常温养护型超高性能混凝土的弯曲性能表征方法

Characterize of flexural performance of Ultra-high Performance Concrete without thermal curing

摘要:

采用四点弯曲试验方法对常温养护超高性能混凝土（Ultra-high Performance Concrete, UHPC）的弯曲性能进行了试验研究，并在试验结果的基础上讨论了适于UHPC弯曲性能的评价方法。试验结果表明，UHPC没有明显的初裂点，但有明显的“挠度硬化”行为。结合不同钢纤维掺量下UHPC荷载-挠度关系曲线，分析总结了三种国外常用的弯曲性能评价方法(ASTM C1018法、JSCE SF4法和ASTM C1609法)的优点和不足。通过比较分析，ASTM C1609规定的不同挠度及其对应的弯曲强度给予了UHPC结构设计更为准确的指标，能满足UHPC结构设计的多种需求。

Abstract:

An experimental study on the flexural performance of ultra-high performance concrete (UHPC) without thermal curing was carried out via third-point bending tests. Based on the test results, discussions on how to effectively evaluate the flexural performance of UHPC were presented. The third-point bending test results indicated that first cracking point of UHPC was hard to be determined, while significant “deflection hardening” behavior was noticed. Combined with the load-deflection curves of UHPC with different steel fiber dosage, both advantages and disadvantages of three evaluation methods of ASTM C1018, JSCE SF4 and ASTM C1609 commonly used were discussed. The results showed that the flexural strength related to different mid-span deflections given by ASTM C1609 can be regarded as more meaningful parameters for UHPC structure design, which can meet the various needs of the UHPC structural design.