Damage mechanism and mechanical properties of steel fiber reinforced self-compacting concrete under fire

被引：0

作者：

Lei, Mingfeng ^{[1
,2
]}

Xiao, Fenglong ^{[1
]}

Zhang, Hu ^{[1
]}

Liu, Linghui ^{[1
]}

Zha, Xicao ^{[1
]}

Yang, Zihan ^{[3
]}

机构：

[1] School of Civil Engineering, Central South University, Changsha

[2] Key Laboratory of Engineering Structures of Heavy Haul, Changsha

[3] China Construction Fifth Engineering Bureau Co., Ltd, Changsha

来源：

Journal of Railway Science and Engineering | 2024年 / 21卷 / 10期

关键词：

compressive strength; constitutive equations; damage mechanism; high temperature in fire; steel fiber reinforced self-compacting concrete;

D O I：

10.19713/j.cnki.43-1423/u.T20232125

中图分类号：

学科分类号：

摘要：

Steel fiber reinforced self-compacting concrete (SFRSCC) stands out as an exemplary high-temperature resistant building material, effectively augmenting concrete properties while ensuring structural reliability. This study investigated the damage mechanisms and variations in mechanical properties of SFRSCC under high-temperature fire conditions to explore its behavior. Diverse SFRSCC specimens, featuring distinct steel fiber ratios, were meticulously prepared. Subsequently, ultrasonic testing, scanning electron microscopy (SEM) analysis, and axial compressive strength tests were conducted on these specimens exposed to temperatures reaching 800 ℃. Damage extent, microscopic change characteristics, and relative elastic modulus were evaluated to scrutinize high-temperature damage and stress-strain behavior. The findings reveal that the high-temperature damage mechanism of SFRSCC involves the evaporation of water molecules, decomposition of hydration products, material degradation, and interfacial thermal damage resulting from differential thermal expansion rates of distinct materials. Under high-temperature exposure, internal damage occurs in SFRSCC specimens, leading to a swift reduction in axial compressive strength, and elastic modulus with increasing temperature. At 800 ℃, the maximum reduction in axial compressive strength for the three specimen types is 11.3%, 66.68%, and 69.05%, accompanied by corresponding reductions in elastic modulus to 2.43 GPa, 2.39 GPa, and 2.99 GPa, respectively. The inclusion of hooked-end steel fibers significantly enhances concrete crack resistance, with the 1∶1 ratio of hooked-end to straight steel fibers exhibiting the most notable improvement in mechanical properties. By integrating temperature as a variable in the modified model by Guo Zhenghai, a compressive constitutive model for SFRSCC considering temperature effects was formulated. This model effectively predicts the stress-strain response of SFRSCC under high-temperature conditions. © 2024, Central South University Press. All rights reserved.

引用

页码：4201 / 4213

页数：12

共 24 条

[1]

BAO Jiuwen, ZHENG Rui, SUN Yanqun, Et al., A state-of-the-art review on high temperature resistance of lightweight aggregate high-strength concrete, Journal of Building Engineering, 69, (2023)

[2]

SHEN Haiyang, LIU Linghui, REN Lei, Study on mechanical properties of lightweight aggregate concrete under high temperature, Journal of Railway Science and Engineering, 19, 10, pp. 2976-2983, (2022)

[3]

MA Qianmin, GUO Rongxin, ZHAO Zhiman, Et al., Mechanical properties of concrete at high temperature—a review[J], Construction and Building Materials, 93, (2015)

[4]

HUA Weipan, LI Kaifeng, XIE Xiaojie, Experimental study on compressive strength and meso-damage of concrete under high temperature, Fire Science and Technology, 40, 9, (2021)

[5]

SADRMOMTAZI A, GASHTI S H, TAHMOURESI B., Residual strength and microstructure of fiber reinforced self-compacting concrete exposed to high temperatures, Construction and Building Materials, 230, (2020)

[6]

AHMAD S, RASUL M, ADEKUNLE S K, Et al., Mechanical properties of steel fiber-reinforced UHPC mixtures exposed to elevated temperature: effects of exposure duration and fiber content, Composites Part B: Engineering, 168, pp. 291-301, (2019)

[7]

GONG Chenjie, KANG Lei, LIU Linghui, Et al., A novel prediction model of packing density for single and hybrid steel fiber-aggregate mixtures, Powder Technology, 418, (2023)

[8]

PENG Shuai, LI Liang, WU Jun, Et al., Impact tests on dynamic compressivebehaviors of steel fiber reinforced concrete at elevated temperature, Journal of Vibration and Shock, 38, 22, (2019)

[9]

AGRA R R, SERAFINI R, DE FIGUEIREDO A D., Effect of high temperature on the mechanical properties of concrete reinforced with different fiber contents, Construction and Building Materials, 301, (2021)

[10]

ZHANG Junwei, YANG Zhe, LI Shijie, Et al., Investigation on mechanical property adjustment of multi-scale hybrid fiber-reinforced concrete, Case Studies in Construction Materials, 16, (2022)

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