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测试来完成MESO和MICRO量表的数值模型的基础。重点是通过创新的测量技术对破裂和运输过程的定量描述。研究范围包括在ASR损伤之前的机械诱导的裂纹，质量传输过程的分析以及所得ASR诱导的裂纹的表征。在第一个资金期间，循环四点弯曲测试在顶部进行测试溶液表明，环状载荷束的拉伸区的混凝土降解显着降低。这是湿法诱导的残留应力的结果。因此，将考虑额外的测试制度。将更详细地研究疲劳感应裂缝对疲劳感应裂纹的影响和结束的影响。在第一个融资期间对X射线3D-CT技术进行了优化，将在各种损害诱导程序后用于对路面混凝土的三维表征。此外，将在顶部或滚轮测试后用测试溶液进行循环载荷后，将钠和氯化物进入混凝土中，进行比较，分析和评估。在第一个资金期间，只有环状气候储存测试表明疲劳会诱导破裂的混凝土降解，并导致钠和氯化物的增加增加，从而造成了更大的ASR损害。冻结时期对ASR的影响仍不清楚。在造成损害过程中引入的碱的作用在雾室中无法检测到。替代骨料将用于阐明这种效果。对改良的道路表面混凝土的其他测试（通过特殊测试水泥取代道路水泥（Na2oQuelentent：1,30 m .-％））应阐明疲劳引起的ASR疲劳的作用，并将成为验证ASR损害模型（TP3）的基础。使用各种测试解决方案进行的其他吸力测试在不同的湿论预处理道路表面混凝土上（受损和未损坏）将完成测试程序，以全面验证数值模型。空间水分和离子传输将同时分析并与相关的裂纹系统相关。在深度上具有不同钠分布的大型混凝土梁将存储在ASR挑衅的气候中。这些测试将阐明随着变形的深度变化的异质ASR严重性的影响。垂直测量的变形和水分分布将构成开发和验证宏观模型（TP6）的基础。