Masonry Grout

 Masonry grout is a cementitious mixture used to fill cores or cavities in masonry construction. While sually

 added for structural reasons, grout can also increase: fire ratings, security, acoustical performance,

 termite resistance, blast resistance, thermal storage capacity and anchorage capabilities. Grout is

 composed of cement, aggregate, lime (optional) and sufficient water to allow ease of placement and

 ensure complete filling of the grout space. With approval, admixtures may be added to the grout mix. The

 high initial water content of typical grout mixes compensates for water absorption by the masonry during

 and after grout placement. The final water-to-cement ratio is significantly reduced, thus grout develops

 high compressive strength despite its apparent high initial water to cement ratio.

 Generally, grout is used to structurally bond wall elements into a wall system. The most common example

 is in reinforced construction, where grout bonds the steel reinforcing bars to the masonry, allowing them

 to act as one system in resisting loads. Composite walls consist of two wythes of masonry with a solidly

 grouted collar joint with or without reinforcing steel.

 Grouted cores also increase the net cross-sectional area of concrete masonry and permit walls to carry

 higher compressive, shear loads and lateral loads. Masonry cantilever retaining walls are often solidly

 grouted to increase the wall’s weight, and hence resistance to overturning. Grouted masonry construction

 is not required to be reinforced, but typically is for design economy. Reinforced masonry construction,

 however, requires grout to be placed around the reinforcement.