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自然养护条件下掺MgO膨胀剂混凝土的性能
作者：刘猛1，向飞1，王海龙1，程福星1，万鹏程1，莫立武2
（1．武汉三源特种建材有限责任公司，湖北 武汉 430000；2．南京工业大学，江苏 南京 210000）
摘要：研究了自然养护条件下掺不同活性MgO膨胀剂（MEA）混凝土的膨胀性能、力学性能和孔结构，采用QXRD定量分析了不同龄期内MEA的水化程度。结果表明：自然养护条件下，掺MEA混凝土的收缩值明显小于基准混凝土，MEA活性越高，产生的膨胀量越大，180 d时基准混凝土的收缩变形量为-157 με，掺6%MEA-120s、MEA-210s和MEA-260s混凝土相对基准混凝土的膨胀
量分别为193 με、98 με和93 με；60 d时掺6%MEA-120s混凝土的强度较基准混凝土提高了6%，掺6%MEA-120s混凝土、MEA-210s和MEA-260s混凝土的可渗透孔隙率较基准混凝土分别降低了20%、10%和8%，MEA的掺入能够有效改善混凝土的孔结构，降低混凝土的可渗透孔隙率，从而提高混凝土的强度；自然条件下，温度和相对湿度对MEA的水化速率有明显影响。180 d时，MEA-120s、MEA-210s和MEA-260s在混凝土中的水化程度分别为78%、66%和52%。
关键词：自然养护；MgO膨胀剂；混凝土；性能；水化程度
中图分类号：TU528.042+.4 文献标识码：A 文章编号：1001-702X（2019）11-0046-04
The performance of concrete containing MgO expansive agent under natural curing condition
LIU Meng1，XIANG Fei1，WANG Hailong1，CHENG Fuxing1，WAN Pengcheng1，MO Liwu2
（1.Sanyuan Special Building Materials Co. Ltd.，Wuhan 430000，China；2．Nanjing Tech University，Nanjing 210000，China）
Abstract：The expansion，compressive strength and pore structure of concrete containing MEA were investigated in this paper. Furthermore，the hydration degree of MEA with different activities were quantitatively analyzed by QXRD. The results showed that in natural condition，the deformation of concrete containing MEA was evidently lager than reference，and the higher the activity，the lager the deformation. The shrinkage deformation of reference concrete at 180 d was -157 με，while the expansion deformation of concrete containing 6% MEA-120s，MEA-210s and MEA-260s were 193 με，98 με and 93 με，respectively. Compared with reference，the compressive strength of concrete containing 6% MEA-120s was increased by 6%，and the total porosity of concrete containing 6% MEA-120s，MEA-210s and MEA-260s at 60 d were reduced by 20%，10% and 8%. MEA could efficiently improve the pore structure of concrete，decrease the total porosity，and thus enhance the compressive strength. In natural curing condition，the temperature and relative humidity had a significant effect on the hydration of MEA，the hydration degree of MEA-120s，MEA-210s and MEA-260s at 180 d were 78%，66% and 52%.
Key words：natural curing condition，MgO expansive agent，concrete，performance，hydration degree