摘要
由于粉煤灰的非均质性,很难直接预测粉煤灰的活性。本实验研究了不同粉煤灰在不同时间、温度和碱浓度条件下的浸出过程(先将粉煤灰在碱液中溶解,再将其残留物在酸溶液中解离)。通过电感耦合等离子体发射光谱仪(ICP)和化学分析表明,温度、反应时间和碱浓度都会影响粉煤灰的溶解速率和浸出含量。粉煤灰中浸出的反应性n(Si)/n(Al)为2.3~2.7,粉煤灰中硅和铝的总浸出量与成型用其制备的地聚合物强度呈正相关。另外,可发现建立在硅酸盐水泥体系上的粉煤灰活性评价体系并不完全适用于地聚合物体系。通过XRD、FTIR和SEM分析可发现,粉煤灰由反应性材料和惰性材料组成,而活性物质在地聚合过程中迅速溶解,酸完全解离在地聚合过程中生成的凝胶,浸出过程更能准确表征粉煤灰中反应性物质的含量。碱溶解-酸解离法可定量估算粉煤灰的反应物含量和反应性n(Si)/n(Al),并简单预测用于地聚合物体系的粉煤灰的潜在反应活性,还可指导粉煤灰地聚合物的配比设计。
Due to the heterogeneity of fly ash,it is difficult to anticipate the potential reactivity of fly ash.The leaching process of different fly ash under different conditions of time,temperature and alkali concentration(fly ash is first dissolved in lye,and its residue is dissociated in acid solution).Inductively Coupled Plasma Optical Emission Spectrometer(ICP-OES)and chemical analysis results show that temperature,reaction time and alkali concentration all affect the dissolution rate and leaching content of fly ash.The leaching reactive n(Si)/n(Al)of fly ash was 2.3-2.7,and the total leaching amount of silica and aluminum from fly ash was positively correlated with the strength of geopolymers.It is found that the grading of fly ash used in cement system is not completely applicable to geopolymer system.XRD,FTIR and SEM analysis results show that fly ash is composed of reactive parts and inert parts.The active substances dissolve rapidly in the alkali dissolution process,the acid completely dissociates the gel formed during the geo-polymerization process,and the leaching process can more accurately characterize the content of reactive substances in fly ash.Therefore,alkali-acid combined determination method can be used to quantitatively estimate the reactant content and reactive n(Si)/n(Al)of fly ash,to simply and rapidly predict the potential reactivity of fly ash used in geopolymer systems,and to design the fly ash-based geopolymer.
作者
刘鑫
田轶轩
黄金凤
万城铭
杨宏宇
万朝均
LIU Xin;TIAN Yixuan;HUANG Jinfeng;WAN Chengming;YANG Hongyu;WAN Chaojun(College of Materials Science and Engineering,Chongqing University,Chongqing 400044,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2022年第2期98-104,共7页
Materials Reports
基金
绿色建筑材料国家重点实验室开放基金资助(0211002402028)
重庆市研究生科研创新项目(CYS18003)。
关键词
粉煤灰
地聚合物
活性
溶解
抗压强度
fly ash
geopolymer
activity
dissociation
compressive strength
