The effect of using granite dust as a component of concrete mixture

The article considers the possibility of significant improvement of technical properties of granite concrete with the addition of granite dust. Concrete investigations were carried out in the "Portland cement - granite dust - sand" system. It is established that the fresh properties of concrete mixtures and the kinetics of concrete hardening on the basis of granite dust slightly differs from the consistency and character of the strength increase of regular concrete. It is characterized by a more intensive of strength gain and a mixture of "sticky" consistency. The addition of granite dust leads to an increase in the average density of concrete. Due to the partial replacement of sand with dust, the microstructure of the cement matrix is compacted, which is the main reason for increasing the strength of concrete with dust. Granite dust has a positive effect on both the early and grade strength of concrete, as well as the strength after 90 and 180 days of hardening. The results of experimental research of concrete filled with granite dust at use of CEM I 32,5 R and CEM I 42,5 R are presented. It can be noted that by using CEM I 32,5 R, the strength increase at the age of 3, 7 and 28 days is 24–25 %, which is slightly higher compared to using CEM I 42,5 R, where the increase in strength is 17–19 % compared to control samples without granite dust. The introduction of granite dust into the concrete mixture leads to a reduction of water absorption by 32–38 % and water penetration by 60–70 %.