The durability of building materials is a key parameter in sustainable construction. A premature deterioration of concrete structures occurs e.g. in sewage water pipelines and other concrete waste water systems due to microbial activity of sulphate-reducing bacteria (SRB) and sulphur-oxidizing bacteria (SOB). To prolong the life time of concrete structures, concrete durability in an aggressive sulphate environment can be improved by partial replacement of cement by several waste materials. Incorporation of slag, silica fume or zeolite into concrete composites can positively influence important concrete characteristics such as water absorption capacity. Thus the waste-based concretes not only contribute to the increased durability of structures but also to minimization of wastes by using their in building industry. In addition, by saving the raw materials for cement production, they can be considered as resource-efficient materials and thus green building materials as well. This paper presents the results of testing water absorption capacities of concrete composites of different compositions after the 60-day exposure to sulphate bacterial environment. In 4 mixtures, cement was replaced with granulated blast furnace slag in proportions 65, 75, 85 and 95 wt. % and in 1 mixture hybrid-cement was used. The concrete specimens with and without any cement replacement were placed in sulphate environment with bacteria Acidithiobacillus thiooxidans for 60 days. The experiments proceeded under model laboratory conditions. Water absorption capacities were measured according to common test procedures before and after the experiments.