Development of greener alkali-activated cement: utilisation of sodium carbonate for activating slag and fly ash mixtures
Development of greener alkali-activated cement: utilisation of sodium carbonate for activating slag and fly ash mixtures
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DOI：
10.1016/j.jclepro.2015.12.010
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发表时间：
2016-02-01
影响因子：
11.1
通讯作者：
Al-Tabbaa, Abir
中科院分区：
文献类型：
--
作者：
Abdalqader, Ahmed F.;Jin, Fei;Al-Tabbaa, Abir
碱激发粉煤灰/矿渣（AAFS）是一种新型的碱激发水泥（AACs），旨在开发一种可持续性更强的替代波特兰水泥（PC）的水泥。在这项研究中，碳酸钠（Na 2CO 3）被用作碱激发粉煤灰（FA）/矿渣混合物。研究了激发剂用量、粉煤灰/矿渣比、养护制度等因素对水泥强度、反应速率、水化产物和微观结构的影响。结果发现，增加Na 2CO 3剂量显着增加抗压强度。夹杂物的高达25重量%的粉煤灰轻微降低了抗压强度高达28天，而夹杂物超过25重量%，可导致显着的强度降低，特别是对于水固化试样。密封养护一般被认为是有益的AAFS浆体的强度发展，特别是在50/50的比例FA/矿渣。结果表明，激发剂用量和粉煤灰/矿渣比对反应速率、反应产物和微观结构均有显著影响。增加活化剂剂量加速反应动力学，而增加FA/矿渣比减慢反应速率。主要的粘结相是C-（N）-A-S-H，其Ca/Si比在0.6和1.0之间变化，主要取决于FA/炉渣比。结果表明，通过合理的粉煤灰/矿渣比、碳酸钠用量和养护制度，可以生产出绿色胶凝材料。(C)2015爱思唯尔有限公司版权所有。
Alkali activated fly ash/slag (AAFS), a newly evolved type of alkali-activated cements (AACs), is here studied with the aim of developing a more sustainable alternative to Portland cement (PC), known for its adverse environmental impact. In this study, sodium carbonate (Na2CO3) was used as the alkali activator for the fly ash (FA)/slag blends. The effects of different factors on the strength, reaction rate, hydration products and microstructure were examined; these factors include the activator dosage, FA/slag ratio, and curing regime. It was found that increasing the Na2CO3 dosage significantly increased the compressive strength. The inclusion of up to 25 wt% fly ash marginally decreased the compressive strength up to 28 days while the inclusion beyond 25 wt% can lead to a remarkable reduction in strength, particularly for water-cured specimens. Sealed curing in general was found to be beneficial to the strength development of AAFS paste especially at a 50/50 ratio of FA/slag. Both the activator dosage and FA/slag ratio were found to have notable influences on reaction rate and reaction products and microstructure. Increasing the activator dosage accelerates the kinetics of the reaction while increasing the FA/slag ratio slows the reaction rates. The main binding phase is C-(N)-A-S-H with varying Ca/Si ratios ranging between 0.6 and 1.0 depending mainly on FA/slag ratio. The results indicated the possibility of production of greener cementing materials by utilizing appropriate ratios of FA/slag, dosage of sodium carbonate, and curing regimes. (C) 2015 Elsevier Ltd. All rights reserved.