Pure Mode Ⅱ Shear Fracture Performance of Recycled Concrete after High Temperature

doi:10.16552/j.cnki.issn1001-1625.2025.0446

Abstract

Abstract: The shear fracture characteristics of recycled concrete under high temperatures is one of the key factors to evaluate structural safety in fires. This study prepared C30 concrete specimens with different replacement ratios of recycled coarse aggregate (0%, 50%, 100%, mass fraction). These specimens were subjected to high temperature treatments at 25~600 ℃. Shear tests were conducted using novel pure mode Ⅱ fracture specimens to systematically analyze the effects of high temperature damage and recycled aggregate on the shear fracture properties of recycled concrete. The results indicate that elevated temperature significantly reduces the fracture toughness. The fracture energy reaches its peak at 400 ℃. An increased replacement ratio of recycled coarse aggregate exacerbates the performance degradation. When the replacement ratio is 100%, the fracture energy of specimens at room temperature and 600 ℃ decreases by 20.15% and 12.69%, respectively, compared to natural concrete. The load-displacement curves exhibit more pronounced brittle failure characteristics with increasing temperature and replacement ratio. Mechanistic analysis shows that high temperature causes microcrack propagation in the interfacial transition zone (ITZ) between the cement matrix and aggregate, along with hydrate decomposition. The surface defects and high water absorption of recycled aggregate further weaken the performance of interfacial bond, promoting shear crack propagation along these weak zones. The research reveals the degradation patterns of fracture parameters under the synergistic effect of high temperature and recycled aggregate, and establishes a synergistic degradation mechanism between fracture energy and shear strength. It provides a theoretical basis for the safety assessment of recycled concrete structures after fire exposure.

Key words: recycled concrete, high-temperature damage, mode Ⅱ fracture, fracture parameter, shear strength

CLC Number:

TU528

GAO Litang, MA Jiatao, TIAN Yupeng, WANG Haichao, DU Yanxin. Pure Mode Ⅱ Shear Fracture Performance of Recycled Concrete after High Temperature[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2025, 44(10): 3587-3596.

References

[1] 白卫峰, 李思蕾, 管俊峰, 等. 再生混凝土的单轴压缩动态力学性能[J]. 建筑材料学报, 2022, 25(5): 498-508.
BAI W F, LI S L, GUAN J F, et al. Dynamic mechanical properties of recycled concrete under uniaxial compression[J]. Journal of Building Materials, 2022, 25(5): 498-508 (in Chinese).
[2] FEMANDS B, CARRE H, GABORIEAU C, at al. Thermomechanical properties and microstructure of concrete made with recycled concrete aggregates after exposure to high temperatures[J]. Fire and Materials, 2024, 49(1): 59-75.
[3] MEFTAH H, ARABI N. Effects of elevated temperatures' exposure on the properties of concrete incorporating recycled concrete aggregates[J]. Construction and Building Materials, 2024, 411: 134612.
[4] TRIVEDI S S, SARANGI D, DAS B B, et al. Influence of multi-stage processing and mechano-chemical treatments on the hydration and microstructure properties of recycled aggregate concrete[J]. Construction and Building Materials, 2023, 409: 133993.
[5] LUO L, JIA M M, WANG H W, et al. Experimental evaluation and microscopic analysis of the sustainable ultra-high-performance concrete after exposure to high temperatures[J]. Structural Concrete, 2025, 26(3): 2787-2815.
[6] CHEN Z P, CHEN J J, NING F, et al. Residual properties of recycled concrete after exposure to high temperatures[J]. Magazine of Concrete Research, 2019, 71(15): 781-793.
[7] ZHANG M M, ZHU L H, GAO S, et al. Mechanical properties, microstructure, and environmental assessment of recycled concrete from aggregate after fire[J]. Construction and Building Materials, 2024, 425: 136074.
[8] CHEN W, YANG H F. Fracture performance of concrete incorporating different levels of recycled coarse aggregate[J]. Structural Concrete, 2021, 22(supplement 1): 48-57.
[9] XIAO J Z, TANG Y X, CEHN H N, et al. Effects of recycled aggregate combinations and recycled powder contents on fracture behavior of fully recycled aggregate concrete[J]. Journal of Cleaner Production, 2022, 36(15): 132895.
[10] ADESSINA A, BEN FRAJ A, BARTHÉLÉMY J F, et al. Experimental and micromechanical investigation on the mechanical and durability properties of recycled aggregates concrete[J]. Cement and Concrete Research, 2019, 126: 105900.
[11] FANG G H, CHEN J T, DONG B Q, et al. Microstructure and micromechanical properties of interfacial transition zone in green recycled aggregate concrete[J]. Journal of Building Engineering, 2023, 66: 105860.
[12] CHEN W, PENG L X, YANG H F, et al. Residual fracture energy of natural and recycled aggregate concrete after exposure to high temperatures[J]. Structural Concrete, 2023, 24(2): 1879-1892.
[13] CHEN W, PENG L X, YANG H F. Fracture behaviors of concrete incorporating different levels of recycled coarse aggregate after exposure to elevated temperatures[J]. Journal of Building Engineering, 2021, 35: 02040.
[14] VIEIRA J P B, CORREIA J R, DE BRITO J. Post-fire residual mechanical properties of concrete made with recycled concrete coarse aggregates[J]. Cement and Concrete Research, 2011, 41(5): 533-541.
[15] 陆洲导, 俞可权, 苏磊, 等. 高温后混凝土断裂性能研究[J]. 建筑材料学报, 2012, 15(6): 836-840+846.
LU Z D, YU K Q, SU L, et al. Residual fracture behaviors of concrete subjected to elevated temperatures[J]. Journal of Building Materials, 2012, 15(6): 836-840+846 (in Chinese).
[16] WANG J, GUO Z X, ZHANG P, et al. Fracture properties of rubberized concrete under different temperature and humidity conditions based on digital image correlation technique[J]. Journal of Cleaner Production, 2020, 276: 124106.
[17] 杭振园, 喻莹. 混凝土-环氧砂浆界面Ⅰ-Ⅱ型断裂性能试验研究[J]. 工业建筑, 2023, 53(2): 29-36.
HANG Z Y, YU Y. Experimental study on the fracture properties of type Ⅰ-Ⅱ at the interface between concrete and epoxy mortar[J]. Industrial Buildings, 2023, 53(2): 29-36 (in Chinese).
[18] 王海超, 高义龙, 安雪晖, 等. 自密实堆石混凝土Ⅰ-Ⅱ复合型断裂性能[J]. 混凝土, 2013(7): 7-10.
WANG H C, GAO Y L, AN X H, et al. Experimental study on Ⅰ-Ⅱ mixed mode fracture performance and influence of crack-depth of self-compacting rock-filled concrete[J]. Concrete, 2013(7): 7-10 (in Chinese).
[19] MAHMOUD A, ABDEL K A. Comprehensive investigation of rock fracture behaviour in clay-rich rocks under the effect of temperature: experimental study under three loading modes (Ⅰ, Ⅰ/Ⅱ, Ⅱ)[J]. Engineering Fracture Mechanics, 2022, 276.
[20] YU J J, LI G D, REN Z Y, et al. Mixed-mode Ⅰ-Ⅱ mesoscale fracture behavior of concrete determined by the realistic aggregate numerical model[J]. Construction and Building Materials, 2019, 226: 802-817.
[21] 中华人民共和国住房和城乡建设部. 普通混凝土配合比设计规程: JGJ 55—2011[S]. 北京: 中国建筑工业出版社, 2011.
Ministry of Housing and Urban-Rural Development of the People's Republic of China. Specifications for mix design of ordinary concrete: JGJ 55—2011[S]. Beijing: China Construction Industry Press, 2011 (in Chinese).
[22] 中华人民共和国国家质量监督检验检疫总局, 中国国家标准化管理委员会. 混凝土用再生粗骨料: GB/T 25177—2010[S]. 北京: 中国标准出版社, 2011.
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China, National Standardization Administration of China. Recycled coarse aggregate for concrete: GB/T 25177—2010[S]. Beijing: China Standards Publishing House, 2011 (in Chinese).
[23] 王海超. 一种新型直剪式混凝土断裂性能测试试件及测试方法: CN116698572A[P]. 2025.
WANG H C. A new type of direct shear concrete fracture performance test specimen and test method: CN116698572A[P]. 2025 (in Chinese).
[24] MAANSER A, BENOUIS A, FERHOUNE N. Effect of high temperature on strength and mass loss of admixtured concretes[J]. Construction and Building Materials, 2018, 166(30): 916-921.
[25] IVANKA N, IVANA K, IVICA G. The effect of high temperatures on the mechanical properties of concrete made with different types of aggregates[J]. Fire Safety Journal, 2011, 46: 425-430.
[26] 胡岳峰, 王晓刚, 李基恒, 等. 再生混凝土火灾后残余力学性能研究[J]. 西部交通科技, 2024(9): 4-8.
HU Y F, WANG X G, LI J H, et al. Study on residual mechanical properties of recycled concrete after fire[J]. Western China Communications Science & Technology, 2024(9): 4-8 (in Chinese).
[27] YU K Q, YU J T, LU Z D, et al. Fracture properties of high-strength/high-performance concrete (HSC/HPC) exposed to high temperature[J]. Materials and Structures, 2016, 49(11): 4517-4532.
[28] LIU X, YUAN Y M, Ye G, et al. Investigation on the mechanism of explosive spalling of high performance concrete at elevated temperatures[J]. China Civil Engineering Journal, 2008, 41(6): 61-68.
[29] XU S L, REINHARDT H W, GAPPOEV M. Mode Ⅱ fracture testing method for highly orthotropic materials like wood[J]. International Journal of Fracture, 1996, 75(3): 185-214.
[30] TADE H, PARIS P C, IRWIN G R. The stress analysis of cracks handbook[M]. Hellertown Pa: Del Research Corp, 1973.
[31] YU Z P, ZHAN X F, JIAO M X, et al. Study on the fracture mechanical properties of high performance concrete (HPC) with rapid cooling after high temperature[J]. Construction and Building Materials, 2024, 422: 135718.