中文摘要：

将微观分析与宏观性能试验相结合，探讨钢纤维体积分数和纳米材料掺量对纤维纳米增强混凝土微观机理与物理力学性能的影响。根据复合材料力学理论，并结合相关文献试验结果的统计分析，建立了考虑纳米材料和纤维影响的纤维纳米混凝土强度计算模型。结果表明：在混凝土中掺入适量的纤维和纳米材料，改善了混凝土的微观结构，增加了混凝土的密实性，提高了混凝土的物理力学性能；随钢纤维体积分数从0％增大到1．5％，拌和物坍落度从40mm逐渐减小到25mm，纤维纳米混凝土抗压强度、劈拉强度和抗折强度分别提高12％，32％和12．5％；随着纳米SiO2掺量（质量分数）从0％增大到2％，拌和物坍落度减小95 mm，初凝、终凝时间分别减小52．3％和35．9％，纤维纳米混凝土抗压强度、劈拉强度和抗折强度分别提高9％，24％和14．7％；随着纳米CaCO3掺量从0％增大到2％，拌和物坍落度减小50 mm ，初凝、终凝时间分别减小35．2％和3．8％，纤维纳米混凝土抗压强度、劈拉强度和抗折强度分别提高8％，20％和8．8％。

英文摘要：

By combining the micro analysis and macro property experiments ,the effect of steel fiber volume fraction and nanosized material content on the micro mechanism and physical and mechanical properties of fiber and nanosized material reinforced concrete （FNMRC ） was investigated .Based on the mechanics theory of composite materials and the regression analysis of related literatures ,a model for strength calculation of FNMRC was proposed ,which considered the effect of nanosized materials and steel fiber .The results show that the suitable combined usage of nanosized materials with steel fiber improves the microstructure of concrete ,increases its densification and enhances the physical and mechanical properties .With the increase of steel fiber volume fraction from 0% to 1 .5% ,the mixture slump decrease from 40 mm to 25 mm ,and the compressive strength ,splitting tensile strength and flexural strength of FNMRC increase by 12% ,32% and 12 .5% ,respectively .With the increase of nano‐SiO2 content （mass fraction）＆nbsp;from 0% to 2% ,the mixture slump reduces 95 mm ,and the initial and final setting time reduce 52 .3% and 35 .9% ,respectively ,and the compressive strength ,splitting tensile strength and flexural strength of FNMRC increase 9% ,24% and 14 .7% ,respectively .With the increase of nano‐CaCO3 content from 0% to 2% ,the mixture slump reduces 50 mm ,and the initial and final setting time reduce 35 .2% and 3 .8% , respectively , and the compressive strength , splitting tensile strength and flexural strength of FNMRC increase 8% ,20% and 8 .8% ,respectively .