| 摘要: |
| 采用钢纤维与粗聚烯烃纤维或细聚乙烯醇纤维混掺技术，制备了新型超高强度活性粉末混凝土(RPC)，以改善RPC的韧性及脆性；由弯曲试验测其荷载位移曲线，分析了纤维品种、掺量变化对新型RPC韧性的影响规律，并对比了在胶凝材料中添加超细水泥或硅灰所制备的RPC的韧性.结果表明：混掺纤维RPC的荷载位移曲线具有二次硬化特征；混掺纤维RPC的韧性指标明显高于单掺钢纤维RPC，以1%钢纤维体积分数与9kg/m3粗聚烯烃纤维混掺所制备的超细水泥RPC韧性指标T(7)比单掺钢纤维时提高70%；从经济性看，以1%钢纤维体积分数与粗聚烯烃纤维或细聚乙烯醇纤维混掺对RPC增韧效果更优；当钢纤维体积分数为2%时，细聚乙烯醇纤维掺量不宜高于9kg/m3；超细水泥RPC韧性优于硅灰RPC试件. |
| 关键词: 活性粉末混凝土 混掺纤维 弯曲韧性 二次硬化 硅灰 |
| DOI：103969/jissn1007 9629201502004 |
| 分类号: |
| 基金项目:国家自然科学基金资助项目(51378032);北京市自然科学基金资助项目（8142005） |
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| Experimental Study on the Flexural Toughness of RPC Reinforced by Hybrid Fibers |
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DENG Zongcai, DAUD Jumbe R
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Key Laboratory of Urban Security and Disaster Engineering, Ministry of Education,Beijing University of Technology, Beijing 100124, China
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| Abstract: |
| A flexural test was conducted to investigate the effectiveness of a new type of hybrid fibers reinforced reactive powder concrete(RPC), in which RPC was reinforced with a combination of steel fibers and macro polyolefin(PP) or micro polyvinyl alcohol(PVA) fibers in different quantities, to improve the toughness and brittleness performances of beams. Influences of different types and quantity of fiber on the toughness of RPC were compared with the specimens in which either ultra fine cement or silica fume was used. It is observed from the results of the experiment that the “secondary peak” characteristics of the load deflection curves are achieved, which are far much better than only using steel fibers in RPC. The toughness index is more significantly improved when steel fibers and PP or PVA fibers are used together in RPC than that in which only steel fiber is used. It is also observed that better results are achieved for ultra fine cement RPC specimens blended with 1% volume fraction steel fiber and 9kg/m3 PP fibers as compared with specimens blended with 1% steel fibers only, where the toughness index is significantly improved by 70%，and that the most economical configuration of fibers is that in which RPC is blended with 1% volume fraction steel fibers and PP or PVA fibers. When steel fiber volume fraction is 2%, it is advisable that the amount of micro PVA fibers should not exceed 9kg/m3; the toughness of ultra fine cement RPC is better than that of silica fume RPC. |
| Key words: reactive powder concrete(RPC) hybrid fiber flexural toughness secondary hardening silica fume |
