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MgO膨胀剂在大藤峡水电枢纽的应用效果监测

作者：黄志讲1，2，陆安群1，2，徐文1，2

关键字：MgO,膨胀,剂,在,大藤,峡,水电,枢纽,的,应用,

　
（1.高性能土木工程材料国家重点实验室，江苏省建筑科学研究院，江苏 南京  210008；
2.江苏苏博特新材料股份有限公司，江苏 南京  211103）
    摘要：结合大藤峡水电枢纽工程的混凝土特点，研究了MgO膨胀剂对大藤峡坝体29#仓、厂房底板36#仓的C25混凝土补偿收缩效果。结果表明，内掺4.5%活性值为140 s的MgO膨胀剂能够有效抑制C25水工混凝土的收缩变形，坝体C25混凝土温升阶段最大膨胀为145.8 με，坝体温降阶段最大收缩为110.5 με，厂房底板结构中的C25混凝土上部约束较小，最大膨胀约为200 με，下部约束较大，最大膨胀约为125 με；温降阶段，混凝土降温缓慢且温度基本高于30 ℃，MgO持续补偿温降收缩，最大收缩约为50 με；当上部仓浇筑后，各测点应变都随着混凝土温度升高而产生膨胀，后期基本处于平稳状态，混凝土整体处于膨胀状态。
    关键词：MgO膨胀剂；C25混凝土；坝体；厂房；变形
    中图分类号：TU592        文献标识码：A        文章编号：1001-702X（2021）02-0120-04
 
Monitoring of application effect of MgO expansion agent in Datengxia hydropower project
HUANG Zhijiang1，2，LU Anqun1，2，XU Wen1，2
（1.State Key Laboratory of High Performance Civil Engineering Materials，Jiangsu Academy of Building Research，Nanjing 210008，China；2.Jiangsu Subote New Materials Co. Ltd.，Nanjing 211103，China）
    Abstract：Based on the concrete characteristics of the Datengxia Hydropower Project， effect of MgO expansion agent on the shrinkage compensation of C25 concrete in the No.29 warehouse of the Datengxia Dam and No.36 warehouse of the factory floor were investigated. The results show that the MgO expansion agent mixed with 4.5% and the activity value of 140 s can effectively inhibit the shrinkage and deformation of C25 hydraulic concrete. The maximum expansion of the C25 concrete at the temperature rise stage is 145.8 με，the maximum shrinkage of the dam during the temperature drop phase is 110.5 με. In the floor structure of the factory building，the upper limit of C25 concrete is smaller， the maximum expansion is about 200 με，the lower limit is larger，and the maximum expansion is about 125 με. During the temperature drop period，the temperature of the concrete drops slowly and the temperature is basically greater than 30 ℃. MgO continuously compensates for the temperature drop shrinkage，and the maximum shrinkage is about 50 με，when the upper warehouse is poured， the strain at each measurement point will expand as the temperature of the concrete rises，and the latter will  be basically in a stable state，the concrete is in a state of expansion.
    Key words：MgO expansive agent，C25 concrete，dam，factory，deformation