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温度匹配条件下低活性氧化镁对混凝土性能的影响研究
作者：程福星1，胡敏2，张珍杰1，周月霞1，向飞2，王海龙2
（1.武汉源锦建材科技有限公司，湖北 武汉 430083；2.武汉三源特种建材有限责任公司，湖北 武汉 430083）
摘要：研究了不同低活性氧化镁在温度匹配条件下对混凝土力学性能、体积变形和弹性模量的影响。结果表明：相较于空白组，MgO-2s和MgO-4s可提高混凝土早期抗压强度，但后期抗压强度比均低于100%；掺MgO-2s、MgO-4s和MgO-6s，混凝土试件3 d和7 d抗折强度分别提高4.5%、7.6%、1.5%和4.4%、7.3%、8.8%，随着养护龄期的延长，抗折强度比逐渐减小；温度对低活性氧化镁膨胀能释放极其敏感，在自由膨胀下，掺不同活性氧化镁混凝土始终表现出微膨胀状态，在限制膨胀下，掺MgO-6s混凝土随着龄期的延长，逐步表现出收缩状态，但两者趋势及发展规律接近，对于补偿收缩作用效果，掺MgO-2s最优，掺MgO-4s次之，掺MgO-6s稍差；混凝土弹性模量的产生主要发生在早期，后期变化不大，掺低活性氧化镁可提高混凝土早期的弹性模量，后期有一定下降。
关键词：混凝土；温度匹配；低活性；氧化镁；应变；弹性模量
中图分类号：TU528.042+.4 文献标识码：A 文章编号：1001-702X（2022）12-0031-05
Influence of low-activity magnesium oxide on concrete properties under temperature matching conditions
CHENG Fuxing1，HU Min2，ZHANG Zhenjie1，ZHOU Yuexia1，XIANG Fei2，WANG Hailong2
（1.Wuhan Ujoin Building Material Technology Co. Ltd.，Wuhan 430083，China；
2.Wuhan Sanyuan Special Building Material Co. Ltd.，Wuhan 430083，China）
Abstract：The effects of different low-activity magnesium oxide on the mechanical properties，volume deformation and elastic modulus of concrete under temperature matching conditions were studied. The results show that compared with the blank group，MgO-2s and MgO-4s can improve the early compressive strength of concrete，but the ratio of late compressive strength is lower than 100%；the 3 d and 7 d flexural strengths of the specimens increased by 4.5%，7.6%，1.5% and 4.4%，7.3% and 8.8%，respectively. With the extension of the curing age，the flexural strength ratio will gradually decrease；temperature is extremely sensitive to expansion energy release of low active magnesium oxide. Under the free expansion，the concrete mixed with different activated magnesia always shows a slight expansion state，under the limited expansion，the MgO-6s concrete gradually shows a shrinkage state with the extension of age，but the two trend and development law are close. In terms of the effect of compensating shrinkage，MgO-2s is better than MgO-4s and is better than MgO-6s；the elastic modulus of concrete mainly occurs in the early stage，and changes little in the later stage，it can improve the elastic modulus of concrete in the early stage，and it will decrease to a certain extent in the later stage.
Key words：concrete，temperature matching，low activity，magnesium oxide，strain，elastic modulus