摘要: |
通过三点弯曲断裂试验,研究了钢纤维、钢纤维粗聚烯烃纤维、钢纤维聚乙烯醇纤维以及钢纤维粗聚烯烃纤维聚乙烯醇纤维对活性粉末混凝土(RPC)断裂韧性的改善效果.结果表明:与单掺钢纤维的RPC试件相比,钢纤维与粗聚烯烃或聚乙烯醇纤维混掺增强RPC试件的预制裂缝尖端出现数条细小的微裂缝,其荷载挠度曲线和荷载裂缝口张开位移(CMOD)曲线均表现出明显的“二次硬化”现象;当钢纤维体积分数为15%,聚乙烯醇或粗聚烯烃纤维掺量为9kg/m3时的混杂纤维RPC试件与单掺钢纤维RPC试件相比,其峰值荷载分别提高了544%和854%,断裂能分别提高了1384%和885%,断裂韧度分别提高了1119%和508%;当钢纤维体积分数为10%,粗聚烯烃纤维和聚乙烯醇纤维掺量均为30kg/m3或45kg/m3时,钢纤维、粗聚烯烃和聚乙烯醇纤维混掺表现出良好的混杂效应;钢纤维体积分数为10%~15%,合成纤维总掺量为9kg/m3时,对RPC断裂性能的改善效果最理想. |
关键词: 活性粉末混凝土 混杂纤维 断裂能 断裂韧度 混杂效应 |
DOI:103969/j.issn1007 9629201601003 |
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);教育部博士点基金资助项目(20131103110017) |
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Fracture Properties of Hybrid Fibers Reinforced Reactive Powder Concrete |
DENG Zongcai, FENG Qi
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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: |
Fracture properties of reactive powder concrete (RPC) which was reinforced in steel fibers,steel macro polyolefin hybrid fibers and steel polyvinyl alcohol hybrid fibers were studied by three point bending fracture test to investigate the effect of hybrid fibers on the toughness of RPC. It is found that compared to RPC specimens reinforced only by steel fibers, the crack tip of RPC specimens reinforced by hybrid fibers shows some micro cracks, their load deflection curves and load CMOD curves show an obvious secondary hardening phenomenon; compared to RPC specimens reinforced only by steel fibers, the peak load of steel macro polyolefin hybrid fibers RPC specimens and steel polyvinyl alcohol hybrid fibers RPC specimens increa ses by 544% and 854%, and fracture energy increases by 1384% and 885%, and fracture toughness improves by 1119% and 508% respectively, when steel fibers volume fraction is 15% and content of macro polyolefin fiber or polyvinyl alcohol fibers is 9kg/m3; specimens reinforced by three kinds of fibers show a perfect hybrid effect when the steel fibers volume fraction is 10%, while macro polyolefin fiber and polyvinyl alcohol fibers content is 30kg/m3 or 45kg/m3 separately; fracture properties of RPC show a significant improvement when steel fibers volume fraction is 10%15% and synthetic fibers content is 9kg/m3. |
Key words: reactive powder concrete(RPC) hybrid fiber fracture energy fracture toughness hybrid effect |