The Examination of the Effect of Water-Soluble Hydrophobic Agents on Physical–Mechanical Parameters and Resistance to Aggressive Environment of Concrete

The aim of this research was to examine the effect of water-based hydrophobic impregnations on concrete in order to improve its durability, chemical resistance, and physical–mechanical parameters. The purpose of this research was to prevent as much water evaporation as possible during concrete hydration, which resulted in the improvement in concrete properties including strength, durability, resistance of concrete in high-pressure water, water tightness, etc. Water-based hydrophobic impregnations based on silane and siloxane, epoxy resin, and oil were chosen to achieve improvements in concrete parameters. The comparison of water-based hydrophobic impregnations with solvent-based hydrophobic impregnations was also performed using the determination of absorbency, water pressure penetration depth, watertightness, concrete penetration depth, and resistance to aggressive environment. The concrete microstructure was observed using a digital microscope and a scanning electron microscope (SEM). Samples with hydrophobic agents exhibited a higher contact angle, lower absorbency, and higher resistance to aggressive environment, when compared to the untreated surfaces, confirming the water repellency of the water-soluble hydrophobic impregnations. The positive effect of hydrophobic agents in the compressive strength was also recorded. Furthermore, the benefit of the addition of 0.1 wt.% of nanocellulose into the hydrophobic impregnations was observed. Based on the obtained results, it was found that the addition of nanocellulose to water-soluble hydrophobic impregnations reduced the depth of pressurized water seepage and increased the compressive strength of the concrete after 28 days by 2 MPa.