| 摘要: |
| 利用自制加压装置对不同强度等级和尺寸规格的10个钢管混凝土试件进行压力养护，研究了养护压力和持续时间对试件轴压强度、应变和破坏特征的影响，分析了水化产物发育、孔结构和微裂纹结构的发展情况.结果表明：压力养护促使体系更加致密，能够抑制微裂纹形成和发展；水化产物结晶发育良好，可填充孔隙结构，提高混凝土自身强度；当压力传导至钢管时使其产生环向拉伸应变，核心混凝土终凝后，钢管收缩对其产生预压应力，两者协同增强，从而提高了试件的轴向承载力. |
| 关键词: 压力养护 钢管混凝土 力学性能 微观结构 |
| DOI：10.3969/j.issn.1007-9629.2023.10.007 |
| 分类号:TU398+.9 |
| 基金项目:中建股份科技研发课题（CSCEC-2021-Z-16） |
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| Mechanical Properties and Microstructure of Concrete Filled Steel Tube Hardening under Pressure Curing |
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WANG Kaiqiang1,2, SUN Qing1,2, DONG Yaowu1,2, LIN Qi1,2, YANG Hui1,2
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1.China Construction Third Bureau Group Co.， Ltd.， Wuhan 430070， China;2.China Construction Institute of Advanced Technology， Wuhan 430070， China
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| Abstract: |
| 10 concrete filled steel tube（CFST） specimens with different strength grades and sizes were cured under pressure by self-designed hydraulic device. The effects of curing pressure and its duration on uniaxial compressive strength， stress-strain variation and failure characteristic of CFST specimens were studied. Microscopic test methods were used to study the development and formation of pore structure and hydration products. The results show that the particles in the mixture are squeezed close to each other under pressure curing， and the formation and development of microcracks are inhibited， which lead to the higher compactness of core concrete. Moreover， the crystallization process of hydration products are promoted， and the pore structure can be fully filled by the hydration products， which improves the strength of core concrete. In addition， the pressure causes the circumferential tensile strain of steel tube， which provides pre-compressive stress on core concrete after final setting time. Therefore， the uniaxial compressive properties of the CFST are improved. |
| Key words: pressure curing concrete filled steel tube（CFST） mechanical property microstructure |
