含粗骨料超高性能混凝土的单轴受拉力学性能

Uniaxial Tensile Behavior of Ultra-high Performance Concrete Containing Coarse Aggregate

关键词:  超高性能混凝土  粗骨料  应力-应变关系  纤维增强机理

Key words:  ultra-high performance concrete  coarse aggregate  stress-strain relation  fiber-reinforced mechanism

摘要:

考虑粗骨料掺量、钢纤维掺量及长径比等因素，研究了含粗骨料超高性能混凝土（UHPC-CA）的单轴受拉力学性能，揭示了纤维增强的机理和粗骨料的作用机制.结果表明：随着粗骨料掺量的增加，UHPC-CA的单轴抗拉强度与变形性能均下降；钢纤维掺量增加、长径比增大对UHPC-CA的受拉力学性能有较大的提升作用；钢纤维与基体间具有良好的握裹力，在基体内出现裂缝后，主要依靠握裹作用承受拉应力；粗骨料的掺入削弱了钢纤维空间分布的均匀性，同时引入了薄弱的粗骨料-基体界面过渡区，对UHPC-CA的受拉性能产生了不利的影响.

Abstract:

The uniaxial tensile behavior of ultra-high performance concrete containing coarse aggregate（UHPC-CA） was experimentally studied. The coarse aggregate content， steel fiber content and aspect ratio were selected as the main variables. The acting mechanisms of steel fiber and coarse aggregate were revealed. The results show that the uniaxial tensile strength and deformation performance of UHPC-CA decrease with the increase in coarse aggregate content， while the increase in steel fiber content and aspect ratio has a great enhancement effect on the tensile properties of UHPC-CA. There is a good interfacial bonding strength between the steel fiber and matrix. After cracks occur in the matrix， the tensile stress is mainly borne by the bonding force. The incorporation of coarse aggregate weakens the uniformity of the spatial distribution of steel fibers， and introduces the weak coarse aggregate-matrix interfacial transition zones， which adversely affect the tensile properties of UHPC-CA.