聚合物对砂浆热老化后防水及力学性能的影响  

Effects of Polymers on Waterproofing and Mechanical Properties of Mortar after Heat Treatment

作　　者：张娜 孙倩 张鹏宇 王冬梅 王琴 ZHANG Na;SUN Qian;ZHANG Pengyu;WANG Dongmei;WANG Qin(Tianjin Building Materials Science Research Academy Co.,Ltd.,Tianjin 300381,China;College of Civil and Transportation Engineering,Beijing University of Civil Engineering and Architecture,Beijing 100044,China)

机构地区：[1]天津市建筑材料科学研究院有限公司,天津300381 [2]北京建筑大学土木与交通工程学院,北京100044

出　　处：《硅酸盐通报》2023年第8期2703-2711,共9页Bulletin of the Chinese Ceramic Society

基　　金：天津市科技计划(22YFFCYS00070)。

摘　　要：将可再分散沥青粉末(EAP)、醋酸乙烯酯-乙烯共聚物(VAE)乳胶粉、苯乙烯-丙烯酸丁酯共聚物(SBA)乳液作为外加剂分别掺入水泥砂浆,通过热处理前后的吸水率测试、胶砂强度测试和微观形貌分析,研究了不同聚合物对水泥砂浆在70℃的耐热老化性能的影响。结果表明:试验采用的聚合物均可降低砂浆吸水率,且吸水率随聚合物掺量的增加而降低。SBA乳液的成膜性能优于粉体聚合物,因此SBA改性砂浆的表面防水效果最佳;两种可再分散聚合物粉末对比,同期热老化后EAP对砂浆防水改性效果优于VAE。经热老化后,沥青组分高温下具有一定的黏流性,EAP改性砂浆热老化后抗压强度降低,随EAP掺量增加,抗折强度先升高后降低,其强度变化主要体现为沥青组分在高温下的作用特点,VAE改性砂浆及SBA改性砂浆热老化初期聚合物膜结构阻碍水分迁移,热老化后期柔性的聚合物膜结构破坏造成强度高于热老化前的强度,其强度变化主要体现为传统聚合物改性砂浆的特点。In this paper,emulsified asphalt powder(EAP),VAE redispersible polymer powder,and SBA emulsion as admixtures were mixed into the cement mortar.Cement mortar strength,water absorption and SEM analysis before and after heat treatment were used to investigate the effect of addition of the three polymers on heat aging resistance of cement mortar at 70℃.The results show that the addition of three polymers can all decrease the water absorption,and the water absorption decreases with the increase of polymer content.The film-forming property of SBA emulsion is better than that of redispersible polymer powder,so its modified-mortar has the best surface waterproof effect.Compared with VAE,the effect of EAP on mortar waterproofing modification is better after heat treatment.After heat treatment,asphalt component has certain viscous flow at high temperature,and the compressive strength of EAP-modified mortar decreases after heat treatment,and the flexural strength increases first and then decreases with the increase of EAP admixture,and its strength changes mainly reflect the characteristics of asphalt components under high temperature,while those VAE-modified mortar and SBA-modified mortar mainly reflect the characteristics of traditional polymer modified mortar,the polymer film structure hinders moisture migration at the early stage of heat treatment,and the flexible polymer film structure breaks down at the later stage of heat treatment causing strength higher than that before thermal aging.

关 键 词：聚合物 水泥砂浆 耐热老化性能 沥青粉末 VAE SBA 

分 类 号：TU528[建筑科学—建筑技术科学]