超高性能钢纤维增强水泥基复合材料的力学性能及微结构分析

Mechanical behavior and microstructure analysis of ultra-high performance steel fiber reinforced cementitious composites

系统研究了偏高岭土对超高性能钢纤维增强水泥基复合材料力学性能的影响规律,并采用XRD、纳米压痕、SEM等现代分析测试手段揭示该材料具有超高性能的微观机理.结果表明,掺加偏高岭土比不掺的试件在相同养护龄期、相同纤维掺量等条件下显示出更加优异的力学性能;超高性能钢纤维增强水泥基复合材料由于具有极低的低水胶比,其90 d水泥水化程度仅有65%左右,硬化水泥浆体中存在大量未水化的水泥颗粒,且绝大部分水化产物为UHD C-S-H凝胶;偏高岭土中存在大量的活性SiO2和Al2O3,可以促进水泥的水化,进一步填充了复合材料内部的空隙,使得材料整体的密实度得以提高,界面得以强化,从而使复合材料呈现出优异的力学性能.

The effects ofmetakaolin on the mechanical performance of ultra high performance steel fiber reinforced cementitious composite was studied. The microstructure evolution of the material was also studied via XRD, nanoindentation, SEM and other different analysis testing methods. The results indicate that the mechanical performance increased due to the addition ofmetakaolin at the same curing age and volume fraction of steel fiber, The hydration degree of the composite was only 65% at the curing age of 90 days because of the very low water-binder ratio. There were large amount ofunhydrated cement in the harden composite and most of hydrated products was UHD C-S-H. The active composites （SiO2 and Al2O3） in metakaolin can improve the hydration process and can also fill the micro cracks inside the cementitious composite, the structure then was densed and the interface was strengthened. So the composite has excellent mechanical performance.