The time-dependet load-bearing behaviour of concrete is significantly influenced by factors such as composition, production methods, environmental conditions, and load history. Adequate pre-loading of young concrete can enhance its creep behaviour, improve predictability and enable the design of sustainable, material-efficient structures. This study utilises microscopic investigations to examine the microstructure of concrete specimens, with the goal of clarifying the macroscopically observable effects of early preloading on the concrete creep behaviour. Differences between preloaded and non-preloaded concrete specimens are identified and serve as a basis for illuminating the causes of the changes in the mechanical properties. The main emphasis is placed on microstructural densification and increased interlocking of CSH phases. The question to be clarified is whether only time-dependent structural effects are anticipated by the preloading or whether a completely changed structural behaviour is achieved. The observed changes in microstructure provide valuable information for identifying optimal preloading intensities that can enhance long-term mechanical properties without adversely affecting short-term load-bearing behaviour. This study makes a contribution to understand concrete behaviour and guiding the use of preloading techniques for improved structural behaviour and sustainability.