MgO膨胀剂对长龄期混凝土性能的影响  

Effect of MgO Expansive Agent on Properties of Long-Age Concrete

作　　者：卢存 李华[2,3] 徐文[2,3] 王育江[2,3] LU Cun;LI Hua;XU Wen;WANG Yujiang(State Key Laboratory of High Performance Civil Engineering Materials,Jiangsu Sobute New Materials Co.,Ltd.,Nanjing 211103,China;School of Materials Science and Engineering,Southeast University,Nanjing 211189,China;Jiangsu Research Institute of Building Science Co.,Ltd.,Nanjing 211108,China)

机构地区：[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

出　　处：《建筑材料学报》2023年第5期524-529,共6页Journal of Building Materials

基　　金：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)。

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.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.

关 键 词：MGO膨胀剂 混凝土 长期膨胀变形 微结构分析 

分 类 号：TU528.01[建筑科学—建筑技术科学]