聚氨酯防水保温材料对混凝土抗冻性能的影响

Effects of polyurethane coating on concrete freezing resistance

混凝土抗冻性作为其耐久性的重要指标之一,被工程界广泛关注。其冻融破坏主要是由于混凝土材料与水接触时在正负交替温度作用下发生剥蚀。我国北方寒冷地区诸多水利工程遭受冻融破坏,对工程安全运行产生不利影响。聚氨酯材料具有防水保温性能,能够将内部的混凝土试件与外界隔离开,降低了温度和水的影响。本文通过对冻融后混凝土的宏观力学特性及微观结构的观测,验证了聚氨酯材料的防水保温特性对提高混凝土材料的抗冻性非常有利。喷涂聚氨酯的混凝土试件在经受冻融循环之后,内部含水量比普通试件少,动弹性模量下降幅度小,其微观结构较之普通试件更为密实。

Concrete freezing resistance,one of the key durability indices,is highly concerned in engineering field.Concrete is subject to surface erosion called freeze-thaw damage while in contact with water under a changeable temperature crossing zero.Many hydraulic projects in north China suffer freeze-thaw damage that often causes an unfavorable effect on project safety.Polyurethane material has good waterproof and thermal insulation properties and can reduce the effect of temperature and water on concrete material by isolating it from its external environments.This paper presents a verification of the polyurethane coating in improving concrete freezing resistance through experimental observation on the mechanical properties and SEM scanning on the microstructure of concrete specimens.The results show that after freeze-thaw test the concrete specimens sprayed with polyurethane has lower water content than the non-treated specimens and that their dynamic elastic modulus decreases more slowly.In addition,the treatment made microstructure more compact.