The characterization of the rheological properties of suspension, mortar and concrete under the influence of hydration, temperature, pressure and vibration

保持混合物的均质性是进行流变学测量的先决条件。有了新的测量技术，流变学测量过程中的均匀性将被记录在两个流变仪(MODUL II)中。在已知的流变仪中，剪切诱导的偏析发生在预剪切相。在接下来的测量阶段中，不均匀的材料因此被测量。基于沉积过程的不均质性也不能被识别。IWB有一台独特的机器(KNIELE KKM-RT 22.5/15)，可用作搅拌机和流变仪，避免预剪时材料的不均匀。本研究项目涉及在单个设备中生产和(重复)测定混合水平的预剪流变参数！浓缩式搅拌机允许通过调整搅拌强度来绘制搅拌技术和粒度的范围。此外，该机器还可以在预剪切阶段主动使混合物均化，并抵消沉淀。触变性引起的结构退化而不降低混合质量。根据MODUL II，颗粒悬浮液的流变性将由两个已知的流变仪来测定。特别注意了剪切和沉积引起的不均匀性。ICAR和KNIELE的容器中的不均匀是通过四个微型湿度探头通过湿度测量值和基于雷达的电导率的变化在本地检测到的。KNIELE中的搅拌器摄像头使识别实际剪切区域(剪切半径)成为可能，并在计算过程中将其考虑在内。只有在能够正确测量的情况下，才有可能量化新拌混凝土的流变特性，并了解新旧状态下各组分之间的相互关系。这些探头还可以通过所谓的雷达电导率来测量悬浮液的离子电导率。新混凝土性能的变化是否可以用离子导电性随时间的变化来解释，这还有待研究。这样就实现了与MODUL I的连接，从而找到了表征新拌砂浆或混凝土性能的进一步参数。进一步连接到模块I和模块III将通过基于流变学的混合料开发来实现。对于堆积密度优化配合比设计，对水和混凝土外加剂的需求是通过对搅拌机原始数据的分析确定的(MODUL III)。混合探头还为雷达测量电导率(MODUL I)的评估提供了必要的测量值。为了能够在其他边界条件下进行预剪切相的主动均一化流变性测量，还对KNIELE进行了扩展。到压力室、温度控制单元、用于振动混凝土的振动单元和热量计。

Maintaining the homogeneity of the mixture is a prerequisite for carrying out rheological measurements. With new measurement techniques, the homogeneity during rheological measurements is to be recorded in two rheometers (MODUL II). In the known rheometers, a shear-induced segregation takes place in the pre-shear phase. In the following measuring phase, a material which is not homogeneous is thus measured. Inhomogeneities, which are based on sedimentation processes, cannot be recognized either. The IWB has a unique machine (KNIELE KKM-RT 22.5/15) that can be used as a mixer and as a rheometer and avoid inhomogeneities of the material during preshear.This research project involves the production and (repeated) determination of the rheological parameters in a single device with preshear on the level of mixing! The intensive-mixer allows the range of mixing techniques and sizes to be mapped by adapting the mixing intensity.In addition, the machine can actively homogenize the mixture in the pre-shear phase and counteract sedimentation. The structure caused by thixotropy is degraded without reducing the mixing quality.According to MODUL II, the rheological properties of granular suspensions are to be determined by two known rheometers. Particular attention is paid to the inhomogeneities caused by shear and sedimentation. Inhomogeneities in the vessels of the ICAR and the KNIELE are detected locally by means of four miniature moisture probes, via changes in the measured values for moisture and the radar-based conductivity. A mixer camera in the KNIELE makes it possible to identify the actual sheared area (shear-radius) and to take it into account during the calculation. Only with the ability to correctly measure it is possible to quantify the rheological properties of fresh concrete and to understand the correlation between the proportions of the components in the fresh state.The probes also measure the ionic conductivity of the suspension via the so-called radar-based conductivity. It is to be investigated whether changes in the fresh concrete properties can be explained by changes in the ionic conductivity over time. The connection to MODUL I is thus achieved and a further parameter for the characterization of the fresh mortar or concrete properties would thus be found.Further connections to the MODULE I and III will be carried out by the rheology-based mixture development. For packing-density optimized mix designs the demand for water and concrete additives is determined by the analysis of the mixer raw data (MODUL III). The mixing probes also supply the necessary measured values for the evaluation by the radar-measured conductivity (MODUL I). In order to be able to carry out the rheological measurements with active homogenization in the pre-shear phase under other boundary conditions, the KNIELE is also expanded. To a pressure cell, a temperature control unit, a vibration unit for vibrating concrete and a calorimeter.