马河水库溢洪道干喷纤维混凝土加固工程研究

根据喷射混凝土的施工工艺,采用现场喷制试件的方法,研究了加固马河水库溢洪道所用干喷聚丙烯纤维混凝土的塑裂性能,用切割法制作试件,研究了喷射纤维混凝土的抗冻性以及冻融循环对纤维混凝土与浆砌石界面黏结强度的影响.试验结果表明:低掺量聚丙烯纤维可抑制混凝土塑裂,提高抗冻融循环能力;干喷纤维混凝土与浆砌石之间的劈裂黏结强度随时间的延长而提高,且受冻融循环影响很小;选择合适的材料和施工工艺,可有效地降低干喷纤维混凝土的回弹率.

Strengthening of spillway for Mahe Reservoir with dry-sprayed polypropylene fiber concrete

The plastic cracking performance of dry-sprayed polypropylene fiber concrete used for strengthening the spillway of Mahe Reservoir was studied by in situ spraying of concrete samples. The results indicate that the mixing with low content of polypropylene fiber can reduce the plastic shrinkage and improve the freeze-thaw durability of sprayed concrete, and that the bond strength of the interface between sprayed fiber concrete and the stone blocks increases with time, while it is little affected by freeze-thaw cycling. It is also concluded that the rebound rate of dry-sprayed fiber concrete can be reduced obviously by adoption of rational materials and techniques.