Effect of the type of coarse aggregate on structure and properties of ultra-high strength concrete

超高强度混凝土的生产需要高强度骨料。通常使用玄武岩和石英岩或石英砂。然而，还有许多其他类型的岩石可能是可用的。对于其中一些类型，预计在骨料-粘合剂界面上发生化学反应，从而产生非常强的附着力。同时，关于不同岩石类型对超高强度混凝土力学性能影响的研究很少，也没有研究不同岩石类型对超高强度混凝土力学性能影响的原因。这正是这个研究项目的目的。因此，将测量岩石类型对抗压强度、压缩应力-应变曲线、弯曲抗拉强度和冲击行为的影响的可靠数据。观察到的差异的原因将通过研究骨料，特别是骨料-粘结剂界面的高分辨率分析方法来分析。特别是，透射电子显微镜将与聚焦离子束样品制备方法结合使用。与扫描电子显微镜相比，即使用于化学分析，透射电子显微镜的分辨率也在纳米范围内。因此，该研究项目为超高强度混凝土的更可持续和更经济的应用提供了重要的基础，更广泛的基础材料和对不同岩石类型影响的科学理解。超高强度混凝土的重要性显然会随着可预见的建筑材料规则的建立而增长，同样在德国。

The production of ultra-high strength concrete requires high-strength aggregates. Basalt and quartzite or quartz sand are commonly used. Nevertheless, there are many other rock types that may be usable. With some of these types, chemical reactions at the aggregate-binder interface are to be expected, resulting in a very strong adhesion. At the same time there are only very few investigations on the influence of different rock types on the mechanical behaviour of ultra-high strength concrete and no investigations in which the reasons for the different behaviour were examined. Exactly this is the aim of the research project. Therefore reliable data on the influence of the rock type on compressive strength, the stress-strain curve under compression, the tensile strength in bending and the behaviour under shock will be measured. The reasons for the observed differences will be analyzed by investigating the aggregate and especially the aggregate-binder interface by high-resolution analytic methods. In particular, transmission electron microscopy will be used in combination with focused ion beam methods of sample preparation. In contrast to scanning electron microscopy, transmission electron microscopy has a resolution in the nanometer range even if used for chemical analysis. The research project therefore generates an important basis for a more sustainable and economic application of ultra-high strength concrete, with a broader range of basic materials and a scientific understanding of the effects of different rock types. The importance of ultra-high strength concrete will clearly grow by the foreseeable establishment of rules for this building material, also in Germany.