混杂纤维对高性能混凝土高温性能的影响

针对高性能混凝土的防火、抗爆裂性能低的特点，采用低熔点（聚丙烯纤维）及高熔点纤维（钢纤维）混杂的方法，对高性能混凝土高温性能（抗折强度、抗压强度及劈裂抗拉强度，抗爆裂性能）进行改善．研究表明，800℃时，混杂纤维混凝土的抗折强度剩余率约15％，明显高于基准混凝土的抗折强度剩余率（约6％）；抗压强度剩余率约15％，与基准混凝土的强度剩余率相当（约15％）；劈裂抗拉强度剩余率约20％，明显高于基准混凝土的抗折强度剩余率（约10％）．另外混杂纤维明显提高了混凝土的抗爆裂性能，同时分析了混杂纤维改善高性能混凝土高温性能的作用机理．

Effects of Hybrid Fiber on High Performance Concrete Properties under High Temperature

The effects of hybrid fiber on high performance concrete properties under high temperature were studied.The experiment applies hybrid fiber with low(polypropylene fiber) and high melting point(steel fiber) to improve mechanics properties and spalling resistance of high performance concrete,since high performance concrete easily spallings and destroys when on fire.The results show that flexural strength residual ratio of hybrid fiber reinforced concrete(about 15%) is higher than that of normal concrete(about 6%);compressive strength residual ratio of hybrid fiber reinforced concrete(about 15%) is approximate to that of normal concrete(about 15%);splitting tensile strength residual ratio of hybrid fiber reinforced concrete(about 20%) is higher than that of normal concrete(about 10%).Hybridfiber significantly improves the spalling resistance of concrete.Also analyzed is the active mechanism through which hybrid fiber improves high performance concrete.