Bond behaviour between steel fibre and cement mortar exposed to elevated temperature

IF 1.8 4区工程技术 Q3 CONSTRUCTION & BUILDING TECHNOLOGY

Magazine of Concrete Research Pub Date : 2024-04-18 DOI:10.1680/jmacr.23.00210

Yuyang Pang, Qun Tang, Zhenqi Li, Danying Gao, Lin Yang, Dongxu Liu, Dawei Li

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Abstract

In order to accurately evaluate the deterioration of the mechanical properties of steel fibre reinforced concrete (SFRC) after exposure to elevated temperature, it is particularly important to study the bonding properties between steel fibre and concrete matrix. In this paper, four types of steel fibre and five types of cement mortars with different strengths were selected to investigate the bond behaviour of the steel fibre-mortar interface after exposure to elevated temperature. The results showed that the compressive strength and flexural strength of each mortar decreased significantly after elevated temperature treatment, and the attenuation degree of flexural strength was greater than that of the compressive strength. In addition, the ultimate pull-out load of specimen with the straight steel fibre gradually decreased with the increase of temperature. However, the ultimate pull-out load of specimen with the end-hooked steel fibre had no significant change between 20°C and 400°C. When the temperature exceeded 400°C, the ultimate pull-out load gradually decreased with the increase of elevated temperature. Subsequently, the damage mechanism of the interface between steel fibre and mortar matrix under condition of elevated temperature was analyzed by testing the interfacial microstructure and phase change of cement paste. Finally, the calculation formula of the ultimate bond strength and temperature was established.

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钢纤维与水泥砂浆在高温下的粘接性能

为了准确评估钢纤维增强混凝土（SFRC）暴露于高温后的机械性能劣化情况，研究钢纤维与混凝土基体之间的粘结性能尤为重要。本文选择了四种钢纤维和五种不同强度的水泥砂浆，研究钢纤维-水泥砂浆界面在暴露于高温后的粘结行为。结果表明，经高温处理后，每种砂浆的抗压强度和抗折强度都明显下降，且抗折强度的衰减程度大于抗压强度。此外，直钢纤维试样的极限拉拔荷载随温度升高而逐渐减小。然而，在 20°C 至 400°C 之间，带有末端钩状钢纤维的试样的极限拉拔载荷没有明显变化。当温度超过 400°C 时，极限拉拔载荷随温度升高而逐渐减小。随后，通过测试界面微观结构和水泥浆相变，分析了高温条件下钢纤维与砂浆基体界面的破坏机理。最后，建立了极限粘结强度与温度的计算公式。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Magazine of Concrete Research 工程技术-材料科学：综合

CiteScore

4.60

自引率

11.10%

发文量

102

审稿时长

5 months

期刊介绍： For concrete and other cementitious derivatives to be developed further, we need to understand the use of alternative hydraulically active materials used in combination with plain Portland Cement, sustainability and durability issues. Both fundamental and best practice issues need to be addressed. Magazine of Concrete Research covers every aspect of concrete manufacture and behaviour from performance and evaluation of constituent materials to mix design, testing, durability, structural analysis and composite construction.