高铁梁面防水保护层C40细石纤维混凝土性能研究

Study on properties of waterproof protectivelayer C40 fine aggregate concrete for high speed railways

依据高铁梁面防水保护层C40细石纤维混凝土技术要求,对比研究了网状聚丙烯纤维、聚丙烯腈纤维、聚乙烯醇纤维及纤维素纤维对混凝土抗裂性能及拌合物性能的影响。试验结果表明:网状聚丙烯纤维和聚丙烯腈纤维均存在各自的局限性,网状聚丙烯纤维早期抗塑性开裂性能较差,而聚丙烯腈纤维早期抗塑性开裂性能较好,但严重影响混凝土施工性能;短切纤维素纤维在混凝土体系中很难搭接粗骨料和细骨料形成网络结构,抗塑性开裂效果一般;聚乙烯醇纤维分子结构中含有羟基,能与水泥水化产物发生反应,亲水性强,分散性好,具有较好抗裂性能,更适合用于高铁梁面防水保护层C40细石纤维混凝土。

According to the requirements of C40 fine aggregate concrete technology of waterproof protective layer for high speed rail-ways,the influence of the reticulate polypropylene fiber,polyacrylonitrile fiber,polyvinyl alcohol fiber and cellulose fiber on the properties of concrete anti-cracking performance and workability were studied.The results showed that the reticular polypropylene fiber and polyacry-lonitrile fiber had their limitations,the reticulate polypropylenefiber had little effect on concrete workability,but early plastic cracking re-sistance performance wasvery poor,polyacrylonitrile fiber early plastic cracking resistance performance was good,but seriously affected the construction of concrete performance.Short cellulose fiber in the concrete system was difficult to lap of coarse aggregate and fine aggre-gate to form network structure,and plastic cracking resistance effect was not very ideal.The molecular structure of polyvinyl alcohol fiber containing hydroxyl,could react with cement hydration products,powerful hydrophily,good dispersibility,had a good crack resistance,so more suitable for waterproof protective layer C40 fiber concrete with fine stones.