Low-carbon UHPC with carbonated blast furnace slag: Impact of mineral composition, carbonation degree, and CaCO3 polymorphs

IF 10.8 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement & concrete composites Pub Date : 2025-03-11 DOI:10.1016/j.cemconcomp.2025.106039

Hammad Ahmed Shah , Jiang Du , Weina Meng

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引用次数: 0

Abstract

As a common supplementary cementitious material (SCM), blast furnace slag (slag) is widely used in ultra-high-performance concrete (UHPC) to enhance properties and reduce its carbon footprint. Slag can be carbonated before use to further improve resilience and sustainability of UHPC. However, using raw/carbonated slag and other SCMs in UHPC presents challenges: (1) Variations in supply and production cause fluctuations in chemical, mineral, and physical properties, resulting in significant variability in carbonated slag and UHPC properties; (2) The utilization rate of slag is limited due to its low reactivity; and (3) How variations in slag's mineral composition impact carbonation kinetics and UHPC properties remains unclear. This study addresses these fundamental limitations through comprehensive research.

Four slags with unique mineral compositions were studied, replacing 40 % and 60 % of cement in UHPC. Both raw and carbonated slags were used to assess the effects of mineral composition, carbonation degree, and CaCO₃ polymorphs on UHPC properties. The findings revealed three insights: (1) slags with similar particle size and chemical composition showed varying impacts on UHPC properties, emphasizing mineral composition's role; (2) mineral composition significantly affects carbonation degree and CaCO₃ polymorph formation; and (3) slag carbonation notably enhances UHPC properties, potentially boosting slag utilization. Slags rich in alite, belite, and anhydrite show higher carbonation, while those with åkermanite and merwinite promote aragonite due to Mg²⁺ ions. Higher alite, belite, diopside, and gehlenite in raw slag increase UHPC compressive strength. Carbonated slag in UHPC increased compressive strength by 20 %, flexural strength by 30 %, and toughness by 45 %.

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碳化高炉渣低碳UHPC：矿物组成、碳化程度和CaCO3多晶型的影响

高炉矿渣作为一种常用的补充胶凝材料，被广泛应用于超高性能混凝土（UHPC）中，以提高其性能并减少其碳足迹。使用前可对炉渣进行碳化处理，进一步提高UHPC的回弹性和可持续性。然而，在UHPC中使用原料/碳化渣和其他SCMs存在挑战：(1)供应和生产的变化会导致化学、矿物和物理性质的波动，从而导致碳化渣和UHPC性质的显著变化；(2)渣的反应性低，限制了其利用率；(3)矿渣矿物组成的变化对碳化动力学和UHPC性能的影响尚不清楚。本研究通过全面的研究来解决这些根本性的局限性。研究了四种矿物组成独特的矿渣，分别替代了UHPC中40%和60%的水泥。利用原渣和碳化渣来评估矿物组成、碳化程度和CaCO3多态性对UHPC性能的影响。结果表明：(1)相似粒度和化学成分的炉渣对UHPC性能的影响不同，强调矿物成分的作用；(2)矿物组成显著影响碳酸化程度和CaCO3多晶的形成；(3)炉渣碳化显著提高了UHPC性能，有望提高炉渣的利用率。富含阿利石、白石和硬石膏的矿渣碳酸化程度较高，而含有角石和丝光石的矿渣由于Mg2+离子的作用促进文石形成。原渣中高含量的阿利石、白橄榄石、透辉石和辉长石提高了UHPC的抗压强度。碳化渣使UHPC的抗压强度提高20%，抗折强度提高30%，韧性提高45%。

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来源期刊

Cement & concrete composites 工程技术-材料科学：复合

CiteScore

18.70

自引率

11.40%

发文量

459

审稿时长

65 days

期刊介绍： Cement & concrete composites focuses on advancements in cement-concrete composite technology and the production, use, and performance of cement-based construction materials. It covers a wide range of materials, including fiber-reinforced composites, polymer composites, ferrocement, and those incorporating special aggregates or waste materials. Major themes include microstructure, material properties, testing, durability, mechanics, modeling, design, fabrication, and practical applications. The journal welcomes papers on structural behavior, field studies, repair and maintenance, serviceability, and sustainability. It aims to enhance understanding, provide a platform for unconventional materials, promote low-cost energy-saving materials, and bridge the gap between materials science, engineering, and construction. Special issues on emerging topics are also published to encourage collaboration between materials scientists, engineers, designers, and fabricators.