Experimentally supported multi-scale Reactive Transport modeling of cementitious materials under Acid attack (ExpeRTa)

实验支持的酸侵蚀下胶结材料的多尺度反应输运模型 (ExpeRTa)

• 批准号: 426807554
• 负责人: Professor Dr.-Ing. Frank Dehn
• 金额: --
• 依托单位: Institut für Werkstoffe im Bauwesen
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/426807554?language=en
• 关键词: Experimentally; supported; multi; scale; Reactive

Service-life of civil infrastructure is dominantly limited by deterioration mechanisms of concrete, the most widely used construction material. Particularly, acid attack is degrading cementitious materials in concrete structures. With increasing interest in the durability of cementitious materials, a better understanding of the underlying reactive-transport phenomena for concrete material in multi-scale is essential. Hitherto, this is not yet fundamentally considered in the prevailing experimental and computational approaches trying to elucidate the acid attack mechanisms. Only homogenized numerical models have been used so far, neglecting concrete heterogeneity descriptions occurring across a range of scales. A fundamental approach is needed that couples the chemistry, i.e. reaction thermodynamics and kinetics as well as transport phenomena with a multi-scale distribution of concrete components. Multiscale reactive-transport phenomena in porous media in general just starting to be explored these days, but are likely to become a primary focus in several scientific fields rapidly.Key objectives of ExpeRTa are to investigate and elucidate the fundamental mechanisms that cause concrete degradation due to acid attack with an emphasis on heterogeneity effects in the reactive-transport characteristics across a range of scales. This includes: O1) pore-scale numerical modelling using Hymostruc 3D virtual microstructures and implementation of the reactive transport degradation model for acid attack; O2) Meso-scale numerical modelling and upscaling of the reactive transport model; O3) An experimental program on paste, mortar and concrete degradation regarding materials design and attack parameters; O4) Multiscale analysis, calibration and validation of the numerical models with the obtained experimental results.Planned experimental methods comprise: µ-XRF, SAXS, Nanoindentation, MIP, gas sorption, thermal analysis, XRD, light microscopy, ESEM with EDX, and 3D-µ-CT imaging. The experimental activities are designed in such a way that the results can be used to calibrate and validate the developed numerical models. The influence of concrete mix design (water-to-cement-ratio and Ca/Si -ratio in binder, aggregate type as well as amount and size), acid type and parameters of boundary (attack) conditions will be investigated. In this synergetic cooperation, the Darmstadt University team, as concrete durability modelling experts for reactive transport computations, will cooperate intensively with the KIT team, who are experts for material testing and analysis and experimental investigation of acid attack on cementitious materials. The results of this unique fundamental modelling approach combined with extrapolations based on established scientific principles and known calibrations from accelerated durability tests, will significantly enhance the accuracy of the concrete structures service-life predictions.

民用基础设施的服务与人生受到最广泛使用的建筑材料的定义机制的主要限制。特别是，酸的攻击正在降解混凝土结构中的水泥材料。随着对水泥材料持久性的兴趣日益增加，对多尺度中混凝土材料的潜在反应性传输现象的更好理解至关重要。迄今为止，在现行的实验和计算方法中尚未考虑这尚未考虑阐明酸攻击机制。到目前为止，仅使用均质的数值模型，忽略了在一系列尺度上发生的具体异质性描述。需要一种基本方法，即将化学，即反应热力学和动力学以及具有混凝土成分的多尺度分布的转运现象。一般来说，这些天多孔媒体中的多尺度反应性传播现象通常刚刚开始探索，但很可能成为几个科学领域的主要重点。专家的关键目标是调查和阐明导致由于反应性和跨性别特征的异质性影响而导致酸攻击对异质性影响的基本机制，从而导致酸性攻击对酸性攻击的影响。这包括：O1）使用Hymostruc 3D虚拟微结构的孔尺度数值建模以及用于酸攻击的反应性传输降解模型的实现； O2）反应性传输模型的中尺度数值建模和升级； O3）关于材料设计和攻击参数的糊，砂浆和具体定义的实验计划； O4）通过获得的实验结果对数值模型的多尺度分析，校准和验证。计划完成：µ-XRF，SAX，纳米凹痕，MIP，MIP，气体吸附，热分析，XRD，XRD，光学显微镜，EDX和3D-µ-CT的ESEM。实验活动的设计方式可以用于校准和验证开发的数值模型。混凝土混合物设计（粘合剂中的水污等利率和Ca/si-ratio，骨料类型以及量和大小），边界（攻击）条件的酸性和参数的影响。在这一协同合作中，达姆施塔特大学团队作为反应性运输计算的具体耐用性建模专家，将与Kit团队进行密切合作，Kit团队是材料测试和分析的专家，并对酸性材料的酸攻击进行了实验投资。这种独特的基本建模方法的结果结合了基于既定的科学原理和加速耐用性测试的已知校准的外推，将显着提高混凝土结构服务寿命预测的准确性。