Transport- und Löseprozesse im Gesteinskorn beim Ablauf einer AKR sowie Grundlagenuntersuchungen an AKR-Gelen

AKR 过程中岩石颗粒的传输和溶解过程以及 AKR 凝胶的基础研究

• 批准号: 202323396
• 负责人: Professor Dr.-Ing. Horst-Michael Ludwig
• 金额: --
• 依托单位: F. A. Finger-Institut für Baustoffkunde
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2011
• 资助国家: 德国
• 起止时间: 2010-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/202323396?language=en
• 关键词: Transport; und; seprozesse; im; Gesteinskorn

Within the research group 1498, sub-project 5 shall pursue the following 6 objectives: 1. It is to clarify, to what extent a mechanical pre-damage and cyclic loading can drive a critical amount of NaCl solu-tion into concrete. 2. The influence of processing-related micro cracks in aggregate grains shall be verified for another rock type. 3. By means of a nanoCT-system, the volume of ASR-gel formed in concrete prisms during the FIB cyclic climate storage test method shall be determined. The main ob-jective here is to elucidate, if there is a critical amount of gel that, if exceeded, will cause concrete deterioration as a function of the correspondingly measured expansions and the composition of the gels. This information is of particular interest for the modelling in sub-project 3. 4. Swelling pressures of synthetic ASR-gels will be measured as a function of their composition, water content and amount. With respect to its composition, besides the Ca-content it is the Na-content that is of particular interest here, because it is affected by an external supply of NaCl. Furthermore it shall be clarified, if the swelling ability of a gel is preserved below a certain content of water and what amount of gel is necessary to produce a deleterious pressure. In addition, the role of SiO2 dissolution for the swelling process will be investigated by measuring swelling pressures of rock powders subjected to artificial pore solutions. For a thermodynamic modelling, also solubility products and enthalpies of reaction will be determined for synthetic ASR-gels. The obtained data are of great importance for modelling the ASR damaging process within the scope of sub-project 3. 5. As a function of temperature and NaCl concentration, SiO2 dissolution rates shall be determined. For that purpose, the dissolution experiments already started in funding period 1 will be continued and extended, for what two more aggregates (crushed gravel, rhyolite) will be used among other extensions. By running an SEM/EBSD-analysis, by what size and deformation of single quartz crystals can be determined spatially resolved, quartz will be investigated before and after the dissolution attack. It is of major interest to learn what influence the dissolution attack has on the quartz microstructure and what link between microstructure and dissolution rate exists respectively. 6. By means of an image analysis software, concrete thin sections shall be used for a more quantitative instead qualitative and describing appraisal. The main focus is the detection of cracks to characterize the degree of the cracking more quantitatively (number, width, lengths and area of the cracks) and by deriving an appropriate specific value to compare the degree of damage caused by ASR for different concretes.

在1498研究小组内，子项目5将追求以下6个目标：1。这是澄清，在何种程度上的机械预损伤和循环荷载可以驱动一个临界量的NaCl溶液进入混凝土。 2.对于另一种岩石类型，应验证骨料颗粒中与加工相关的微裂纹的影响。 3.通过nanoCT系统，应确定FIB循环气候储存试验方法期间混凝土棱柱体中形成的ASR凝胶体积。本文的主要目的是阐明是否存在临界凝胶量，如果超过该临界凝胶量，将导致混凝土劣化，该劣化是相应测量的膨胀和凝胶组成的函数。这一信息对于次级项目3的建模特别重要。4.将测量合成ASR凝胶的溶胀压力作为其组成、水含量和量的函数。关于其组成，除了Ca含量之外，这里特别感兴趣的是Na含量，因为它受到外部NaCl供应的影响。此外，还应说明凝胶的溶胀能力是否保持在一定的含水量以下，以及产生有害压力所需的凝胶量。此外，SiO2溶解的膨胀过程中的作用将通过测量膨胀压力的岩石粉末进行人工孔隙解决方案。对于热力学建模，还将确定合成ASR-凝胶的溶解度产物和反应速率。所获得的数据对于在子项目3范围内模拟ASR破坏过程非常重要。5.作为温度和NaCl浓度的函数，应确定SiO2溶解速率。为此，将继续并延长在第一供资期已经开始的溶解实验，为此，除其他扩展外，还将使用另外两种骨料（碎砾石、流纹岩）。通过运行SEM/EBSD分析，通过空间分辨可以确定单个石英晶体的尺寸和变形，将在溶解攻击之前和之后研究石英。了解溶解侵蚀对石英显微结构的影响以及显微结构与溶解速率之间的联系是非常有意义的。6.通过图像分析软件，采用混凝土薄片进行定性和描述性评价，更多的是定量评价。主要重点是裂缝的检测，以更定量地表征裂缝的程度（裂缝的数量，宽度，长度和面积），并通过推导出适当的具体值来比较不同混凝土的ASR造成的损害程度。

项目成果

Alkali‐silica reaction performance testing of concrete considering external alkalis and preexisting microcracks

考虑外部碱和预先存在的微裂纹的混凝土碱硅反应性能测试

• DOI: 10.1002/suco.201600173
• 发表时间: 2017
• 期刊: Structural Concrete
• 影响因子: 3.2
• 作者: Giebson;Voland;Ludwig
• 通讯作者: Ludwig