Nitomortar 908: Epoxy Patch Repair Mortar

Product Overview

Nitomortar 908 is a general-purpose, high-strength epoxy patch repair mortar manufactured by Fosroc International Limited. It is a two-component product consisting of a white resin and black hardener that are mixed together to form a grey compound for surface application. The product is specifically designed as a blend of silica aggregates bonded together with epoxy resin, creating a durable repair solution for concrete structures.

Key Uses and Applications

Nitomortar 908 is formulated for speedy and permanent repairs to concrete, making it suitable for:

• Spalled or cracked concrete structures - providing lasting repairs to surface damage
• Sea walls - addressing aggressive environmental conditions
• Industrial floors - particularly in chemical handling and process areas
• Bedding of precast concrete beams - ensuring secure placement
• Emergency repairs to concrete structures where strength, impermeability to water, and chemical resistance are essential
• All repair work to concrete and cementitious substrates requiring durable, chemically resistant solutions

Technical Specifications and Properties

Composition and Mix Ratio

Nitomortar 908 is supplied as a two-part colour-blended material in pre-weighed quantities ready for on-site mixing and use. The mixing specifications are:

• Mix ratio: 1:1 by weight or volume
• Appearance when mixed: Even grey colour (two-colour pack provides visual check on correct mixing)
• Minimum applied thickness: 5mm

Strength Properties

The product demonstrates exceptional compressive and mechanical strength:

• Compressive strength at 7 days: Greater than 50 MPa
• Strength comparison: 2-3 times stronger than typical concrete
• Abrasion and impact resistance: Excellent resistance to mechanical wear and impact forces

Curing and Setting Times

• Pot life: 40 minutes at 20°C; 20 minutes at 35°C
• Initial hardness: 24 hours
• Full cure: 7 days
• Minimum application temperature: 5°C

Application Thickness Guidelines

The product can be applied in varying thicknesses depending on location:

• Horizontal locations: Up to 50mm thickness in sections; thicker sections up to 75mm are possible in smaller locations
• Vertical applications: Built-up to a maximum thickness of 12mm
• Greater thicknesses: Achieved by application of subsequent layers, with Nitomortar EL-HB recommended for thicknesses greater than specified

Chemical Resistance

Nitomortar 908 demonstrates excellent chemical resistance due to its low permeability, which retards chemical attack in aggressive environments. Performance data for blocks continually immersed at 20°C includes:

Chemical Substance	Concentration	Rating
Citric acid	10%	Excellent
Tartaric acid	10%	Excellent
Sodium hydroxide	50%	Excellent
Diesel fuel/petrol	100%	Excellent
Sulphuric acid	10%	Very good
Sugar solutions	Saturated	Very good
Lactic acid	10%	Very good
Hydrocarbons	100%	Very good
Phosphoric acid	10%	Very good

Key Advantages

Nitomortar 908 offers multiple performance benefits:

• High strength development - 2 to 3 times stronger than typical concrete
• Early hardness - Initial hardness in 24 hours minimises maintenance disruption
• Quality control - Pre-weighed, quality-controlled materials ensure consistency and reduce site errors
• Chemical resistance - Unaffected by a wide range of acids, alkalis, and industrial chemicals
• Damp condition tolerance - Will cure under damp conditions
• Visual confirmation - Two-colour pack provides visual check on correct mixing
• Aesthetic compatibility - Natural grey colour sympathetic to aesthetic requirements
• Impermeability - Forms a complete impermeable repair unaffected by many forms of chemical attack

Surface Preparation Requirements

Proper substrate preparation is critical for optimal performance:

1. Surface cleaning - Remove dust, unsound material, plaster, oil, paint, grease, corrosion deposits, or algae
2. Surface roughening - Roughen the surface and remove laitance by light scabbling or grit-blasting
3. Edge preparation - Saw cut or cut back repair location extremities to a depth of at least 5mm to avoid feather-edging
4. Repair area breakout - Break out complete repair area to minimum depth of 5mm up to sawn edge
5. Decontamination - Remove oil and grease deposits by steam cleaning, detergent scrubbing, or proprietary degreasers; assess effectiveness by pull-off test

Substrate Priming

Before Nitomortar 908 application, the substrate should be primed using one of two options:

• Nitomortar 903 - Mixed in supplied proportions; add entire hardener contents to base and mix thoroughly for 3 minutes
• Nitobond EP - Alternative priming option for substrate preparation

The mixed primer should be:

• Scrubbed well into prepared substrate
• Ensure all surface imperfections are properly coated
• Avoid puddling in depressions
• Apply second coat if primer absorbed within 30 minutes
• Applied as soon as primer has started to gel but retains surface tack (normally 30 minutes to 4 hours depending on temperature)

Mixing Instructions

Mixing requires careful attention to ensure product uniformity:

1. Mix resin and hardener thoroughly using slow-speed electric drill in suitable container
2. Continue mixing until even grey colour is obtained
3. Full pack mixing is recommended; however, experienced applicators may mix part packs using the stated mix ratio at their own risk
4. Reliable scales should be used to weigh individual components for part pack mixing

Application Method

The mixed Nitomortar 908 is applied by:

• Wood float application - Apply mixed product, pressing firmly into place
• Ensure positive adhesion - Full compaction of material into substrate
• Steel trowel finishing - Finish the applied material with steel trowel
• Minimum thickness compliance - Ensure minimum applied thickness of 5mm is achieved

Coverage and Yield

• Coverage rate: 2m² at 5mm thickness per unit pack
• Theoretical coverage: Based on standard application; practical coverage reduced due to wastage factors and substrate variations

Storage and Shelf Life

• Shelf life: 5 years if kept in cool, dry conditions in original, unopened packs
• Storage conditions: Must maintain cool, dry storage
• Reduced shelf life: May occur if stored at high temperatures and/or high humidity conditions

Cleaning and Removal

Nitomortar 908 must be cleaned immediately after use:

• Cleaning solvent: Fosroc Solvent 10
• Application timing: Immediate removal from tools, equipment, and mixers after use

Supply and Packaging

Nitomortar 908 is supplied as:

• Base component: 5L packs (product code FC340010-5L)
• Hardener component: 5L packs (product code FC340011-5L)
• Total pack size: 10L per complete unit

Complementary products available:

• Nitomortar 903: 6 and 30 litre packs
• Nitobond EP: 1.5 and 6 litre packs
• Fosroc Solvent 10: 4 and 20 litre pails

Limitations and Precautions

• Temperature restrictions - Should not be used when temperature is below 5°C and falling
• Professional consultation - If doubts arise concerning temperature or substrate conditions, consult local Fosroc sales office
• Documentation review - Safety Data Sheet (SDS) available from Fosroc website; must be read before use

References

• [1] Fosroc_Nitomortar_903_TDS.pdf
• [2] Fosroc_Nitomortar_908_TDS.pdf
• [3] Fosroc_Nitomortar_AP_TDS.pdf
• [4] Fosroc_Nitomortar_EL-HB_TDS.pdf