纤维保水效应对失水成型水泥基材料强度的影响

The Influence of Fiber's Water Holding Effect on the Strength of Cement-based Materials Molded Through Water Losing

通过室内自然失水成型和恒温干燥失水成型水泥基材料的强度试验,研究了聚丙烯纤维的保水效应对水泥基材料弯拉强度的影响。结果表明：与保湿成型养护相比,失水成型条件下普通水泥基材料的早期强度下降显著,而失水成型聚丙烯纤维水泥基材料的强度则降低较小;在相同失水环境下,聚丙烯纤维水泥基材料的早期强度相对普通组可提高30%~40%,纤维的保水效应及其对水泥基材料的增强作用显著。此外,纤维的保水、增强效果会随纤维体积掺量的不同而不同,就文中水泥净浆组的研究结果而言（纤维长为9mm）,纤维体积掺量为0.4%时的增强效果最佳,然后依次是0.3%和0.1%,而纤维体积掺量为0.2%时的效果最差。

Based on strength tests of the cement-based materials under indoor natural water losing and constant temperature water losing conditions, the influence of fibels water holding effect on the flexural strength of cement-based materials was studied. The experimental results show that, comparing with that of the cement-based materials at moisture perseveration and curing, the early strength of ordinary cement-based material under water losing condition decreases substantially, while that of the cement-based materials reinforced by polypropylene fiber under water losing condition only decreases slightly. Under the same water losing condition, the early strength of latter improves by 30%-40% compared with that of the former, and the water holding effect of fiber and its enhancement to the cement-based materials are remarkable. Meanwhile, the water holding and the enhancement effect of fiber vary with its different volume contents. As to the results from the group made of cement paste （the fiber is 9 mm in length）, the fiber＇s enhancement effect is the best when its volume content is 0. 4%, and followed by 0. 3% and 0. 1%. When the volume content is 0. 2%, the en- hancement effect is the worst.