Effect of Alkali Nitrates on the Formation of Silicate Gel Applied in the Surface Treatment of Cementitious Materials

Increasing the durability and extending the lifespan of existing concrete structures are critical challenges in modern infrastructure maintenance. Lithium silicates have emerged as effective concrete densifiers due to their ability to improve surface hardness and resistance to degradation. However, their practical application is often hindered by difficulties in controlling the gelation process, which is crucial for their performance. This study explored the potential of alkali nitrates as gelation agents for lithium silicate systems. Multifaceted investigation of the gelation and ripening processes was conducted to provide deeper insights into the underlying mechanisms. Selected lithium silicate systems were then used to treat cementitious samples to evaluate their performance as concrete densifiers. Prepared silicate systems proved to be structurally stable and able to significantly reduce water penetration, especially in the early stages of water immersion.