钢纤维超高强混凝土动态力学性能

DYNAMIC MECHANICAL PROPERTIES OF STEEL-FIBER REINFORCED ULTRA HIGH STRENGTH CONCRETE

采用分离式霍普金森压杆装置对不同纤维体积率的钢纤维超高强混凝土进行不同应变率的冲击压缩试验,结果表明钢纤维超高强混凝土是应变率敏感材料,并测出其应变率敏感阀值,当应变率超过阀值后,钢纤维超高强混凝土的强度、韧度与弹性模量都随纤维体积率的增加而显著提高,在高应变率下,超高强混凝土基体成粉碎性破坏,而钢纤维超高强混凝土呈现出“裂而不散”的破坏形态。

The dynamic mechanical properties of steel-fiber reinforced ultra high strength concrete with different fiber volume fractions were studied by the split Hopkinson press bar testing method under impact compression with different strain rates. The experimental results show that the steel-fiber reinforced ultra high strength concrete is sensitive to strain rate. The relations between the mechanical properties of steel-fiber reinforced ultra high strength concrete and strain rates are examined. The threshold value of strain rate beyond which the strength, ductility and elastic modulus of steel fiber reinforced ultra high strength concrete is remarkably increased with the increase of the fiber volume fractions. The experiment also demonstrates that adding steel fibers into the ultra high strength concrete matrix has significant effects on the failure pattern of the concrete specimen. Under high strain rate, steel fiber reinforced ultra high strength concrete specimen developed cracks but the overall shape of the specimen remained virtually unaltered, however, under the same strain rate, the ultra high strength concrete matrix specimen without steel fibers were almost smashed into small pieces.