Sikadur-31 CF Normal 2-Part Epoxy Structural Adhesive & Repair Mortar

Sikadur-31 CF Normal 2-Part Epoxy Structural Adhesive & Repair Mortar

A moisture-tolerant, thixotropic structural adhesive and repair mortar based on two-component epoxy resin and special fillers. Designed for application between +10°C and +30°C, it combines strong adhesion with a non-sag consistency for professional bonding and repairs.

Product Features

• Easy to mix and apply, with no primer needed on correctly prepared substrates.
• Very good adhesion to many construction materials.
• High initial and ultimate mechanical strength.
• Thixotropic consistency for vertical and overhead applications; tested vertical non-sag thickness up to 15mm.
• Hardens without shrinkage.
• White and dark-grey components provide visual mixing control.
• Good abrasion and chemical resistance.
• Impermeable to liquids and water vapour.

Specifications

• Brand: Sika
• Model: Sikadur-31 CF Normal
• Composition: Two-component epoxy resin with special fillers
• Mixing ratio A:B: 2:1 by weight or volume
• Component A: White; component B: Dark grey; mixed colour: Concrete grey
• Manufacturer-listed mixed density: 1.90 +0.1 kg/L at +23°C, evacuated
• Maximum layer thickness: 30mm
• Vertical non-sag thickness: Up to 15mm, EN 1799
• Shelf life: 24 months from production
• Storage: Original unopened, sealed and undamaged packaging in dry conditions between +5°C and +30°C, protected from direct sunlight.

Application

For experienced professionals only. Suitable as a structural adhesive and mortar for concrete elements, hard natural stone, ceramics, fibre cement, mortar, bricks, masonry, steel, iron, aluminium, wood, polyester, epoxy and glass.

• Repairing corners and edges.
• Filling holes and voids.
• Vertical and overhead repairs.
• Joint filling, crack sealing and joint or crack-edge repair.

How to Use

1. Check substrate strength. Concrete and mortar should generally be older than 28 days, subject to the required minimum strength.
2. Prepare a sound, clean, open-textured surface free from laitance, dirt, oil, grease, old coatings and loose material. Substrates must be dry or mat damp with no standing water. Prepare steel by suitable blast cleaning to a quality similar to Sa 2.5, then vacuum clean.
3. Keep the material, air and substrate between +10°C and +30°C. The substrate must remain at least 3°C above the dew point.
4. Mix components A and B in the specified 2:1 ratio for at least 3 minutes using a slow-speed drill and mixing spindle at no more than 300 rpm, until smooth and uniformly grey. Avoid introducing air.
5. Transfer the mixture into a clean container and mix for approximately 1 further minute at low speed.
6. Brush the adhesive well into the substrate. Keep layers within the 30mm maximum and the 15mm vertical non-sag limit. Follow the project specification for bonding, support and loading.
7. Mix only what can be used within the pot life. Do not mix the next unit until the previous unit has been used.
8. Clean tools immediately with Sika Colma Cleaner. Hardened material requires mechanical removal.

What's in the Box

A two-component Sikadur-31 CF Normal unit containing parts A and B. Sika lists pre-batched 1.2kg and 6kg units; the pack size supplied by this single-option listing is not identified. Confirm the supplied unit size before ordering. Tools and cleaner are not listed as included.

Technical Information

• Consumption: Approximately 1.9 kg/m² per millimetre of thickness.
• Pot life for a 200g mix: approximately 145 minutes at +10°C, 55 minutes at +23°C and 35 minutes at +30°C. Open time at +30°C: approximately 50 minutes.
• Pot life starts when resin and hardener are mixed. Higher temperatures and larger batches shorten working time. Dividing the mixed material into portions can extend workability; components may be cooled before mixing but not below +5°C.
• Compressive strength at +10/+23/+30°C: approximately 30/50/55 N/mm² after 1 day; 45/60/65 N/mm² after 3 days; 55/65/65 N/mm² after 7 days.
• Compressive elastic modulus: approximately 4,600 N/mm² after 14 days at +23°C, ASTM D695.
• Flexural strength at +10/+23/+30°C: approximately 14/25/25 N/mm² after 1 day; 25/30/30 N/mm² after 2 days; 30/35/35 N/mm² after 7 days.
• Tensile strength at +10/+23/+30°C: approximately 4/8/12 N/mm² after 1 day; 12/20/20 N/mm² after 3 days; 17/21/22 N/mm² after 7 days.
• Adhesion to dry or moist concrete after 1 day at +10°C: greater than 4 N/mm² with 100% concrete failure.
• Adhesion to steel: approximately 8 N/mm² after 1 day at +10°C; after 3 days, approximately 12 N/mm² at +10°C, 13 N/mm² at +23°C and 15 N/mm² at +30°C.
• Thermal expansion coefficient: 5.9 × 10⁻⁵ per °C over +23°C to +60°C, EN 1770.
• Heat deflection temperature: +49°C after 7 days curing at +23°C, at 10mm thickness. This is a test result, not a general service-temperature rating.

Certificates

Sika lists testing to EN 1504-4 for structural bonding adhesive and CE marking.