Grouting is the process of injecting materials into cracks or voids in structures to increase their strength and stability. Common grouting materials include cement, sand, water, and chemical substances. Grouting fills gaps, seals cracks, and strengthens foundations. The main types of grouting are cement grouting, chemical grouting, structural grouting, bentonite grouting, bituminous grouting, and resin grouting. Each has different applications depending on the material properties and permeability of the structure.