Maintenance & Repair Procedures Flashcards

Which repair method is most appropriate for restoring structural integrity to a dormant (non-moving) crack in a concrete beam?

Answer: Epoxy injection

Epoxy injection bonds the crack faces of dormant cracks and restores structural continuity.

A crack in a slab-on-grade keeps opening and closing with temperature changes. What is the best repair approach?

Answer: Rout and seal with a flexible elastomeric sealant

Active cracks need a flexible sealant that can take the movement, because rigid fillers will re-crack.

When repairing concrete spalled by corroding reinforcement, industry practice (e.g., ICRI guidelines) calls for:

Answer: Removing concrete to create clearance behind the corroded bar, cleaning the steel, then patching

Undercutting behind the bar (typically about 3/4 in. minimum) lets the repair material fully encase the cleaned reinforcement.

White powdery deposits appear on a brick wall after heavy rains. What should the first maintenance step be?

Answer: Find and stop the source of water moving through the masonry

Efflorescence comes from water carrying soluble salts to the surface, so controlling the moisture source comes first.

When repointing older soft brick masonry, the new mortar should be:

Answer: Softer and more permeable than the masonry units

Mortar that is softer than the units (e.g., Type N or O, lime-rich) prevents spalling of the brick because the mortar acts as the sacrificial element.

Blisters forming in a built-up roof membrane are most commonly caused by:

Answer: Trapped moisture or air between plies that expands with heat

Moisture or air trapped between plies expands under solar heat and lifts the membrane into blisters.

When replacing a failed sealant joint, why is a backer rod installed?

Answer: To control sealant depth and prevent three-sided adhesion

The backer rod sets the proper hourglass profile and depth and prevents three-sided adhesion, which causes premature failure.