聚乙烯纤维和玄武岩纤维混合增强工程水泥基复合材料的喷射性能研究

Study on the Spraying Performance of Hybrid Polyethylene Fiber and Basalt Fiber Engineered Cementitious Composites

  • 摘要: 实现高延性纤维增强水泥基复合材料(ECC)的喷射施工具有较好的工程应用前景前景。本研究制备了一种新型聚乙烯(PE)纤维和玄武岩纤维(BF)混合增强工程水泥基复合材料(Hybrid-fiber ECC, HECC),通过流动度试验研究了纤维种类及掺量对HECC的工作性能变化规律,并划分了HECC可喷性能区间;采用直拉实验与抗压试验研究了喷射成型HECC的力学性能;通过界面直接拉拔试验验证了不同工况下HECC喷射加固既有混凝土界面的粘结性能。研究结果表明:HECC的流动度主要由更柔性更易团聚的PE纤维主导,在纤维掺量过大,流动度小于150 mm时不适宜喷射施工,喷射成型HECC具有应变硬化及特征,增大喷射压力可将由喷射引入缺陷导致的力学性能的降低控制在15%以内;在多种工况下HECC加固界面粘结强度接近,达到压抹施工的80%以上。

     

    Abstract: The use of Engineered Cementitious Composite (ECC) in sprayed applications presents promising prospects but imposes higher demands on material performance. A hybrid fiber-reinforced ECC (HECC) incorporating polyethylene (PE) fibers and basalt fibers (BF) was developed for sprayed applications. The study investigated the influence of different fiber types and dosages on the workability of HECC through flowability tests, thereby defining a sprayable performance range. The mechanical properties of sprayed HECC were examined using direct tension tests and compressive strength tests. Additionally, interface pull-off tests were conducted to evaluate the bond performance of HECC sprayed onto existing concrete under various conditions. The results indicated that the flowability of HECC is predominantly influenced by the more flexible and aggregating PE fibers. When the fiber dosage is excessive, leading to a flowability below 150 mm, the material becomes unsuitable for sprayed application. The sprayed HECC retains the characteristics of multi-point cracking and strain hardening, with increased spraying pressure enhancing its mechanical properties. Under various conditions, the bond strength of HECC at the interface approached that of existing concrete, achieving more than 80% of the strength obtained through press-mud construction.

     

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