Nitomortar 908: Technical Details, Specifications, Features, and Applications

Product Overview

Nitomortar 908 is a general-purpose, high-strength epoxy patch repair mortar manufactured by Fosroc International Limited. It is specifically formulated for speedy and permanent repairs to spalled or cracked concrete structures, providing exceptional strength, impermeability, and chemical resistance in demanding environments.

Product Composition and Description

Nitomortar 908 consists of a two-component system comprising silica aggregates bonded together with epoxy resin. The product is supplied as a two-part color-blended material in pre-weighed quantities, consisting of:

• White resin component (base)
• Black hardener component

When thoroughly mixed, these components form a grey compound designed for immediate on-site preparation and application. The product is engineered to quickly cure and form a completely impermeable repair unaffected by many forms of chemical attack.

Key Technical Specifications

Physical Properties

Property	Specification
Compressive Strength (7 days)	>50 MPa
Pot Life	40 minutes @ 20°C; 20 minutes @ 35°C
Mix Ratio	1:1 by weight or volume
Initial Hardness	24 hours
Full Cure	7 days
Minimum Application Temperature	5°C
Minimum Applied Thickness	5mm
Coverage	2m² at 5mm thickness

Design Criteria for Application

Nitomortar 908 has specific thickness limitations depending on application orientation:

• Horizontal applications: Can be applied in sections up to 50mm thickness. Thicker sections up to 75mm are possible in smaller locations, depending on repair area configuration and exposed reinforcing steel volume
• Vertical applications: Material should be built-up to a maximum thickness of 12mm
• Greater thicknesses: For repairs requiring thicknesses greater than specified, Nitomortar EL-HB should be used instead
• Layered application: Greater thicknesses can be achieved through application of subsequent layers

Chemical Resistance

Nitomortar 908 demonstrates excellent to very good chemical resistance when blocks are continually immersed at 20°C. The low permeability of the product retards chemical attack in aggressive environments:

Chemical	Concentration	Resistance
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

Performance Advantages

Mechanical Properties

• 2–3 times stronger than typical concrete
• Excellent resistance to abrasion and impact
• Early development of initial hardness, minimizing maintenance disruption
• Strengths exceeding concrete to which the material is applied

Durability and Application Features

• Pre-weighed quality-controlled materials ensure consistency and reduce risk of site errors
• Two-color pack (white/black) provides visual check on correct mixing, achieving uniform grey color when properly mixed
• Unaffected by a wide range of acids, alkalis, and industrial chemicals
• Will cure under damp conditions, providing flexibility in application
• Natural grey color sympathetic to aesthetic requirements
• Impermeability to water and resistance to aggressive chemicals

Application Areas and Uses

Nitomortar 908 is designed for:

• Speedy and permanent repairs to spalled or cracked concrete structures
• Bedding in of precast concrete beams
• All repair work to concrete and cementitious substrates where strength, impermeability to water, and chemical resistance is essential
• Emergency repairs to concrete structures, sea walls, and industrial floors
• Chemical handling and process areas requiring maximum chemical resistance
• General concrete patching applications in demanding environments

Surface Preparation and Application Process

Preparation Requirements

1. Clean the surface and remove dust, unsound material, plaster, oil, paint, grease, corrosion deposits, or algae
2. Roughen the surface and remove laitance by light scabbling or grit-blasting
3. Saw cut or cut back extremities to at least 5mm depth to avoid feather-edging
4. Break out the complete repair area to minimum 5mm depth
5. Remove oil and grease deposits by steam cleaning, detergent scrubbing, or proprietary degreaser

Substrate Priming

The substrate should be primed using either:

• Nitomortar 903 (epoxy primer), or
• Nitobond EP (alternative primer)

Nitomortar 908 can be applied as soon as the primer has started to gel but still has surface "tack," normally between 30 minutes and 4 hours depending on ambient and substrate temperatures.

Mixing Instructions

• Thoroughly mix resin (white) and hardener (black) using a slow-speed electric drill in a suitable container
• Mix continuously until an even grey color is obtained
• Full packs are recommended for mixing, though experienced applicators may mix part packs using the 1:1 ratio
• Reliable scales should be used for part-pack mixing to ensure correct proportioning

Application Method

• Apply mixed Nitomortar 908 to prepared substrate using a wood float, pressing firmly to ensure positive adhesion and full compaction
• Finish with a steel trowel
• Minimum applied thickness: 5mm

Cleaning and Removal

Nitomortar 908 should be removed from tools, equipment, and mixers with Fosroc Solvent 10 immediately after use.

Storage and Shelf Life

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

Limitations

• Should not be used when temperature is below 5°C and falling
• Temperature sensitivity requires consultation with Fosroc if doubts arise concerning temperature or substrate conditions
• Thickness restrictions apply depending on application orientation and location

Supply and Availability

Product	Pack Size	Product Code
Nitomortar 908 Base	5L (10L pack)	FC340010-5L
Nitomortar 908 Hardener	5L (10L pack)	FC340011-5L
Nitomortar 903 (Primer)	6L and 30L packs	—
Nitobond EP (Primer)	1.5L and 6L packs	—
Fosroc Solvent 10	4L and 20L pails	—

Coverage Data

Theoretical coverage: 2m² at 5mm thickness

Note: Due to wastage factors and the variety and nature of possible substrates, practical coverage figures will be reduced.

Safety and Documentation

A Safety Data Sheet (SDS) is available from the Fosroc website and should be read carefully prior to use, as application or performance data may change over time. In emergency situations, contact any Poisons Information Centre (phone 13 11 26 within Australia) or a doctor for advice.

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