超高强钢管混凝土研究综述

为了解超高强钢管混凝土(UCFST)的研究现状, 分析了钢管混凝土(CFST)中钢管与核心混凝土的材料强度发展历程, 根据这2种材料不同强度等级的组合, 梳理了1套简洁的CFST分类与缩写方法; 总结了UCFST的基本力学性能、收缩性能和界面粘结性能及其主要影响因素; 探讨了核心超高强混凝土(UHSC)的制备技术要求, 展望了UCFST未来的研究方向。分析结果表明: UCFST的提出与研究可分为UHSC和超高强钢材(UHSS)2条路径, 中国以前者为主, 对后者的研究较为滞后, 实际应用也较少; 已开展的UCFST基本力学性能试验研究, 体系仍不完善, 结构层次研究极少, 主要集中于构件层次但试验量偏少, 且以轴压短柱为主, 未见构件抗剪、抗扭及其余复合受力的研究; UCFST的研究以核心混凝土为UHSC的构件为主, 核心混凝土与钢管均为超高强的次之, 其他组合的较少; 钢管与核心混凝土的强度匹配研究才刚刚开始, 应继续深入, 重点研究合理匹配的UCFST; 核心UHSC自收缩大, 可能导致其与钢管脱粘, 应开展钢与UHSC法向黏结强度、UCFST构件收缩的研究; 应考虑核心UHSC材料的工作环境、施工条件及其对UCFST组合性能的影响, 核心UHSC材料以超高强度要求为主, 且具有低收缩(或微膨胀)、高流动性的特性, 不必强调耐久性; 制备核心UHSC材料时采用常温养护, 可少掺或不掺纤维。

Review on ultra-high strength concrete filled steel tubes

To understand the research status of the ultra-high strength concrete filled steel tube(UCFST), the strength development processes in steel tubes and core concrete in concrete filled steel tube(CFST) were analyzed. A set of concise CFST classification and abbreviation methods were put forward according to the combination of different strength grades of these two materials. The basic mechanical, shrinkage and interfacial bond properties of UCFST, and the main influencing factors were summarized. The technical requirements of core ultra-high strength concrete(UHSC) were discussed, and future research directions were proposed. Analysis result shows that UCFST can be fabricated and researched in two ways: UHSC and ultra-high strength steel(UHSS). The former is the main material used in China, while the latter lags behind in its practical application is less. Although the basic mechanical properties of the UCFST have been tested, the research is incomplete and research at the structural level is rarely conducted. Research on UCFST mainly focuses on the component level, but the amount of testing is relatively small, and analysis focuses on axially loaded stub columns. There is no research on UCFST components under shear, torsion, and residual composite forces. In terms of material combinations, research attention is mostly placed on UCFST within UHSC as core concrete, followed by UCFST within both UHSC and UHSS, with only a few studies addressing other combinations. The researche on strength matching between steel tubes and core concrete has just begun, and additional studies should be proposed, focusing on the UCFST with reasonable matching. Debonding occurs between the core UHSC and steel tube because of the high autogenous shrinkage of the former. Hence, additional experimental research on the shrinkage properties and normal interfacial bond strength of the UCFST should be conducted to understand the true interfacial state. The working environment, construction conditions, and influence on the UCFST composite performance of core UHSC materials should be considered. The core UHSC materials are mainly required for ultra-high strength, low shrinkage(or micro expansion), and high fluidity, but the durability not has to be emphasized. The UHSC mix may have fibers of low volume content or even no fibers.