养护条件对粉煤灰地聚物混凝土早期收缩性能的影响  

Influence of curing conditions on early shrinkage of fly ash geopolymer concrete

作　　者：毛明杰[1] 韦旭朋 韩鹏飞 周世腾 MAO Mingjie;WEI Xupeng;HAN Pengfei;ZHOU Shiteng(School of Civil and Hydraulic Engineering,Ningxia University,Yinchuan 750021,China)

机构地区：[1]宁夏大学土木与水利工程学院,宁夏银川750021

出　　处：《混凝土》2019年第3期90-93,共4页Concrete

基　　金：国家自然科学基金(51568055)

摘　　要：为推进粉煤灰地聚物混凝土的应用,通过与粉煤灰混凝土对比,探究了粉煤灰地聚物混凝土包裹养护条件下早期抗压强度和不同养护条件下收缩性能的发展情况。结果表明:相较于粉煤灰混凝土,粉煤灰地聚物混凝土包裹养护条件下28 d微观结构密实,且抗压强度增长速率在7～28 d较为显著。干燥养护条件下粉煤灰地聚物混凝土早龄期1 d收缩率较大,此后随着龄期的增长收缩幅度先增大后减小,90 d收缩率大于粉煤灰混凝土;包裹养护下90 d收缩率均小于干燥养护,归因于塑料薄膜隔绝了试件内部水分的蒸发;水中养护14 d龄期前均发生有害膨胀,之后呈现不同程度的收缩,90 d粉煤灰地聚物混凝土收缩率略低于粉煤灰混凝土。此外,进一步拟合出干燥和包裹养护条件下两种混凝土的经时收缩关系式,以期为工程构件的早期裂缝预防提供理论依据。In order to promote the application of fly ash geopolymer concrete,and compared with fly ash concrete,the development of early compressive strength and shrinkage performance under different curing conditions of fly ash geopolymer concrete was explored.The results show that the microstructure of fly ash concrete is dense compared with fly ash concrete after 28 days,so the growth rate of compressive strength is more obvious in 7~28 days.The shrinkage of fly ash concrete during early age 1 day under drying curing is larger,then with the increase of age,the rate of shrinkage increases firstly and decreases then,the shrinkage of 90 days is greater than fly ash concrete.The every shrinkage of 90 days under packaging curing are less than drying curing mainly because the plastic film stops the water within specimen lossing.It also presents that two kinds of concretes before 14 days under water curing both have an expansion hazard and then they present different degrees of shrinkage,this contributes to the data that fly ash geopolymer concrete is slightly lower when compared to the shrinkage of 90 days fly ash concrete.In addition,the time-dependent shrinkage relationship of fly ash geopolymer concrete under drying and packaging curing is further fitted to provide a theoretical basis for early crack prevention of engineering components.

关 键 词：粉煤灰地聚物混凝土 抗压强度 微观结构 收缩率 经时收缩关系式 

分 类 号：TU528.064[建筑科学—建筑技术科学]