Construction methods · Finishing, articulation and maintenance

Deck waterproofing and drainage

Concrete decks under asphalt are protected by a membrane (sprayed polyurethane or methacrylate, sheet bitumen or liquid systems) that keeps chloride-laden water off the reinforcement. With gullies, drains and drip details it is the difference between a deck that lasts and one that delaminates.

How bridges get built · Finishing, articulation and maintenance · Deck waterproofing and drainage

Also called: bridge deck membrane, waterproofing, deck drainage

How it is done

Prepare the deck: grit blast, dry, prime; test adhesion.
Apply the membrane to the specified thickness with laps and upstands at kerbs, joints and drains; protect with a board or a sand asphalt layer.
Install gullies at low points and drainage pipes to ground level; keep water off the piers and bearings.

Where it fits

All concrete decks with asphalt surfacing; steel decks under polymer overlays have their own systems.

Where it does not

Membranes applied to damp or dusty decks; drains that discharge onto the pier.

Plant, pace and money

PlantBlasting, spray rigs, thickness gauges.

Productivity1,000-3,000 m2 per day.

CostUSD 30-70 per m2.

Risks and controls

What goes wrong

Blistering, pinholes, damage from paving plant, blocked drains.

Quality assurance

Adhesion and thickness tests, holiday testing, drainage flow test.

Examples

Standard on Korean, European and Gulf decks; US decks often use bare concrete with sealers instead.