Skim milk powder as a urease stabilizer for efficient EICP treatment of recycled concrete aggregates

IF 3.9 3区工程技术 Q2 CONSTRUCTION & BUILDING TECHNOLOGY

Materials and Structures Pub Date : 2026-10-07 DOI:10.1617/s11527-026-03290-3

Rui Zhang, Aowei Ma, Dezhi Xie, Jianyun Wang

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引用次数: 0

Abstract

The use of recycled concrete aggregate (RCA) in concrete is constrained by porous adhered mortar and defects inherited from demolition and crushing. This study evaluated skim milk powder as a stabilizing additive for enzyme-induced carbonate precipitation (EICP) treatment of RCA. The effects of milk-powder addition sequence and concentration (0–8 g/L) were examined in triplicate by monitoring pH and dissolved Ca²⁺, urea decomposition, dry mass gain, mass loss after a fixed ultrasonic-detachment test, water absorption, and deposit morphology and elemental composition by SEM/EDS. Adding milk powder after urease (U-M) or premixing milk powder with urease (UM) produced final Ca²⁺ utilization values of 87.2% and 88.4%, respectively. A dosage of 4 g/L was selected as a practical working concentration because higher dosages provided no clear additional benefit across the measured responses. Under the tested conditions, the largest reduction in RCA water absorption was 41.4%, compared with 17.1% for urease without milk powder. SEM/EDS observations were consistent with a finer and denser organic-mineral deposit in the milk-containing treatment. These results demonstrate the effectiveness of milk-powder-assisted EICP for improving pore-related RCA properties.

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脱脂奶粉作为脲酶稳定剂用于高效EICP处理再生混凝土集料

再生混凝土骨料（RCA）在混凝土中的使用受到多孔粘结砂浆和拆除和破碎遗留缺陷的限制。本研究评价了脱脂奶粉作为酶诱导碳酸盐沉淀（EICP）处理RCA的稳定添加剂。通过监测pH、溶解Ca2 +、尿素分解、干质量增加、固定超声分离后的质量损失、吸水率、SEM/EDS分析、沉积物形貌和元素组成，考察了添加顺序和浓度（0-8 g/L）对奶粉的影响。脲酶（U-M）后添加奶粉或将奶粉与脲酶（UM）预混后添加奶粉，Ca2 +的最终利用率分别为87.2%和88.4%。选择4 g/L的剂量作为实际工作浓度，因为更高的剂量在测量的反应中没有明显的额外益处。在测试条件下，尿素酶对RCA吸水率的降低幅度最大，为41.4%，而不加奶粉的脲酶对RCA吸水率的降低幅度为17.1%。扫描电镜/能谱分析表明，含乳处理的有机矿物沉积物更细、密度更大。这些结果证明了奶粉辅助EICP在改善孔隙相关RCA性能方面的有效性。

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

Materials and Structures 工程技术-材料科学：综合

CiteScore

6.40

自引率

7.90%

发文量

222

审稿时长

5.9 months

期刊介绍： Materials and Structures, the flagship publication of the International Union of Laboratories and Experts in Construction Materials, Systems and Structures (RILEM), provides a unique international and interdisciplinary forum for new research findings on the performance of construction materials. A leader in cutting-edge research, the journal is dedicated to the publication of high quality papers examining the fundamental properties of building materials, their characterization and processing techniques, modeling, standardization of test methods, and the application of research results in building and civil engineering. Materials and Structures also publishes comprehensive reports prepared by the RILEM’s technical committees.