修补砂浆抗盐冻性能的试验研究

Research on the durability of repair mortar against the wall of the bridge

季冻区水泥混凝土路面、桥梁防撞墙等部位常受到除冰盐引起的盐冻破坏,修补材料的抗盐冻性能影响修补工程的长期质量。制备了水泥基聚合物修补砂浆,通过掺加憎水剂和聚丙烯纤维来改善修补砂浆的抗渗性、韧性和体积稳定性,综合提升修补砂浆的抗盐冻性能。试验结果表明,掺加1.5%的有机硅憎水剂和0.2%的聚丙烯纤维均可明显提高修补砂浆的折压比,降低收缩率,使修补砂浆的抗裂能力得以提升;电通量降低明显,28次单面盐冻试验后,试件单位面积剥落物明显降低,修补砂浆的耐久性得到改善。

The freezing-thawing area of cement concrete pavement and bridge wall are often damaged by deicing salt,and the salt-resistance of the repairing material affects the long-term quality of the repairing project.Cement-based polymer mortar was prepared by adding hydrophobic agent and polypropylene fiber to improve the impermeability,toughness and volume stability of repair mortar,and comprehensively improve the resistance to freeze-thaw performance of repair mortar.The results show that the addition of 1.5% silicone water-repellent and 0.2% polypropylene fiber can significantly improve the ratio of flexural and compressive strength of repair mortar,reduce the shrinkage rate,so that the ability of mortar′ s resistance to cracking can be improved and the electric flux decreased obviously.After 28 times of single-salt freezing experiment,the exfoliation quantity per unit area of the specimen was obviously decreased,and the durability of repairing mortar was improved.