What is used to hold blocks together in masonry?

• A. Grout
• B. Rebar
• C. Mortar
• D. Glue

Answer: (C)

Mortar binds blocks together in masonry. It’s a cementitious mix of cement, sand, and water that fills the joints between blocks and adheres them to form a solid, unified wall. As mortar cures, it hardens and distributes loads across the masonry while sealing joints against moisture and air. Grout is a thicker material used to fill hollow cores or spaces for added strength and to surround reinforcement; it’s not the primary bonding agent between blocks. Rebar adds tensile strength when placed in cores and then grouted, but it doesn’t hold the blocks together by itself. Glue isn’t used for structural masonry because it doesn’t provide the needed durability and strength.