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超高韧性水泥基复合材料力学性能及早期收缩研究

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研究了水胶比和聚乙烯(PE)纤维掺量对超高韧性水泥基复合材料(UHTCC)抗压和抗折强度、弯曲韧性以及早期收缩性能的影响,并结合扫描电子显微镜(SEM)分析了UHTCC的微观结构.结果表明:随着水胶比的增大,UHTCC抗压和抗折强度均降低,而其弯曲韧性呈先降低后增长的变化趋势;增大PE纤维掺量可以显著提升UHTCC抗折强度和弯曲韧性,但会降低其3 d抗压强度,增大其7 d和 28 d抗压强度.在早期收缩性能方面,水胶比增大会降低UHTCC早期自收缩,但其早期干燥收缩有所增大.而UHTCC早期自收缩和干燥收缩均随PE纤维掺量的增大而降低.微观结构分析发现PE纤维掺量增大容易导致纤维团聚;水胶比的增大会降低UHTCC基体的密实度和纤维-基体界面黏结力,不利于UHTCC力学性能的发展.
Study on mechanical properties and early shrinkage of ultra-high toughness cementitious composites
The effects of water to binder ratio and polyethylene(PE)fiber content on the compressive and flexural strength,bending toughness and early shrinkage properties of ultra-high toughness cementitious composites(UHTCC)were investigated,and analyzed the microstructure of UHTCC with scanning electron microscopy(SEM).The results showed that with the increase of water to binder ratio,the compressive and flexural strength of UHTCC decreases,and its bending toughness shows a trend of decreasing and then increasing.The in-crease of PE fiber content could significantly improve the flexural strength and bending toughness of UHTCC,but will reduce its 3 d com-pressive strength and increase its 7 d and 28 d compressive strength.In terms of early shrinkage performance,the increase of water to binder ratio would reduce the early autogenous shrinkage of UHTCC,but its early drying shrinkage increased.The early autogenous shrinkage and early drying shrinkage of UHTCC decreased with the increase of PE fiber content.The microstructure analysis showed that the increase of PE fiber content was easy to lead to fiber agglomeration.The increase of water to binder ratio would reduce the compactness of UHTCC matrix and the interfacial adhesion between fiber and matrix,which was not conducive to the development of mechanical properties of UHTCC.

ultra-high toughness cementitious compositeswater to binder ratiopolyethylene fiber contentmechanical propertiesearly shrinkage propertiesmicrostructure

曾旭、蒋伟勤、冯庆革、罗祺、田月晖、程晓蝶、武丽云、冯靖航

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广西大学 资源环境与材料学院,广西 南宁 530004

柳州工学院 土木建筑工程学院,广西 柳州 545616

重庆交通大学 土木工程学院,重庆 400074

南宁学院 土木与建筑工程学院,广西 南宁 530200

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超高性能水泥基复合材料 水胶比 聚乙烯纤维掺量 力学性能 早期收缩性能 微观结构

国家自然科学基金广西壮族自治区高等学校中青年教师科研基础能力提升项目广西自然科学基金

521082692022KY16922018GXNSFBA050008

2024

10.3969/j.issn.1002-3550.2024.03.005

混凝土
中国建筑东北设计研究院有限公司

混凝土

CSTPCD北大核心
影响因子：0.844
ISSN：1002-3550
年,卷(期)：2024.(3)
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