引气剂对玻化微珠保温砂浆长期干燥收缩的影响

发布时间：2018-01-16 22:02

本文关键词：引气剂对玻化微珠保温砂浆长期干燥收缩的影响　出处：《建筑材料学报》2016年01期 　论文类型：期刊论文

【摘要】：应用立式比长仪测试了玻化微珠保温砂浆长期(2a)干燥收缩,研究了引气剂掺量(质量分数,下同)对保温砂浆干燥收缩的影响;用称重法测试了保温砂浆的质量损失,以反映其失水程度;采用氮吸附法测试了保温砂浆的孔结构,探讨了其干燥收缩、失水程度与孔结构之间的关系.结果表明,保温砂浆的干燥收缩随龄期增长呈快速期(7d前)-慢速期(7~365d)-亚稳定期(365d后)三阶段发展特征,引气剂的加入没有从根本上改变这种三阶段式的发展趋势,但显著抑制了后两个阶段的干燥收缩幅度;第一阶段干燥收缩的快速发展主要是由保温砂浆快速失水造成的,而第二、三阶段的干燥收缩主要归结于硬化浆体中小于50.0nm,尤其是7.3~12.3nm的孔体积分数明显增加;引气剂的作用与其掺量成正比,但掺量过大时因其不再增加引气作用而不能对保温砂浆的干燥收缩产生更大影响.
[Abstract]:The drying shrinkage of vitrified microbead insulation mortar for a long time was measured by using a vertical length ratio meter, and the effect of air entraining agent (mass fraction) on drying shrinkage of insulating mortar was studied. The mass loss of thermal insulation mortar was measured by weighing method to reflect the degree of water loss. The pore structure of insulating mortar was measured by nitrogen adsorption method, and the relationship between the drying shrinkage, the degree of water loss and the pore structure was discussed. The drying shrinkage of thermal insulation mortar is characterized by three stages with the increase of age, from 7 days before the rapid stage to 365d after the substable stage) from 7 days before the rapid stage to 365d after the slow stage. The addition of air entraining agent did not fundamentally change the development trend of this three-stage model, but significantly inhibited the drying shrinkage of the latter two stages. The rapid development of drying shrinkage in the first stage is mainly caused by the rapid water loss of the insulating mortar, while the drying shrinkage in the second and third stage is mainly attributed to less than 50.0 nm in the hardened mortar. In particular, the volume fraction of the pore at 7.3 ~ 12.3 nm increased obviously. The effect of air-entraining agent is proportional to the amount of air entraining agent, but when the amount of air entraining agent is too high, it can not have a greater effect on drying shrinkage of insulating mortar because it no longer increases the air-entraining effect.
【作者单位】：同济大学材料科学与工程学院;佳木斯大学材料科学与工程学院;
【基金】：“十二五”国家科技支撑计划项目(2012BA20B02) 中央高校基本科研业务费专项资金资助项目(050.00219164) 同济大学开放测试基金资助项目(0002013009)
【分类号】：TU578.1
【正文快照】： 玻化微珠保温砂浆的干燥收缩是用来评估由其构成的墙面或地面在使用期间是否发生开裂损伤的一个重要因素,且是一个长期发展过程.邓义群[1]采用神经网络,利用2a实测数据预测10a后玻化微珠保温砂浆仍未终止干燥收缩.朱永超[2]发现引气剂能显著降低玻化微珠保温砂浆28d干燥收缩.

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