摘要
地聚物早期强度高、耐高温性能好以及对环境污染少,是国内外研究非常活跃的一种新型无机胶凝材料,掌握地聚物的收缩和徐变特性对确定其能否替代硅酸盐水泥的地位十分重要。文中回顾了近几年来地聚物在收缩和徐变两方面的研究成果,重点梳理了粉煤灰地聚物(AAFA)和矿渣地聚物(AAS)的收缩和徐变特性、机理及改善措施。结果表明:AAFA在室温下的干缩率较大,高温固化的AAFA可以获得比普通硅酸盐水泥基材料(OPC)更小的干缩率;AAS的干缩率比OPC的大得多;地聚物的收缩机理与普通硅酸盐水泥的不完全相同;适当提高固化温度、降低钠含量和掺入纤维等可以在一定程度上减轻地聚物的收缩;粉煤灰和适量的矿渣制备的地聚物混凝土既可满足强度的要求又可以获得比OPC混凝土更小的干缩率,是一种前景广阔的建筑材料;AAFA混凝土的徐变较OPC混凝土小,但AAS混凝土的徐变较OPC混凝土大,在AAFA中加入少量矿渣对其徐变的影响也不大;利用纳米压痕技术可以快速、可靠地评价地聚物的徐变。文中还对今后需进一步研究的相关问题提出了建议。
Geopolymer,with merits of high early strength,good thermostable performance and less environmental pollution,is a new inorganic cementing material involving intensive research both at home and abroad.It is very important to grasp the shrinkage and creep characteristics of geopolymer to determine whether it can be used to replace Portland Cement(OPC)or not.The research of geopolymer on shrinkage and creep in recent years were reviewed in this paper focusing on the shrinkage and creep characteristics,mechanism and improvement measures of fly ash based geopolymer(AAFA)and slag based geopolymer(AAS).The results show that:AAFA has a larger shrinkage rate at room temperature,and AAFA cured at high temperature can obtain a smaller shrinkage rate than OPC;AAS shrinkage rate is much larger than OPC;the shrinkage mechanism of geopolymer is not exactly the same as that of OPC;the shrinkage of geopolymer can be reduced to a certain extent through properly raising the curing temperature,reducing the sodium content and adding fibers;the geopolymer concrete prepared with fly ash and appropriate amount of slag is a promising building material that can meet the requirements of strength and obtain a smaller dry shrinkage than OPC concrete;AAFA concrete has a smaller creep than OPC concrete,but AAS concrete has a larger creep than OPC concrete.In addition,the addition of a small amount of slag to AAFA has little effect on creep.The nano-indentation technology can be used to quickly and reliably evaluate the creep of geopolymer concrete.Finally,some suggestions for further research were put forward.
作者
杨世玉
赵人达
曾宪帅
靳贺松
李福海
YANG Shiyu;ZHAO Renda;ZENG Xianshuai;JIN Hesong;LI Fuhai(School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, Sichuan,China)
出处
《华南理工大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2020年第12期91-104,共14页
Journal of South China University of Technology(Natural Science Edition)
基金
国家自然科学基金资助项目(51778531)
四川省科技计划项目(2019YFG0001)。
关键词
地聚物
混凝土
收缩
徐变
geopolymer
concrete
shrinkage
creep
