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.

民用基础设施的使用寿命主要受到混凝土（最广泛使用的建筑材料）的劣化机制的限制，特别是，随着人们对水泥材料耐久性的兴趣日益浓厚，酸侵蚀会降解混凝土结构中的水泥材料。迄今为止，在试图阐明酸侵蚀机制的流行实验和计算方法中尚未从根本上考虑这一点，仅使用均质数值模型。忽略一系列尺度上发生的具体异质性描述，需要一种将化学（即反应热力学和动力学）以及多孔介质中混凝土组分的多尺度分布现象结合起来的基本方法。目前才刚刚开始探索，但很可能迅速成为多个科学领域的主要焦点。ExpeRTa 的主要目标是研究和阐明因酸侵蚀而导致混凝土降解的基本机制，重点是O1) 使用 Hymostruc 3D 虚拟微观结构进行孔隙尺度数值模拟，并实施针对酸侵蚀的反应输运降解模型；反应输运模型的升级；O3) 关于材料设计和攻击参数的浆料、砂浆和混凝土降解的实验程序；O4) 通过实验获得的数值模型的多尺度分析、校准和验证；计划的实验方法包括：μ-XRF、SAXS、纳米压痕、MIP、气体吸附、热分析、XRD、光学显微镜、EDX 的 ESEM 和 3D-μ-CT 成像。实验活动的设计方式是：结果可用于校准和验证所开发的数值模型对混凝土配合比设计（粘合剂中的水灰比和 Ca/Si 比、骨料类型以及用量）的影响。将研究边界（攻击）条件的酸类型和参数。在这次协同合作中，达姆施塔特大学团队作为反应输运计算的混凝土耐久性建模专家，将与材料专家 KIT 团队密切合作。这种独特的基本建模方法的结果与基于既定科学原理和加速耐久性测试的已知校准的外推相结合，将显着提高混凝土结构使用寿命的准确性。预测。