Grout
High slump (8 - 10") concrete. From the Swedish word "groot" which meant porridge.
- Used to fill cells in hollow units to increase assembly strength and to hold reinforced steel in place.
- Basic Ingredients:
- Portland cement - Type I or II.
- Fine aggregate (sand): maximum size £ 1/4".
- Coarse aggregate (pea gravel): maximum size £ 3/4".
- Lime (seldom added).
- Water: high water / cement ratio to ensure good flowability and complete filling of voids.
- Admixtures: grout aid - used for high lift, increases fluidity and water retention as well as promoting expansion of grout.
- Types of Grout:
- Fine (more commonly used).
- Coarse.
- Compressive Strength:
- Indicator of Q.C.
- 1992 ACI requires grout compressive strength, (f `g) to at least equal the specific masonry
compressive, (f `m), strength and
³ 2000 psi at 28 days.
- '97 UBC 2103.4.1 only requires that f 'g ³ 2000 psi.
- Placement:
- Pore - total height of masonry to be grouted prior to erection of more units.
- Lift - height of grout placed in a single continuous operation prior to consolidation.
- Low lift: height is £ 5'
- High lift: 5' < height £ 24'. Cleanout openings in bottom course at every vertical bar to check grout.
- Consolidation - eliminate voids and promote flow around reinforcement. For lifts > 12", must use mechanical vibrators.
See Masonry Council for supplemental information on grout.
