寒区掺聚丙烯纤维桥面铺装防水性能研究

桥面铺装参与主梁受力,直接与车辆荷载及大气相接触,对桥梁的作用重大。铺装层一旦出现裂缝,雨水就会顺着缝隙进入桥梁内部,使混凝土强度降低、钢筋锈蚀,北方寒区会产生冻融破坏,所以减少裂缝的产生是提高铺装层防水性能的重要途径。在混凝土内掺入聚丙烯纤维可以抑制早期干缩裂缝及离析裂缝的产生和发展。本文研究低掺聚丙烯纤维混凝土配合比设计方法,并进行抗裂性试验,分析聚丙烯纤维混凝土防水机理,提出寒区掺入量范围。

Research on Waterproof Performance of Bridge Flooring Mixing the Polypropylene Fiber in Cold Areas

The bridge flooring that plays as the role of receiving the strength with beam directly contacting with the vehicles load and the atmosphere is significant to the bridge function. Once the crack appears in the flooring, the rain water can enter the bridge, which can cause the concrete intensity to be reduced and the steel bars to be rusted and eclipsed. Freeze-thaw damage will appear in northern cold areas and reducing crack is an important way of enhancing flooring waterproof performance of the bridge flooring. Therefore mixing the polypropylene fiber into the concrete may suppress crack production and the development caused by the early dryly shrinks and the segregation. The proportion design method of the lowly mixing polypropylene fiber concrete was studied and the crack resistance experiment was conducted. Then the polypropylene fiber concrete waterproof mechanism was ana- lyzed and the mixing propertion scope in the cold area was proposed.