MgO膨胀剂对长龄期混凝土性能的影响
作者:
作者单位:

1.江苏苏博特新材料股份有限公司 高性能土木工程材料国家重点实验室,江苏 南京 211103;2.东南大学 材料科学与工程学院,江苏 南京 211189;3.江苏省建筑科学研究院有限公司,江苏 南京 210008

作者简介:

卢 存(1995—),男,江苏南通人, 江苏苏博特新材料股份有限公司工程师,硕士. E-mail: lucun@cnjsjk.cn

通讯作者:

卢 存(1995—),男,江苏南通人, 江苏苏博特新材料股份有限公司工程师,硕士. E-mail: lucun@cnjsjk.cn

中图分类号:

TU528.01

基金项目:

国家自然科学基金资助项目(51738004, 52008189); 江苏省自然科学基金资助项目(BK20221198); 江苏省交通运输科技与成果转化项目(WCSN-KY1)


Effect of MgO Expansive Agent on Properties of Long-Age Concrete
Author:
Affiliation:

1.State Key Laboratory of High Performance Civil Engineering Materials, Jiangsu Sobute New Materials Co., Ltd., Nanjing 211103, China;2.School of Materials Science and Engineering, Southeast University, Nanjing 211189, China;3.Jiangsu Research Institute of Building Science Co., Ltd., Nanjing 211108, China

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    摘要:

    在模拟实际工程变温条件下,对掺MgO膨胀剂混凝土的长期变形性能及微观形貌进行了跟踪监测,并表征了其在80 ℃高温养护下的变形性能.结果表明:在经历早期变温历程及后期常温养护条件下,MgO膨胀剂在混凝土中的补偿收缩性能随着MgO掺量的增加而增大,活性值高的MgO对混凝土的补偿收缩效能更为显著;当常温养护3.0 a时,掺MgO膨胀剂混凝土的变形基本稳定;在80 ℃高温密封养护条件下,3.5 a龄期以上的掺MgO膨胀剂混凝土相较基准混凝土未出现膨胀现象,甚至略有收缩;随着养护龄期的延长,混凝土中MgO颗粒与周围水泥浆体间的分界面呈现逐步融合的特征,MgO颗粒内部O、Mg原子比呈现逐渐上升的趋势.

    Abstract:

    The long-term deformation performance and microscopic morphology of concrete mixed with MgO expansive agent were monitored under simulated variable temperature conditions of actual engineer, and their deformation performance under high temperature of 80 ℃ was characterized. The results show that the compensatory shrinkage performance of MgO expansive agent in concrete increase with the increase of MgO dosing under the early variable temperature course and later ambient temperature curing conditions. The compensatory shrinkage performance of concrete with high activity value MgO is more significant. When curing at ambient temperature of 3.0 years, compared with the base concrete, the deformation of concrete mixed with MgO expansive agent is basically stable. Under the high temperature condition of 80 ℃, concrete mixed with MgO expansive agent above the age of 3.5 years does not show expansion phenomenon, or even slightly contracted. With the increase of curing age, the partition interface between MgO particles and the surrounding cement paste in the concrete show a gradual integration, and the O and Mg atomic ratios in MgO particles show a gradually increasing trend.

    图1 变温条件下混凝土的早期变形Fig.1 Early deformation of concretes under various temperature conditions
    图2 混凝土的长期变形Fig.2 Long-term deformation of concretes
    图3 MgO混凝土的补偿收缩值Fig.3 Compensation shrinkage value of concretes mixed with MgO expansive agent
    图4 80 ℃高温密封养护下混凝土的变形Fig.4 Deformation of concrete under high temperature sealing curing at 80 ℃
    图5 C28 d40-MgO120-6.0浆体区域的BSE图片Fig.5 BSE image of C28 d40-MgO120-6.0 paste area
    图6 掺MgO膨胀剂混凝土中MgO颗粒区域能谱图Fig.6 EDS patterns of MgO particle area in concretes mixed with MgO expansive agent
    表 2 混凝土的配合比Table 2 Mix proportions of concretes
    表 1 MgO膨胀剂的化学组成Table 1 Chemical compositions of MgO expansive agents
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卢存,李华,徐文,王育江.MgO膨胀剂对长龄期混凝土性能的影响[J].建筑材料学报,2023,26(5):524-529

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  • 收稿日期:2022-05-12
  • 最后修改日期:2022-06-16
  • 在线发布日期: 2023-06-08
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