This diploma thesis focuses on the study of possibilities for utilizing
sludge–water generated during the recycling of fresh concrete as mixing water for the production of structural concrete. The aim of the thesis was to comprehensively assess the properties of sludge–water obtained from different concrete plants and to evaluate its influence on the properties of fresh and hardened concrete when partially or fully replacing potable mixing water.
Within the experimental part, the physical and chemical properties of the sludge–water were analyzed, in particular its density over time, solids content, pH value, chemical composition, and mineral phases determined by X-ray diffraction. Subsequently, experimental concrete mixtures with different proportions of sludge–water were designed and produced, and selected properties of fresh concrete as well as the mechanical properties of hardened concrete at various ages were evaluated.
Based on the evaluation of the results, it was demonstrated that sludge–water exhibits variable properties depending on the time and location of sampling, while its use in concrete is feasible under certain conditions. An appropriately selected proportion of sludge–water did not adversely affect the basic mechanical properties of concrete and, in some cases, led to a slight improvement. The results of the thesis confirm the potential of sludge–water as an alternative source of mixing water and contribute to more sustainable water management in the concrete industry.