碳纤维对纳米偏高岭土再生混凝土力学性能及微观结构试验研究

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中图分类号：TB9;TU528 文献标志码：A 文章编号：1674-5124（2025）06-0017-08

Experimental study on mechanical properties and microstructure of carbon fiber reinforced nano metakaolin recycled concrete

YAN Jie LUO Yan YU Xutao WANG Lijun WENG Weisu （College of Civil Engineering，Hebei UniversityofArchitecture， Zhangjiakou 0750oo， China）

Abstract： In order to study the efect of carbon fiber（CF）on the mechanical properties of nano metakaolin recycled concrete（NRAC）， orthogonal tests were conducted using the content of nano metakaolin（NMK）， CF content， the replacement rate of recycled coarse aggregate（RA） and the length of CF as influencing factors to studythe efects of CF on the compressive strength， tensile strength and tension-compression ratio of NRAC. The pore structure and micro-morphology of recycled concrete（RAC） were analyzed by mercury intrusion method and scanning electron microscope method， in order to find out the improvement mechanism of CF on NRAC.The results show that the replacement rate of RA and the content of NMK have significant effects on the compressive strength，and the content of CF has remarkable efects on the tensile strength and tensioncompression ratio. Considering the compressive strength，tensile strength and tension-compression ratio of recycled concrete， the optimal ratios are A3B4C1D2 A1B3C1D3 ， A1B3C4D3 ，respectively. The incorporation of CF increases the porosity of RAC，but the porosity increases only slightlydue to the presence of NMK.In addition， the separation and crack resistance effect of CF refine the pore structure of RAC.CF plays a bearing role through the bridge function， which makes the crack propagation path more complicated and is not easy to produce transverse cracks.Moreover，the filing effect and volcanic ash effect of NMK enhance the bond strength of the transition Zone of fiber-mortar interface，further play the strengthening role of CF，and thus improving the strength and ductility of RAC.

Keywords： carbon fiber; nano metakaolin recycled concrete; compressive strength; tensile strength; tensioncompression ratio; microstructure

0 引言

随着中国城市经济快速增长，在拆除重建过程中产生的废弃混凝土的再利用问题日益突显，由此再生混凝土（recycledconcrete，RAC）领域近年来成为研究热点。（剩余10029字）