Shear behaviour and pore characteristics of biochar amended recycled concrete aggregates subjected to freeze-thaw cycles

IF 3.8 2区工程技术 Q1 ENGINEERING, CIVIL

Cold Regions Science and Technology Pub Date : 2025-09-17 DOI:10.1016/j.coldregions.2025.104692

Yongsheng Yao , Lei Wang , Haowen Guo , Jue Li , Lihao Liu

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引用次数: 0

Abstract

Using recycled concrete aggregates (RCAs) as road base materials provides environmental and economic benefits in preserving natural resources and reducing solid waste. Biochar derived from the pyrolysis of agricultural waste has been proven to serve as a sustainable and eco-friendly amendment, used to mitigate the environmental risks associated with construction waste. This study conducts a series of drained triaxial tests to assess the effects of biochar on the shear behaviour of RCAs under freeze-thaw (F-T) cycles. Three biochar contents are considered in this study (0 %, 5 % and 10 % (g/g)). According to the results, biochar helps to increase the peak shear stress of RCA by up to 60 % without F-T cycles. However, due to the pore structure evolution, the shear stress for biochar-amended cases is lower than the bare RCA after 5 F-T cycles. Adding biochar increases the critical state friction angle by 20 %. Nevertheless, biochar has an insignificant influence on the critical state shear strength under low confining stress regardless of F-T cycles. Moreover, the differences in the shear strength behaviour between specimens with 5 % and 10 % biochar are insignificant. The amendment of 5 % biochar is thus suggested as it can substantially enhance the mechanical behaviours of RCA during shear.

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冻融循环下生物炭改性再生混凝土骨料的剪切行为和孔隙特性

使用再生混凝土集料作为道路基层材料，在保护自然资源和减少固体废物方面具有环境和经济效益。从农业废弃物热解中提取的生物炭已被证明是一种可持续的、环保的修正物，用于减轻与建筑垃圾相关的环境风险。本研究进行了一系列排水三轴试验，以评估生物炭对冻融循环下RCAs剪切行为的影响。本研究考虑了三种生物炭含量（0%、5%和10% (g/g)）。结果表明，在没有F-T循环的情况下，生物炭有助于将RCA的峰值剪切应力提高60%。然而，由于孔隙结构的演化，经过5次F-T循环后，生物炭改性后的剪切应力低于裸RCA。添加生物炭可使临界状态摩擦角提高20%。在低围应力条件下，生物炭对临界状态剪切强度的影响不显著。此外，添加5%和10%生物炭的试件的抗剪强度特性差异不显著。因此，建议添加5%的生物炭，因为它可以大大提高RCA在剪切过程中的力学性能。

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

Cold Regions Science and Technology 工程技术-地球科学综合

CiteScore

7.40

自引率

12.20%

发文量

209

审稿时长

4.9 months

期刊介绍： Cold Regions Science and Technology is an international journal dealing with the science and technical problems of cold environments in both the polar regions and more temperate locations. It includes fundamental aspects of cryospheric sciences which have applications for cold regions problems as well as engineering topics which relate to the cryosphere. Emphasis is given to applied science with broad coverage of the physical and mechanical aspects of ice (including glaciers and sea ice), snow and snow avalanches, ice-water systems, ice-bonded soils and permafrost. Relevant aspects of Earth science, materials science, offshore and river ice engineering are also of primary interest. These include icing of ships and structures as well as trafficability in cold environments. Technological advances for cold regions in research, development, and engineering practice are relevant to the journal. Theoretical papers must include a detailed discussion of the potential application of the theory to address cold regions problems. The journal serves a wide range of specialists, providing a medium for interdisciplinary communication and a convenient source of reference.