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Bewertung des Einflusses einer mechanisch induzierten Rissbildung auf den Verlauf der schädigenden AKR mit innovativen Prüftechniken

使用创新测试技术评估机械诱导裂纹形成对 AKR 破坏过程的影响

基本信息

批准号：
202323017
负责人：
Professorin Dr. Birgit Meng
金额：
--
依托单位：
Fachbereich 7.1: Baustoffe
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 2019-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/202323017?language=en
关键词：
Bewertung des Einflusses einer mechanisch

项目摘要

The aim of part 4 of the project is to complete the basis for numerical models on meso and micro scale by fundamental tests. The focus is on the quantitative description of the cracking and transport processes by means of innovative measurement techniques. The research spectrum includes the de-scription of the mechanically induced cracking prior to ASR damage, the analyses of the mass transport processes and the characterization of the resulting ASR-induced cracking. During the first funding period, cyclic four-point bending tests with test solution on top showed that concrete degradation in the tensile zone of the cyclic loaded beam significantly decreased. This is a result of the hygric induced residual stress. For this reason an additional test regime will be considered. The influence of the intermittent opening and closing of fatigue induced cracks on the mass transport processes will be investigated in more detail. X-Ray-3D-CT techniques, which were optimized during the first funding period, will be used for three dimensional characterization of the road surface concrete after various damage inducing procedures. Additionally, sodium and chloride ingress into the concrete after cyclic loading with test solution on top or after rolling wheel test will be compared, analyzed and assessed. During the first funding period only the cyclic climate storage test revealed that fatigue induced cracking concrete degradation, and the resulting increased sodium and chloride ingression, led to greater ASR damage. The effect of the freeze thaw period on ASR was still unclear. The effect of the alkalis, introduced during the damage inducing procedures, was not detectable in the fog chamber. Alternative aggregates will be used to clarify this effect. Additional tests on a modified road surface concrete (substitution of road cement by special test cement (Na2Oequivalent: 1,30 M.-%)) shall clarify the role of the fatigue induced cracking on ASR and will be the basis for the validation of the ASR damage model (TP3). Additional suction tests using various test solutions on different hygric preconditioned road surface concretes (damaged and undamaged) will complete the test program for a comprehensive validation of the numerical model. The spatial moisture and ion transport will be analyzed simultaneously and correlated to the associated crack system. Large concrete beams with different sodium distributions over the depth will be stored in an ASR provoking climate. These tests will elucidate the influence of a heterogeneous ASR severity that varies with depth on the deformation. The deformation and the moisture distribution, measured vertically, will form the basis for the development and validation of a macroscopic model (TP6).

项目第4部分的目的是通过基本试验完成中、微观尺度数值模型的基础。重点是通过创新的测量技术对开裂和输运过程进行定量描述。研究光谱包括在ASR损伤之前的机械诱导开裂的描述，质量传递过程的分析以及由此产生的ASR诱导开裂的表征。在第一期资助期内，顶部加试验溶液的循环四点弯曲试验表明，循环加载梁受拉区混凝土劣化明显减少。这是水气引起的残余应力的结果。由于这个原因，将考虑一个额外的测试制度。疲劳裂纹的间歇性开闭对质量输运过程的影响将被更详细地研究。X-Ray-3D-CT技术在第一个资助期内进行了优化，将用于各种损伤诱导程序后路面混凝土的三维表征。另外，对顶部加试验溶液循环加载后和滚轮试验后的钠、氯离子进入混凝土的情况进行比较、分析和评估。在第一个资助期内，只有循环气候储存试验显示疲劳引起的混凝土开裂退化，以及由此导致的钠和氯化物侵入增加，导致更大的ASR损伤。冻融期对ASR的影响尚不清楚。在破坏诱导过程中引入的碱的影响在雾室中是检测不到的。我们将使用替代聚合来阐明这一效应。在改性路面混凝土上进行的额外试验（用特殊试验水泥（na2o当量：1.30 M.-%）替代道路水泥）将阐明疲劳诱导开裂对ASR的作用，并将成为验证ASR损伤模型（TP3）的基础。额外的吸力测试使用不同的测试溶液在不同的水预处理路面混凝土（损坏和未损坏）将完成测试程序，以全面验证数值模型。空间水分和离子输运将同时进行分析，并与相关的裂纹系统进行关联。具有不同深度钠分布的大型混凝土梁将存储在引发ASR的气候中。这些试验将阐明随深度变化的非均匀ASR严重程度对变形的影响。垂直测量的变形和水分分布将成为开发和验证宏观模型（TP6）的基础。