Conbextra EP65 Plus: Ultra High Strength Epoxy Grout

Product Overview

Conbextra EP65 Plus is a rapid hardening, ultra high strength epoxy grout manufactured by Fosroc, designed for precision heavy duty multi-purpose engineering applications. It is supplied as a two-component system consisting of epoxy resin incorporating inert fillers and a hardener component that produces a highly fluid grout suitable for dynamic and repetitive load applications.

Product Composition and Supply

The product is formulated as a two-part epoxy system with the following supply specifications:

• Format: 14 litre pre-weighed packs
• Base Component: Conbextra EP65 Plus (Base) - Product Code FC524460-11.5L
• Hardener Component: Conbextra EP65 Plus (Hardener) - Product Code FC524470-2.5L

The components are supplied in correct mix proportions designed for whole pack mixing to ensure consistent flow and mechanical properties.

Design Criteria and Application Range

Conbextra EP65 Plus is formulated for flow application into gaps under base plates ranging from 10mm to 100mm in width. The product can be placed in thicknesses from 10mm up to 100mm in a single pour, depending on the dimensions of the grout pour and method of application.

Key Features and Advantages

Mechanical Properties

• Very high compressive, tensile and flexural strengths
• High early strength gain with fast, convenient installation
• Low creep characteristics under sustained loading
• Excellent effective bearing area (EBA) design for optimal load transfer

Performance Characteristics

• Resistant to repetitive dynamic loads - suitable for machinery and equipment subjected to heavy dynamic or mobile loads
• Non-shrink formulation - ensures complete surface contact and bond
• Excellent chemical resistance
• Water displacement capability for underwater applications

Specifications and Performance Data

Compressive Strength

Conbextra EP65 Plus demonstrates exceptional compressive strength development across multiple curing periods:

Cure Temperature	2 hours	3 hours	4 hours	5 hours	12 hours	1 day	3 days	7 days
10°C	0 MPa	5 MPa	15 MPa	25 MPa	45 MPa	60 MPa	100 MPa	110 MPa
23°C	40 MPa	70 MPa	80 MPa	85 MPa	90 MPa	105 MPa	115 MPa	125 MPa
30°C	50 MPa	80 MPa	85 MPa	90 MPa	100 MPa	115 MPa	125 MPa	125 MPa
40°C	65 MPa	90 MPa	95 MPa	100 MPa	105 MPa	125 MPa	125 MPa	125 MPa

At 7 days, the product achieves 92 MPa and maintains 92 MPa at 7 days when cured underwater at 15°C, demonstrating consistent high strength performance across various temperature conditions.

Additional Mechanical Properties

• Indirect Tensile Strength: 15 MPa at 7 days
• Flexural Strength (Modulus of Rupture): 29 MPa at 7 days
• Modulus of Elasticity: 13.5 GPa
• Thermal Coefficient of Expansion: 9.22 x 10⁻⁵ mm/mm °C
• Slant Shear Bond Strength: 36.7 MPa (substrate failure)
• Cured Density: 1840 kg/m³

Chemical Resistance

Conbextra EP65 Plus exhibits excellent chemical resistance to:

• Oil, grease, and fats
• Most common chemical spills
• Mild acids and alkalis
• Fresh and sea water
• Withstands a wide range of chemical spills

Users should consult Fosroc when exposure to solvents or concentrated chemicals is anticipated.

Pot Life and Working Time

Pot life is temperature-dependent and critical for application planning:

Ambient Temperature	Pot Life
10°C	60 minutes
15°C	45 minutes
20°C	30 minutes
30°C	15 minutes

Note: Where ambient temperatures exceed 20°C, the pot life will be reduced, requiring immediate placement after mixing.

Temperature Performance

Application Temperature Range

• Grouting may be carried out without conditioning at ambient temperatures from 5°C to 25°C
• Application should not proceed if ambient or surface temperature is <5°C and falling

Service Temperature Range

The cured grout is:

• Completely resistant to frost and sub-zero temperatures
• Suitable for use up to 55°C in service
• Maintains performance across wide temperature ranges

Flow Characteristics

The maximum distance of flow is governed by gap thickness, hydrostatic head applied, and ambient temperature:

Temperature	Gap Thickness	Hydrostatic Head	Maximum Flow
5°C	10mm	100mm	600mm
5°C	35mm	100mm	700mm
20°C	10mm	100mm	750mm
20°C	35mm	100mm	2000mm
30°C	10mm	100mm	950mm
30°C	35mm	100mm	2500mm

Storage and Shelf Life

The components have defined shelf lives when stored in dry, cool conditions in original unopened packs:

• Base Component: 24 months from date of manufacture
• Hardener Component: 36 months from date of manufacture

Applications

Primary Uses

Conbextra EP65 Plus is designed for use in:

• Grouting under baseplates, crane rails, and turbines where heavy dynamic loads are encountered
• Reciprocating machinery
• High speed turbines
• Centrifuges and drop forges
• Heavy crane and transporter rails
• Anchoring of steel bars
• Electroplating and chemical plants
• Areas where chemical spillage may occur

Specialized Applications

• Underwater grouting work - suitable for water-immersed environments
• Repair of water-immersed concrete structures such as bridge piles and wharf piles
• Vertical anchoring applications including hold down bolts and vertical starter bars
• Chemical anchor applications with excellent chemical resistance

Standards Compliance

Conbextra EP65 Plus complies with:

• AS 4020-2018 - suitable for use in potable water
• AWQC Report 323631
• AS1478.2 2005 - for compressive strength testing
• AS1012.2 10-2000 - for indirect tensile strength
• AS1012.2.11-2000 - for flexural strength
• AS 1012.17-1997 - for modulus of elasticity
• ASTM C882/C882M:2012 - for slant shear bond strength

Mixing Instructions

Equipment and Procedure

• Pour all contents of the smaller hardener component (Part B - amber liquid) into the larger resin component (Part A - black)
• Mix thoroughly until an even grey colour is obtained
• Use a forced-action mixer (essential for proper mixing)
• Mix at slow speed of 400-500 RPM for 3 to 5 minutes
• Employ a suitably sized drum with a helical (spiral) mixing paddle fitted to a heavy-duty 1500W mixer

Alternative Mixing Method

For standard applications:

• Use a helical mixing paddle (120-140mm diameter)
• Fitted to a heavy-duty mixer (1600W)
• Operate at 350 to 400 RPM
• Mix for 2 to 3 minutes until uniform mix is obtained

Application Instructions

Surface Preparation

For maximum adhesion, substrate must be:

• Clean and free from any loose material
• Abraded or roughened preferably by mechanical means
• Sandblasting is recommended for optimum adhesion

Foundation Surface Requirements

• Free from oil, grease, free standing water, or loosely adherent material
• Concrete surfaces cut back to sound base
• All dust removed
• Bolt holes or fixing pockets blown clean of dirt or debris

Steel Surface Preparation

• Shot blasted free of rust, paint, and flaky mill scale

Formwork Requirements

• Constructed to be leakproof
• Formed with release agent coating (grease, wax, or plastic coating)
• Acts as bond breaker for smooth grout surface

Placement Procedure

• Place immediately after mixing to take full advantage of limited pot life
• Pour grout steadily from one side only to eliminate water entrapment
• Maintain continuous grout flow
• For underwater applications, use tremmie pipe to place grout at bottom and gradually withdraw as grout displaces water

Adding Aggregate (Optional)

• Up to 10kg of Conbextra Grout Aggregate per 14 litre kit
• Typical yield increase: approximately 4 litres per 10kg of aggregate added
• Caution: Air may be entrained when adding aggregate - allow mixed product to settle and expel air bubbles before placing
• Note: Aggregate addition reduces flow characteristics; not recommended if high flow performance is required

Equipment Cleaning

• Clean immediately after use with Fosroc Solvent 10 before hardening of epoxy
• Hardened material can only be removed mechanically

Health and Safety

A Safety Data Sheet (SDS) is available from the Fosroc website and must be read before use. In emergency situations, contact any Poisons Information Centre (phone 13 11 26 within Australia) or a doctor for advice.

Reference Documents

Users should also refer to:

• Conbextra Epoxy Grouts Application Guide - available from Fosroc website
• Conbextra EP65 Plus Underwater Application Technical Data Sheet - for underwater grouting applications
• Fosroc Epoxy Anchoring Application Guidelines - for vertical anchoring applications
• Compressive Strength Testing Guide for Epoxy Grouts - for testing procedures and variations

References

• [1] Fosroc_Conbextra_EP65_Plus_TDS.pdf
• [3] Fosroc_Conbextra_EP65_Plus_Underwater_TDS.pdf
• [7] Fosroc_Conbextra_Grout_Aggregate_TDS.pdf