摘要
为了研究玻璃纤维网格和混杂纤维对超高性能混凝土(ultra-high performance concrete,UHPC)双向板弯曲性能的影响,通过四边简支板的弯曲试验,研究了玻璃纤维网格层数、单掺钢纤维(steel fiber,SF)、钢纤维分别与聚乙烯醇纤维(polyvinyl alcohol,PVA)、玻璃纤维(glass fiber,GF)、玄武岩纤维(basalt fiber,BF)混掺对UHPC板的破坏形态、承载力和弯曲韧性的影响.结果表明,未铺设网格的UHPC板中短切纤维总体积率为1.5%时,混杂1.0%SF和0.5%PVA(1.0%SF/0.5%PVA)纤维对UHPC板增强增韧最显著,其极限承载力和挠度10 mm处的能量吸收值较掺入1.5%SF、0.5%SF/1.0%PVA、0.5%SF/1.0%GF、0.5%SF/1.0%BF的UHPC板分别提升了33.7%、53.3%、43.2%、117.0%和14.3%、81.8%、46.1%、107.5%;单掺1.5%SF的UHPC板的延性和持荷能力较混杂纤维UHPC板强.相较未铺设玻璃纤维网格试件,玻璃纤维网格能够有效抑制UHPC板的主裂缝的萌生和扩展,并使板呈现变形硬化特征;铺设网格的UHPC板内部会发生显著的内力重分布,随着网格层数的增加,极限承载力和弯曲韧性显著提升;单掺1.5%SF的UHPC板承载力和能量吸收的增幅随着网格层数的增加逐渐降低;混杂纤维UHPC板随着网格层数的增加会发生显著的应变硬化行为.试验证实网格有效应力、利用率与网格层数呈负相关,抗弯承载力与网格层数呈正相关,其中1.0%SF和0.5%PVA纤维混杂使玻璃纤维网格利用率最高,对UHPC板抗弯承载力提升最显著.
To study the effects of the glass fiber net and hybrid fibers on the bending behavior of ultra-high performance concrete(UHPC)two-way slabs,bending tests of simply supported slabs were conducted on four sides.Effects of glass fiber net layers,single-doped steel fiber(SF),and steel fiber blended with polyvinyl alcohol(PVA),glass fiber(GF),and basalt fiber(BF)on the failure mode,bearing capacity,and flexural toughness of UHPC slabs were studied.Results show that the blending of 1.0%SF and 0.5%PVA(1.0%SF/0.5%PVA)fibers has the most considerable effect on the reinforcement and toughening of the UHPC slabs when the total content of shortcut fibers in the UHPC slab without grid is 1.5%.Compared with UHPC slabs doped with 1.5% SF,0.5%SF/1.0% PVA,0.5% SF/1.0% GF,0.5% SF/1.0% BF,and 0.5% SF/1.0% BF,the ultimate bearing capacity and energy absorption values at a deflection of 10 mm are increased by 33.7%,53.3%,43.2%,117.0% and 14.3%,81.8%,46.1%,and 107.5%,respectively.The ductility and maintained load capacity of UHPC slabs doped with 1.5% SF are greater than those of hybrid fiber UHPC slabs.Compared with specimens without a glass fiber net,the glass fiber net can effec-tively inhibit the initiation and propagation of main cracks in the UHPC slabs and allow the slabs to exhibit deforma-tion-hardening characteristics.The significant redistribution of internal forces occurs in UHPC slabs with a net ar-rangement,and the ultimate bearing capacity and flexural toughness considerably increase with the increase of net layers.The increase of bearing capacity and energy absorption of UHPC slabs doped with 1.5% SF gradually decreases with the increase of net layers.The strain hardening behavior of hybrid fiber UHPC slabs increases with the number of net layers.The test proves that the effective stress and utilization ratio of the net are negatively correlated with the number of layers of the net,whereas the bending bearing capacity is positively correlated with the number of layers of the net.The hybrid of 1.0% SF and 0.5% PVA fiber
作者
邓宗才
鹿宇浩
龚明高
桂营金
景晓斌
Deng Zongcai;Lu Yuhao;Gong Minggao;Gui Yingjin;Jing Xiaobin(Key Laboratory of Urban Security and Disaster Engineering(Beijing University of Technology),Ministry of Education,Beijing 100124,China;Beijing Huairen Qianjing Technology Co.,Ltd.,Beijing 102400,China)
出处
《天津大学学报（自然科学与工程技术版）》
EI
CAS
CSCD
北大核心
2022年第6期621-631,共11页
Journal of Tianjin University：Science and Technology
基金
北京市教委科技重点资助项目(KZ201810005008).
