为改善碳纤维增强混凝土(CFRC)内部的纤维/基体(F/M)界面性能,提出利用碳纳米管-碳纤维跨尺度增强体(CNTs-CF)对F/M微观界面进行改性的技术方法。设计制作了CNTs-CF体积分数分别为0%、0.1%、0.2%、0.3%和0.4%的跨尺度纤维增强混凝土(CCFRC)试件,进而对其开展了劈裂抗拉实验,并与CFRC进行对比分析。结果表明,在相同的纤维掺量情况下,CCFRC能够在劈拉破坏失效时维持更好的整体性,而且CCFRC的劈裂抗拉强度明显高于CFRC。CCFRC的劈裂抗拉强度随纤维掺量的增加呈先逐渐升高后略有下降的变化趋势,当CNTs-CF的体积分数为0.3%时达到最大值,较之普通混凝土(PC)和CFRC,增长幅度分别达37.67%和13.21%。CNTs-CF兼具碳纤维和碳纳米管的优良特性,能够充分发挥跨尺度协同改性效应,强化F/M界面。CCFRC在工程结构抗力提升,以及基础设施电磁防护领域具有广阔的应用发展前景。
To improve the performance of fiber/matrix (F/M) interface in carbon fiber reinforced concrete (CFRC),a novel method was proposed to modify the F/M micro-interface using carbon nanotubes-carbon fiber cross-scale reinforcement (CNTs-CF).The cross-scale fiber-reinforced concrete (CCFRC) specimens with CNTs-CF volume fraction of 0%,0.1%,0.2%,0.3%,and 0.4% were designed and fabricated.The splitting tensile test was carried out on them and then compared with CFRC.The results showed that under the same fiber content,CCFRC could maintain better integrity when splitting tensile failure occurred,and the splitting tensile strength of CCFRC was significantly higher than that of CFRC.With the increase of fiber content,the splitting tensile strength of CCFRC increased gradually at first and then decreased slightly.When the volume fraction of CNTs-CF was 0.3%,the splitting tensile strength reached the maximum,which was 37.67% and 13.21% higher than that of plain concrete (PC) and CFRC,respectively.CNTs-CF had the excellent characteristics of carbon fiber and carbon nanotubes,which could give full play to the cross-scale synergistic modification effect and strengthen the adhesion between fiber and matrix.CCFRC has a promising prospect in the resistance improvement of engineering structure and electromagnetic protection of infrastructure.
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