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室外环境对混凝土墙中轻烧MgO膨胀剂变形的影响
作者：余兰清1，陆加越1，李炜1，邓敏2
（1.高性能土木工程材料国家重点实验室，江苏苏博特新材料有限公司，江苏 南京 211103；2.南京工业大学 材料科学与工程学院，江苏 南京 211816）
摘要：将3种不同活性值（60 s、140 s和220 s）的轻烧MgO膨胀剂（MEA）掺入到混凝土墙中，监测室外条件下混凝土的变形及温湿度，测试净浆中MEA的水化程度，研究室外条件对混凝土墙中轻烧MEA水化变形的影响。结果表明：MEA的水化与变形主要集中在自浇筑到温降结束的早期阶段（0~10 d），膨胀量为100~180 με，并且其早期阶段的膨胀效能取决于活性值和温度的协同影响；而在温降结束后的后期阶段，所有MEA膨胀均明显减缓，膨胀量为30~80 με。春季浇筑条件下MEA-220和MEA-140的后期膨胀能力优于MEA-60，但在夏季浇筑条件下，3种不同活性的MEA后期膨胀均趋于停止。
关键词：工民建工程；混凝土墙；室外条件；轻烧氧化镁膨胀剂；变形
中图分类号：TU528.042 文献标识码：A 文章编号：1001-702X（2021）02-0047-05
Effects of outdoor condition on the deformation of lightly burnt MgO expansive agent added into concrete wall
YU Lanqing1，LU Jiayue1，LI Wei1，DENG Min2
（1.State Key Laboratory of High Performance Civil Engineering Materials，Jiangsu Sobute New Materials Co. Ltd.，Nanjing 211103，China；2.College of Materials Science and Engineering，Nanjing Tech University，Nanjing 211816，China）
Abstract：Three kinds of lightly burnt MEA with different activity（60 s，140 s and 220 s） were selected and added into concrete wall. The temperature，humidity and volume deformation of field concrete were monitored and hydration degree of MEA curing in the field concrete was measured，then effects of outdoor condition on the deformation of lightly burnt MEA in the concrete wall were investigated. The results indicated that the expansive deformation of lightly burnt MEA was mainly concentrated on the stage from casting to end of the fall temperature（0~10 d），the expansive deformation was 100~180 με，then，the expansive deformation of lightly burnt MEA was effect synergistically by temperature and hydration reactivity of MEA. After the end of fall temperature stage，expansive rate of three kinds of lightly burnt MEA declined obviously，the expansive deformation was 30~80 με. When poured in the spring，MEA-140 and MEA-220 showed larger expansion than MEA-60，but expansive deformation of three kinds of lightly burnt MEA all stopped when poured in the summer.
Key words：civil engineering construction，concrete wall，outdoor condition，lightly burnt MgO expansive agent，deformation