In this study, the influence of the polycarboxylates based on superplasticizer (SP) “Semflow MC” at dosages 1.0%, 1.5%, 2.5% by weight of cement on microstructure and properties of concrete was investigated. After 12 months of exposure to water, the compressive strength of concrete increased to 154.04 MPa, corresponding to the HPC. The capillary absorption of water and sulphate containing solutions of HPC depends on amount of SP; absorption of HPC 2.5 does not exceed 0.34%. The depth of penetration of solution in the samples decreases consistently by increasing amount of SP. Analysing the formation of crystalline phase during maturation, the following relationship was found: by increasing testing time from 7 to 28 days the amount of portlandite decreased and calcium hydrosilicate formed. After 12 months of exposure of HPC to sulphate containing solutions (H2SO4, Na2SO4, MgSO4), the following crystalline phases were detected: quartz, plagioclase, calcium silicates (hartrurite and tobermorite), small amount of portlandite and carbonate. The corresponding salt (from solution) compounds were not identified in the samples of concrete. It can be considered that the investigated concrete has high chemical resistance to solutions containing sulphate ions. The porosity of HPC samples varies linearly depending on the added amount of SP. After exposure to the solutions, the amount of micropore (6.10-3…10-2 m) increased for all concrete samples, but the pore distribution in a range of 500 to 1000 m did not change. The obtained results have indicated that workability of HPC increases significantly with the addition of SP. The concrete samples with low W/C ratio and SP content up to 2.5 % are characterized by high chemical resistance in sulphate containing solutions.