COLLAbORATE: Performance of alkali-activated slag concrete as cover to rebar against penetration of chloride

合作：碱激活矿渣混凝土作为钢筋覆盖层防止氯化物渗透的性能

• 批准号: EP/X022587/1
• 负责人: Zhenming Li
• 金额: $ 26万
• 依托单位: University of Sheffield
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FX022587%2F1
• 关键词: COLLAbORATE; Performance; alkali; activated; slag

This project is aimed to evaluate the performanCe Of alkaLi-activated sLag concrete As cOver to Rebar Against peneTration of chloridE (COLLAbORATE). Alkali-activated materials (AAMs) have emerged as eco-friendly alternatives to OPC due to lower embodied energy and CO2 emission. Reinforced concrete structures using alkali-activated slag (AAS) as the binder have been appearing in different regions of the world. The penetration of chloride is the main reason for the corrosion of reinforcing steel in cold-winter or marine climates. However, the performance of AAS as protection of rebar against chloride penetration has not been well understood. The existing knowledge on chloride binding and transport in plain AAS investigated in lab conditions does not allow a realistic estimation of the service life of reinforced AAS concrete in practice, where restraint by rebar, drying and contact with water can all make substantial differences. COLLAbORATE will first evaluate the cracking profile of AAS concrete cover due to the restrained autogenous and drying shrinkage by rebar. In-situ nano X-ray computed tomography combined with Digital Volume Correlation will be utilized to monitor the cracking development. The products and microstructure modification due to leaching caused by contact with water will then be characterized by advanced techniques. The effects of cracking and leaching on water convection, chloride binding and chloride transport will be quantified. These results will be used as inputs to build chloride transport model. Non-destructive techniques such as wireless iCOR will be used to inspect the initiation of corrosion as validation of the model. Service life of the reinforced AAS concrete can be then predicted. This project will lay the knowledge base to establish design methods of reinforced AAS concrete and contribute to standardisation for related concrete structures, which is of great significance for a wider application of sustainable AAMs.

本课题旨在评价碱矿渣混凝土对钢筋抗氯离子侵蚀性能的影响。碱活化材料（AAMs）由于具有较低的内含能量和CO2排放，已成为OPC的生态友好型替代品。使用碱矿渣（AAS）作为粘结剂的钢筋混凝土结构已在世界不同地区出现。在寒冷的冬季或海洋气候条件下，氯离子的渗透是钢筋腐蚀的主要原因。然而，AAS作为保护钢筋免受氯化物渗透的性能还没有得到很好的理解。在实验室条件下研究的普通AAS中氯离子结合和运输的现有知识不允许实际估计钢筋AAS混凝土的使用寿命，其中钢筋的约束，干燥和与水接触都可以产生实质性的差异。COLLABORATE将首先评估AAS混凝土保护层的裂缝轮廓，这是由于钢筋限制了自生和干燥收缩。原位纳米X射线计算机断层扫描结合数字体积相关将被用来监测裂缝的发展。然后，将通过先进的技术来表征由于与水接触而导致的浸出而导致的产品和微观结构改性。将量化开裂和沥滤对水对流、氯离子结合和氯离子迁移的影响。这些结果将被用作输入建立氯离子传输模型。将使用无线iCOR等非破坏性技术来检查腐蚀的开始，作为模型的验证。由此可以预测配筋AAS混凝土的使用寿命。本项目将为AAS混凝土设计方法的建立奠定基础，并为相关混凝土结构的标准化做出贡献，这对AAM的广泛应用具有重要意义。