| Popis: |
The influence of mineral fillers with positively and negatively charged electric and surface properties on the frost resistance of powder concretes is studied. The authors put forward a hypothesis that in the processes of hydration and corrosion, where water molecules always participate, an important role is played by the electric and surface properties of the solid phase, which make up the binding system. Concretes where the charge on the surface of the pores and capillaries is strongly shifted to the negative area will be subject to a deeper saturation of the material with water and, consequently, will have less frost resistance. Tests for frost resistance were carried out according to GOST 10060-2012 (clause 5.1), according to the first basic method. It was found that the lowest frost resistance is found in samples of powdered concrete with 30% ground quartz sand, compared with powdered concrete with 30% ground marble and fine-grained concrete C:S = 1:3. The results confirmed hypothesis contained in this work. This is evidenced by the results of changes in the mass of samples during tests for frost resistance. It is proposed to use the obtained data as a theoretical basis for selecting rational compositions of high-frost-resistant concretes, both fine-grained and powdered. |
