TABLE OF CONTENTS Concrete block basement walls often require steel reinforcing for added strength. In reinforced concrete block construction, the cores of the hollow units are pumped with grout to secure the reinforcing steel and bond it to the masonry. All of the cores of a concrete block wall may be grouted with reinforcement spaced every few cores, or the grout may be limited only to the cores which contain reinforcement.
If only isolated cores of a concrete block wall will be grouted, the cores that will be grouted must be fully bedded in mortar, including the webs and face shell flanges. This will prevent the grout from flowing beyond its intended location. If the whole wall is to be grouted, the face shells are mortared as usual, but the webs are not. This allows the grout to flow laterally inside the wall for better bond. Spacers are used to maintain alignment of the vertical reinforcement to assure that grout completely surrounds the steel for full embedment and proper structural performance. Protrusions or fins of mortar which project into the cores will interfere with proper flow and distribution of the grout and could prevent complete bonding.
The low-lift method of grouting a wall is done in 8-in. lifts as the wall is laid up. Grout should be well mixed to avoid segregation of materials, and carefully poured to avoid splashing on the top of the units, since dried grout will prevent proper mortar bond at the succeeding bed joint.
