摘要
针对工业污泥处置难及混凝土细骨料资源短缺的双重环境问题,提出将污泥制备成生物炭并作为替代细骨料应用于混凝土制备中。通过设置不同养护龄期(3 d、14 d、28 d),系统对比了普通混凝土与污泥生物炭混凝土的新拌浆体性能及硬化后的力学性能。研究结果表明:在流动性方面,由于生物炭的多孔结构及高吸水特性,B20组混凝土的坍落度较对照组有所降低,但仍满足施工要求。然而,在力学性能方面,污泥生物炭展现出显著的增强效果,B20组在各龄期的抗压强度与劈裂抗拉强度均优于普通混凝土,且后期强度增长尤为显著。结合XRD、FTIR、MIP及SEM微观表征发现,污泥生物炭显著促进了水泥水化进程,不仅增加了C-S-H/C-A-S-H凝胶的生成量,还将基体中有害大孔(>200 nm)转化为无害凝胶孔(<20 nm)。机理分析表明,生物炭通过微集料填充效应优化级配,利用内养护机制持续释水促进后期水化,并强化了骨料与浆体间的界面过渡区(ITZ),从而实现了混凝土宏观力学性能的全面提升。
To address the dual environmental challenges of difficult industrial sludge disposal and the shortage of fine aggregates for concrete,this study proposes the utilization of sludge-derived biochar as a substitute for fine aggregate in concrete preparation.By setting different curing ages(3 d,14 d,and 28 d),the fresh paste performance and hardened mechanical properties of ordinary concreteand sludge biochar concrete were systematically compared.The results indicate that regarding fluidity,the slump of the B20 group decreased compared to the control group due to the porous structure and high-water absorption characteristics of biochar,yet it still met construction requirements.However,in terms of mechanical properties,the sludge biochar demonstrated a significant enhancement effect.The compressive strength and splitting tensile strength of the B20 group at all curing ages were superior to those of the ordinary concrete,with particularly notable strength growth in the later stages.Combined with micro-structural characterizations using XRD,FTIR,MIP,and SEM,it was found that sludge biochar significantly promoted the cement hydration process.This not only increased the generation of C-S-H/C-A-S-H gel but also transformed harmful macro-pores(>200 nm)with in the matrix into harmless gel pores(<20 nm).Mechanism analysis reveals that the biochar optimized the particle gradation through the micro-aggregate filler effect,utilized the internal curing mechanism to continuously release water for promoting later-stage hydration,and strengthened the interfacial transition zone(ITZ)between the aggregate and the paste,thereby achieving a comprehensive improvement in the macroscopic mechanical properties of the concrete.
作者
姚彦欣
YAO Yanxin(Qingyuan Polytechnic,Qingyuan 511510,China)
出处
《混凝土》
北大核心
2026年第3期93-97,共5页
Concrete
基金
清远市社会科学规划课题(QYSK2022047)
清远职业技术学院课题(ZK16005)。
关键词
工业污泥
细骨料替代
流动性
抗压强度
微观机制
industrial sludge
fine aggregate replacement
fluidity
compressive strength
micro-mechanism
