摘要
研究了养护温度对MgO微膨胀混凝土变形性能的影响,利用XRD、DSC-TG和SEM分析了MgO在水泥浆体中的水化机理和膨胀特性。结果表明:养护温度对外掺MgO砂浆的自由膨胀率影响显著,养护温度越高,早期膨胀越大,膨胀曲线也越早达到稳定。养护温度的升高加快了MgO的水化速率、加速Mg(OH)_2晶体的形成和增大,这是由于温度的升高加速了MgO水化后Mg^(2+)和OH^-的迁移速率,使得Mg(OH)_2晶体的形成速度也相应加快,膨胀效应提前。随着养护温度的升高,Mg(OH)_2微观结构也发生了一定的变化,由短片状的晶体变成纤维状,并伴有微裂纹生成。
The influence of curing temperature on the deformation properties of MgO micro-expansive concrete were studied.Hydration mechanism and expansion characteristics of MgO in cement paste were analyzed by XRD、DSC-TG and SEM.Results indicated curing temperature had a great effect on free expansion ratio of MgO mortar,the higher the curing temperature,the bigger the early expansion,the sooner the inflation curves stabilized.Curing temperature accelerated the hydration rate of MgO and the formation of Mg(OH)2 crystals and increasment,because the increased temperature accelerated migration rate of Mg^2+ and OH^- after the MgO hydrating,then made the formation of Mg(OH)2 crystal to be accelerated accordingly and expansion effect in advance.With the increase of curing temperature,there were some changes in microstructure of Mg(OH)2,the short lamellar crystals turned fibrous which accompanied micro cracks.
作者
张建峰
董芸
陈霞
杨华全
ZHANG Jianfeng;DONG Yun;CHEN Xia;YANG Huaquan(Changjiang River Scientific Research Institute,Wuhan 430010,China;National Dam Safety Engineering Technology Research Center,Wuhan 430010,China)
出处
《混凝土》
CAS
北大核心
2019年第3期49-52,共4页
Concrete
基金
国家重点研发计划子课题:水电工程用微膨胀高抗裂低热硅酸盐水泥基材料的研究与应用(2016YFB0303601)
关键词
养护温度
MGO
自由膨胀率
水化速率
迁移速度
curing temperature
MgO
free expansion rate
hydration rate
migration rat
