摘要
低钙粉煤灰在常温条件下合成地聚物存在反应度低、强度低的问题。本研究在低钙粉煤灰中掺入20%赤泥制备地聚物,研究其力学性质,并通过SEM、EDS和FT-IR分析地聚物的微观结构变化。进一步研究了化学配比n(Si)/n(Al)=1.8～2.5、n(Na)/n(Al)=0.8～1.1以及在100%相对湿度养护0～7 d对赤泥-粉煤灰基地聚物性质的影响。试验发现常温养护的赤泥-粉煤灰基地聚物的力学性质明显优于低钙粉煤灰基地聚物,且n(Si)/n(Al)=2.0～2.2、n(Na)/n(Al)=1.0为前者制备的最优配比,而较高的养护湿度可提高其早期强度。这证明赤泥对常温合成粉煤灰基地聚物有促进作用,并揭示了赤泥-粉煤灰基地聚物比粉煤灰基地聚物更密实的微观结构、更多的地聚物胶凝体形成和更高的反应度是前者力学性质优于后者的主要原因。
Class F fly ash has the low reaction degree and low strength problems in geopolymer synthesis at ambient temperature.In this study,20%red mud was added to Class F fly ash to synthesize geopolymer,of which the mechanical properties were investigated.In addition,microstructural change of the geopolymer was explored with SEM,EDS and FT-IR.Furthermore,the effect of n(Si)/n(Al)=1.8-2.5 and n(Na)/n(Al)=0.8-1.1,and curing period at 100%relative humidity for 0-7 days on the red mud-fly ash based geopolymer was investigated.It found that the mechanical properties of the ambient temperature cured red mud-fly ash based geopolymer were significantly improved compared to the Class F fly ash based geopolymer.In addition,n(Si)/n(Al)=2.0-2.2 and n(Na)/n(Al)l=1.0 were the optimum chemical composition for the synthesis of red mud-fly ash based geopolymer,and higher curing humidity was beneficial for its early strength.The improving effect of red mud on the ambient condition cured fly ash based geopolymer was found.It also revealed that the more compact microstructure,the more geopolymer gels formed and higher reaction degree of red mud-fly ash based geopolymer than fly ash based geopolymer were the main reasons for the better mechanical properties of the former one.
作者
张默
王诗彧
ZHANG Mo;WANG Shiyu(School of Civil and Safety Engineering,Dalian Jiaotong University,Dalian 116028)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2019年第6期980-985,共6页
Materials Reports
基金
辽宁省自然科学基金计划重点项目(20170520406)
中国博士后科学基金面上资助(2017M621125)~~
关键词
赤泥-粉煤灰基地质聚合物
养护条件
化学配比
力学性质
微观结构
red mud-fly ash based geopolymer
curing condition
chemical composition
mechanical properties
microstructure
