How does structural grout differ from traditional masonry mortar, and where is it used?

• A. Structural grout is a low-water, highly flowable, non-shrink grout with aggregate used to fill cores and anchor reinforcement, increasing wall strength.
• B. Structural grout is the same as standard mortar but with color added for visibility.
• C. Structural grout has high water content and shrinks during cure.
• D. Structural grout uses no aggregate and is used only for surface finishes.

Answer: (A)

Structural grout is a cementitious grout designed to fill hollow masonry cores and surround reinforcement. It has low water content, is highly flowable, and is non-shrink while containing aggregate. This combination creates a dense, continuous matrix that bonds to both the masonry units and the reinforcement, developing a strong load path through the wall.

It is placed by pumping or pouring into cores and around bars to anchor reinforcement and transfer loads, which increases wall strength and stiffness—especially in reinforced masonry and seismic-resistant applications.

Traditional masonry mortar, by contrast, is meant to bed and bond masonry units. It has more water and lacks the non-shrink, aggregate-filled formulation, so it’s not used to fill cores or anchor reinforcement and won’t provide the same structural continuity.