Due to its many fields of application, there are high demands for high-performance concrete. A precise knowledge about this building material is crucial. Therefore, an understanding of the composition and processing of concrete, and its resulting properties are enormously important to meeting the demands in today's construction. This work deals with the use of an increasingly aging premix for high performance concrete. In order to find out if premixes for high-performance concrete have, so to speak, an expiration date, tests were carried out on fresh concrete as well as on hardened concrete using premixes of different ages. For this purpose, premixes of the dry components with varying mixing times were produced at the beginning of the experiments. Consequently, in addition to the age of a premix, the influence of the dry mixing time was also investigated. The mixing times varied between 1.5 and 480 minutes. Upon completion, the premixes were stored in airtight containers. After forty-eight hours, four weeks, and nine weeks the fresh concrete production took place, in which the desired amount of premixes was taken out of the containers. Regarding the fresh concrete, the slump size, the funnel outlet time, the air pore content, the fresh concrete raw density, the particle size distribution and the thixotropy were categorized. After which the fresh concrete was placed for 24 hours in standardized prism molds, whereby the heat of hydration was measured. At the end of these 24 hours, the bending tensile strength and compressive strength were tested on the prisms. The measurement data investigated in this work examines the results of the respective experiments regarding mixing duration and age of the premix. The results do not clearly determine whether the age of the premix has a major influence on solid and fresh concrete properties. However, with regard to the mixing time, more significant differences in the material data can be seen.