Grout is a particularly fluid form of concrete used to fill gaps. It is used in construction to embed rebars in masonry walls, connect sections of pre-cast concrete, fill voids, and seal joints such as those between tiles. Grout is generally a mixture of water, cement, sand, often color tint, and sometimes fine gravel (if it is being used to fill large spaces such as the cores of concrete blocks). Unlike other structural pastes such as plaster or joint compound, correctly-mixed and -applied grout forms a waterproof seal.
Although both are applied as a thick emulsion and harden over time, grout is distinguished from its close relative mortar by its viscosity; grout is thin so it flows readily into gaps, while mortar is thick enough to support not only its own weight, but also that of masonry placed on top of it
Tools associated with groutwork include:
1) Grout saw or grout scraper a manual tool for removal of old and discolored grout. The blade is usually composed of tungsten carbide.
2) Grout float a trowel-like tool for smoothing the surface of a grout line, typically made of rubber or soft plastic.
3) Grout sealer a water-based or solvent-based sealant applied over dried grout that resists water, oil, and acid-based contaminants.
4) Dremel grout attachment an attachment guide used in a die grinder for faster removal of old grout than a standard grout saw.
5) Pointing Trowel Used for applying grout in flagstone, and other stone works.