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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).

该项目第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裂解和运输过程进行定量描述。研究范围包括ASR损伤前的机械诱导开裂描述、质量传递过程分析和ASR诱导开裂表征。在第一个资助期间，循环四点弯曲试验与测试解决方案的顶部表明，混凝土退化的拉伸区的循环加载梁显着下降。这是湿度引起的残余应力的结果。因此，将考虑额外的试验方案。将更详细地研究疲劳裂纹的间歇性张开和闭合对质量输运过程的影响。在第一个供资期间优化的X射线3D-CT技术将用于各种损伤诱导程序之后的路面混凝土的三维表征。此外，还将比较、分析和评估在顶部有测试溶液的循环加载后或在滚轮测试后钠和氯化物进入混凝土的情况。在第一个资助期内，只有循环气候储存试验表明，疲劳引起的开裂混凝土退化，以及由此产生的增加的钠和氯离子的侵入，导致更大的ASR损害。冻融时间对ASR的影响尚不清楚。在损伤诱导过程中引入的碱的影响在雾室中无法检测到。将使用替代的总量来澄清这种影响。对改性路面混凝土的附加试验（用专用试验水泥代替道路水泥（Na 2 O当量：1.30 M.-%））应阐明疲劳诱导裂纹对ASR的作用，并将作为ASR损伤模型（TP 3）确认的基础。在不同的湿预处理路面混凝土（受损和未受损）上使用各种测试溶液进行的额外吸力测试将完成测试程序，以全面验证数值模型。空间水分和离子传输将同时进行分析，并与相关的裂纹系统。在不同深度上具有不同钠分布的大型混凝土梁将储存在ASR激发气候中。这些测试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构成宏观模型（TP 6）开发和验证的基础。