Effect of combined activator of Ca(OH)2 and Na2CO3 on workability and compressive strength of alkali-activated ferronickel slag system
Effect of combined activator of Ca(OH)2 and Na2CO3 on workability and compressive strength of alkali-activated ferronickel slag system
复制标题
Ca(OH)2和Na2CO3复合活化剂对碱活化镍铁渣体系和易性及抗压强度的影响
DOI：
10.1016/j.cemconcomp.2021.104179
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发表时间：
2021-07-22
影响因子：
10.5
通讯作者：
Ji, Tao
中科院分区：
文献类型：
--
作者：
Bian, Zuwang;Jin, Guowang;Ji, Tao
将镍铁渣应用于碱激发体系，有望减轻环境污染。由于反应速度较慢，强度较好，采用Ca(OH)2和Na2CO3(摩尔比为1：1)的复合激发剂，研究了复合激发剂含量(即3、5、7和9%Na2O当量)对碱激发镍渣系统的工作性、标准稠度用水量、凝结时间、安定性和抗压强度的影响。用X射线衍射仪、热重分析、扫描电子显微镜和压汞测孔仪对反应产物和孔结构进行了表征。结果表明，随着Na2O当量的增加，AFS系统的工作性降低，抗压强度先增加后降低。Na2O当量从3%增加到7%，加速了反应过程，促进了C-(A)-S-H凝胶、方解石和水滑石的形成，从而提高了抗压强度。当Na2O当量为9%时，由于微裂纹导致的孔隙率增加，导致抗压强度降低。综合考虑工作性和抗压强度，AFS体系的最佳Na2O当量为5%。
The utilization of ferronickel slag into the alkali-activated system is promising to mitigate environmental pollution. Due to slower reaction rate and satisfactory strength, a combined activator of Ca(OH)2 and Na2CO3 (molar ratio of 1: 1) was used to investigate the effect of combined activator content (i.e. 3, 5, 7 and 9% Na2O equivalent) on the workability, water requirement of normal consistency, setting time, soundness and compressive strength of alkali-activated ferronickel slag (AFS) system. X-ray diffraction, thermogravimetric analysis, scanning electron microscopy and mercury intrusion porosimetry were used to characterize the reaction products and pore structure. Results indicate that the workability of AFS system decreases with the increase of Na2O equivalent, while the compressive strength first increases and then decreases. The reaction process is accelerated with Na2O equivalent from 3% to 7%, thereby promoting the formation of C-(A)-S-H gel, calcite and hydrotalcite that can improve the compressive strength. Whereas an increasing porosity due to microcracks is observed at 9% Na2O equivalent, thus resulting in the decrease of compressive strength. Considering the workability and compressive strength, the optimal Na2O equivalent in AFS system is 5%.