This research is focused on the development of concrete mix by using borosilicate glass micro-filler obtained from the waste of outworn fluorescent lamps. The task of the research is to find the optimal fineness of glass particles, which can improve packing of microparticles in cement matrix to increase the strength properties of concrete. Previous research as well as chemical composition of glass proved that ground glass can be used as an effective concrete component. Borosilicate glass micro-fillers with different grinding degree were used in experiments. Particle grading was determined by using the laser diffraction method. The morphology of microparticles was investigated. The effect of glass powder on cement setting time was checked. It was determined that fine glass particles powder produces a long-term hardening effect. Experimental work includes preparation of samples from standard concrete and concrete with borosilicate glass micro-filler (with particles of different sizes and mixed in different proportions) and testing after the ageing period of 7 and 28 days. The long-term hardened samples were also tested. The compressive strength of concrete samples is decreasing when rough glass powder is used as cement replacement. At the same time fine glass filler with particle size up to 0.1–10 μm allows improvement in mechanical properties of concrete and makes it possible to replace up to 25% of the cement without impairing the strength characteristics of concrete. As a result, concrete with improved water resistance and durability was obtained.