Self-Leveling Concrete Topping with Aggregate Surface - Ardex K 521™ 50 LB

Rapid Concrete Resurfacing

ARDEX K 521™ is a self-leveling, pourable topping designed for rapid resurfacing of indoor concrete. It can be applied at a minimum thickness of 3/8″ (9 mm) and up to a maximum thickness of 2″ (5 cm). ARDEX K 521 creates a polished, “aggregate-exposed” finish, with polishing possible as soon as 24 hours after application.

Key Features

• A mixture of Portland cement, hydraulic cements, and specialty aggregates
• Ideal for resurfacing indoor concrete
• Can be walked on in 2 to 3 hours; polishing can begin in as little as 24 hours
• Dual water ratio for versatility
• Suitable for interior floors only

Standards

Tested in accordance with ASTM C1708

INSTALLATION

Mixing Ratio: 3 1/2 or 3 3/4 quarts (3.31 or 3.55 L) of water per 50 lb. (22.7 kg) bag
Coverage: 14 – 15 sq. ft. per bag at 3/8” (1.3 – 1.4 sq. m at 9 mm)
9 – 10 sq. ft. per bag at 1/2” (0.8 – 0.9 sq. m at 12 mm)

PERFORMANCE

Flow time: 10 minutes
Compressive strength (ASTM C109/mod – air cure only): 6,800 psi (476 kg/sq. cm.) at 28 days
Flexural strength (ASTM C348): 1,300 psi (91 kg/sq. cm.) at 28 days
Walkable: 2 – 3 hours (without E 25); 24 hours (with E 25)
Polishable: 24 hours (without E 25); 48 hours (with E 25)
Available Colors: Gray
VOC: 0
Packaging: 50 lb. (22.7 kg) net weight bag
Storage: Store in a cool, dry area. Do not leave bags exposed to sun.
Shelf life: Nine months, if unopened

• Product Overview
• Tech Data Sheet
• Safety Data Sheet