聚丙烯纤维预拌混凝土抗盐冻耐久性研究

寒冷地区道路、桥梁混凝土结构常常遭受盐冻破坏,为改善混凝土的盐冻抵抗能力,该文研究添加引气剂和聚丙烯纤维的预拌混凝土抗盐冻耐久性能及混凝土浇筑全过程空隙分布特征。研究表明,混凝土中添加聚丙烯纤维,可改善冻融作用(盐冻侵蚀)引起的混凝土表面抗剥落性能。此外,随着振捣密实时间的增加,硬化混凝土中的微细气泡减少,粗大气泡增加。然而,这一变化对气泡间隔因子和混凝土表面抗剥落性能的影响较小。

The concrete structures of roads and bridges in cold regions often suffer from salt freezing damage.In order to improve the salt freezing resistance of concrete,this paper studied the salt freezing resistance of ready-mixed concrete added with air entraining agent and polypropylene fiber and the characteristics of void distribution during the entire process of concrete pouring.Research shows that adding polypropylene fibers to concrete can improve the anti peeling performance of concrete surface caused by freezing and thawing action(salt freezing attack).In addition,as the vibration compaction time increases,the fine bubbles in hardened concrete decrease,while the coarse bubbles increase.However,this change has little impact on the bubble spacing factor and the anti peeling performance of the concrete surface.