Fan Jingchong, Chen Hongyu, Xu Xiaonan, Wang Tao
School of Mechanics and Civil Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China.
Materials (Basel). 2019 Jul 12;12(14):2250. doi: 10.3390/ma12142250.
In this paper, slag is used as a calcium source to make alkali-activated coal gangue-slag (AACGS) based material. The reaction mechanism of AACGS materials was discussed in depth by means of XRD, FT-IR, Si MAS-NMR (nuclear magnetic resonance) and SEM-EDS (energy dispersive spectrometer). The experimental results show that coal gangue can be used as a raw material for preparing alkali-activated materials. The liquid-solid ratio is the most influential factor on AACGS paste fluidity and strength, followed by slag content. As the modulus of sodium hydroxide increases, the depolymerization process of the reactant precursor is accelerated, but the high sodium hydroxide concentration inhibits the occurrence of the early coal gangue-slag polycondensation reaction, and exerts little effect on the 28 d compressive strength. Ca in the slag promotes exchange with Na, and the product is converted from N-A-S-H gel to C-(A)-S-H gel, and C-(A)-S-H is formed with higher Ca/Si ratio with the increase of slag content. The slight replacement of coal gangue by slag can greatly improve the reaction process and the strength of AACGS materials.
在本文中，矿渣被用作钙源来制备碱激发煤矸石-矿渣（AACGS）基材料。通过XRD、FT-IR、Si MAS-NMR（核磁共振）和SEM-EDS（能量色散谱仪）等手段深入探讨了AACGS材料的反应机理。实验结果表明，煤矸石可作为制备碱激发材料的原料。液固比对AACGS浆体流动性和强度的影响最大，其次是矿渣含量。随着氢氧化钠模量的增加，反应物前驱体的解聚过程加快，但高浓度氢氧化钠会抑制煤矸石-矿渣早期缩聚反应的发生，对28 d抗压强度影响较小。矿渣中的Ca促进与Na的交换，产物从N-A-S-H凝胶转变为C-(A)-S-H凝胶，且随着矿渣含量的增加，形成的C-(A)-S-H具有更高的Ca/Si比。用矿渣轻微替代煤矸石可大大改善AACGS材料的反应过程和强度。
