基于磁场定向钢纤维的高性能混凝土性能研究

Performance of High Performance Concrete Based onMagnetic Field Oriented Steel Fiber

本文利用磁铁设计了一种高性能混凝土中钢纤维的定向方法,通过改变减水剂掺量调节混凝土的工作性能,研究了钢纤维定向效果与混凝土流变性能、力学性能的关系。结果表明,随着聚羧酸减水剂质量分数增大,混凝土屈服应力和塑性黏度逐渐降低,流动度增大。当减水剂质量分数大于2.5%后,屈服应力和流动度逐渐趋于稳定,但塑性黏度仍保持降低趋势。屈服应力和塑性黏度越低,纤维定向效果越好。未定向的钢纤维方向系数在0.479~0.526,而在磁场作用下定向的钢纤维方向系数为0.815~0.912,掺入定向钢纤维后混凝土抗折强度提升了24.0%~43.3%,韧性指数I_(20)提升了38.4%~69.9%。此外,磁场对钢纤维分散性没有明显影响,定向试件与未定向试件的抗压强度无明显差异。

In this paper,a directional method of steel fiber in high performance concrete was designed by using magnet.The working performance of concrete was adjusted by changing the amount of water reducing agent.The relationship between the directional effect of steel fiber and the rheological properties and mechanical properties of concrete was studied.The results show that with the increase of mass fraction of polycarboxylate superplasticizer,the yield stress and plastic viscosity of concrete decrease gradually,and the fluidity increases.When the mass fraction of water reducer is greater than 2.5%,the yield stress and fluidity gradually tend to be stable,but the plastic viscosity still maintains a decreasing trend.The lower the yield stress and plastic viscosity is,the better the fiber orientation effect is.The directional coefficient of unoriented steel fiber is 0.479~0.526,while the directional coefficient of steel fiber under magnetic field is 0.815~0.912.The flexural strength of concrete with oriented steel fiber increases by 24.0%~43.3%,and the toughness index I_(20) increases by 38.4%~69.9%.In addition,the magnetic field has no obvious effect on the dispersion of steel fiber,and there is no significant difference in compressive strength between oriented specimen and unoriented specimen.