钢-聚丙烯混杂纤维混凝土的真三轴强度试验研究

Experimental study of strength of steel-polypropylene hybrid fiber reinforced concrete subjected to true triaxial compression

考虑纤维种类、长径比、体积掺量3个主要影响因素,设计制作25组纤维混凝土试件,通过真三轴压缩试验,研究钢-聚丙烯混杂纤维混凝土（HyFRC）在不同围压条件下的强度及破坏模式.研究结果表明,在不同侧向围压作用下,HyFRC试件的破坏模式均为斜剪破坏.与相同配合比的素混凝土试件相比,随着钢纤维特征参数的增加,HyFRC试件的三轴峰值强度有显著提升,而聚丙烯纤维特征参数的变化对峰值强度影响较小.基于试验结果,提出了基于W-W 5参数模型的HyFRC破坏准则,能够很好地预测纤维混凝土在多轴压缩状态下的强度.

This paper deals with the traxial strengths and failure modes of steel-polypropylene fiber reinforced concrete（HyFRC）subjected to true triaxial compressions.A total of 25 groups of fiber reinforced concrete specimens including plain concrete were designed and fabricated.The main variables that considered in this study are fiber volume fraction and fiber aspect ratio.It is shown that,under different lateral pressure combinations,HyFRC demonstrated an inclined shear failure mode.In comparison to the plain concrete matrix,the triaxial peak strength increases considerably with the increase in the steel fiber reinforcement index,while the no legible improvement of triaxial strength was found with the addition of polypropylene fiber.Subsequently,a failure criterion based on Willam-Warnke five-parameter model was developed which accounts for the presence of hybrid fibres,and the prediction provides a close approximation of the ultimate strength of HyFRC under multiaxial compression.