Conbextra EP300 DP: Low Exotherm Three Part Epoxy Resin Grout

Product Overview

Conbextra EP300 DP is a low exotherm three-part epoxy resin grout manufactured by Fosroc, specifically engineered for large volume pours and applications subjected to heavy dynamic or mobile loads. The product is supplied as an 11.4 litre pack containing all three necessary components: base resin, hardener, and filler material, making it a complete, ready-to-use system for specialized grouting applications.

Key Technical Specifications

Composition and Supply

The product consists of three distinct components:

• Base Component: FC500547-2.7L
• Hardener Component: FC500545-860ML
• Filler Component: FC500546-20KG

Design Gap Range

Conbextra EP300 DP is designed to be grouted into gaps ranging from 10mm up to 300mm. For grouting of gap widths below 50mm, curing will take longer due to the low exotherm nature of the grout. Grout pours greater than 300mm thick are possible, but the total volume of a single pour should not exceed 1.5 m³ depending on the geometry of the pour.

Mechanical Properties

The following properties were measured at 23°C according to established standards:

Property	Standard	1 Day	3 Days	7 Days	28 Days
Compressive Strength (MPa)	AS 1478.2:2005	65	75	85	90

Additional Properties:

• Mixed Density: 2069 kg/m³
• Peak Exotherm: 30°C (50mm x 100mm cylinder)
• Linear Shrinkage: -0.017% (ASTM C531)
• Volume Change: -0.419% (ASTM C827)
• Modulus of Elasticity: 16 GPa (AS 1012.17-1997)
• Indirect Tensile Strength: 14 MPa @ 28 days (AS 1012.2 10-2000)
• Flexural Strength (Modulus of Rupture): 33 MPa @ 28 days (AS 1012.2 11-2000)
• Thermal Coefficient of Expansion: 2.34 x 10⁻⁵ mm/mm °C (ASTM C531)
• Bond Strength: Concrete Failure (ASTM C882/C882M:2012)
• Creep @ 28 days (2.8 MPa): 4.47 x 10⁻³ cm/cm @ 60°C (ASTM C1181-00)
• Chloride Content: 0.0% (EN 1015-17:2000)
• Colour: Charcoal grey (mixed)
• Minimum Thickness: 10mm
• Maximum Thickness: 300mm
• Maximum Aggregate Size (for pumping): 2mm

Pot Life

The working time varies with ambient temperature:

Temperature	Pot Life
10°C	6 hours
20°C	3 hours
30°C	1.5 hours

Advantages and Performance Characteristics

Conbextra EP300 DP offers multiple benefits for demanding applications:

• High Compressive, Tensile and Flexural Strengths: Provides robust structural performance
• Resistant to Repetitive Dynamic Loads: Suitable for machinery and equipment subjected to continuous motion
• Fast, Convenient Installation: Streamlined application procedures
• Wide Chemical Resistance: Withstands oil, grease, fats, most chemicals, mild acids and alkalis, fresh and sea water
• Virtually No Shrinkage: Ensures complete surface contact and bond between grout and base plate
• Low Creep Characteristics: Maintains performance under sustained loading
• Excellent Flow Properties: Provides superior flow distribution in formwork
• High Temperature Installation: Can be used installed at high temperatures
• Wide Gap Range: Accommodates various gap thicknesses from 10mm to 300mm
• Low Exotherm: Minimizes heat generation during curing, reducing thermal stress and potential cracking

Flow Characteristics

The maximum distance of grout flow is governed by three critical factors:

• Gap thickness
• Head of grout applied
• Ambient temperature

At 23°C with a 100mm gap thickness and 100mm hydrostatic head, the maximum flow distance is 2000mm. Flow test results (AS 1478.2) show a flow of 500mm.

Chemical Resistance

Conbextra EP300 DP demonstrates resistance to:

• Oil, grease, and fats
• Most common chemicals
• Mild acids and alkalis
• Fresh and sea water

Note: Fosroc should be consulted when exposure to solvents or concentrated chemicals is anticipated.

Applications

Conbextra EP300 DP is particularly well-suited for:

• Reciprocating machinery
• Testing equipment
• Heavy crane and transporter rails
• High speed turbines
• Centrifuges and drop forges
• Chemical plant applications (steelworks, refineries, electroplating works)
• Piletop encapsulation: Ensures water tightness and prevents water seepage through capillaries or along reinforcement paths
• Applications with chemical spillage exposure

Storage and Shelf Life

• Base and Hardener Components: 5 years shelf life from date of manufacture
• Filler Component: 18 months shelf life from date of manufacture when kept in original, unopened bags

Both components must be stored in dry conditions within original, unopened packaging.

Temperature Performance

During Application

Grouting may be carried out without special precautions at ambient temperatures from 5°C to 35°C. Where temperatures exceed 20°C, the pot life will be reduced.

Important: Cure temperatures below 15°C will result in slower strength build up; at 5°C, cure will stop until the material warms.

In Service

When Conbextra EP300 DP is fully cured, it is completely resistant to:

• Frost and sub-zero temperatures
• Temperatures as high as 55°C

Exotherm Development

All epoxy systems develop a temperature rise on mixing. The extent is a function of:

• Volume to surface ratio
• Ambient temperature
• Mass and thermal conductivity of surrounding materials

The low exotherm formulation of Conbextra EP300 DP is particularly advantageous for large volume pours, as it minimizes heat generation during the curing process, reducing the risk of thermal stress and potential cracking.

Dimensional Stability

For the grout to effectively transfer load from the base plate to the supporting structure, maintaining intimate contact with the base plate is essential. The area of contact is measured as the 'effective bearing area' (EBA).

A dominant factor influencing the EBA achieved with epoxy-based grouts is the degree of air entrapment within the product. Air can be introduced during mixing, or in products with separate dry filler components, air can be released as the filler wets out over time.

Storage Conditions

Components must be stored in dry conditions within original, unopened packs to maintain product integrity and performance characteristics throughout their shelf lives.

References

• [1] Fosroc_Conbextra_EP300_DP_TDS.pdf