Masonry Magazine March 1979 Page. 17
NCMA-TEK
An Information series from National Concrete Masonry Association
Grouting for Concrete
Masonry Walls
Introduction
GROUT IS A MIXTURE of cementitious material, aggregate, and enough water to cause the mixture to flow readily, without segregation, into cores or cavities in the masonry.
In reinforced concrete masonry wall construction, grout often is placed only in wall spaces containing steel reinforcement. The grout bonds the masonry units and steel so that they act together to resist imposed loads. In some reinforced load-bearing masonry walls, all cores with and without reinforcement are grouted to further increase the wall's resistance to loads.
Sometimes grout is used to give added strength to non-reinforced load-bearing concrete masonry walls. This is accomplished by filling a portion or all of the cores; for example, filling the cores of the units forming the jamb of a door. It is also used to fill bond beam cavities and occasionally to fill the collar joint of a 2-wythe wall.
Methods for laying the units, placing steel reinforcement and grouting of cavities will vary with the job size, available equipment, and the mason contractor's preference.
Wall Construction
LAY UP solid or hollow concrete masonry units so that they are aligned to form an unobstructed, continuous series of vertical spaces within the wall. Spaces that will contain reinforcement should be at least 2 inches wide.
FIGURE 2 Pumping grout.
FIGURE 1 TYPICAL REINFORCED CONCRETE MASONRY CONSTRUCTION
USING THE LOW-LIFT GROUTING TECHNIQUE
Vertical steel-Lap 30 bar
diameters at splices; hold
in position at intervals of
192 diameters.
Steel in Bond Beams is set
in place as wall is laid up.
Place metal lath under
bond beam to confine grout.
Floor Slab.
Stop grout 1½" from top.
Place grout in lifts not to
exceed four feet; puddle or
vibrate in place.
Cells containing steel are
filled solidly with grout:
vertical cells should provide
a continuous cavity, free of
mortar droppings, and at
least 2 x 3 inches in size.
Place mortar on cross webs
adjacent to cells which will be
grouted