Fosroc Conbextra EP40
Free-flowing, solvent-free epoxy resin grout for precision baseplate and underplate grouting under heavy dynamic and chemically aggressive loads.
What is it?
A two-component, solvent-free epoxy resin grout (resin base + hardener) that flows freely into gaps of roughly 5 to 40 mm, curing to a high-strength, non-shrink, chemically resistant load-transfer medium.
Where is it used?
Under machinery baseplates, crane and transporter rails, turbines, centrifuges and forging equipment, and in steel plants, refineries, electroplating and chemical works across industrial and infrastructure projects in India.
Why use it?
It carries repetitive dynamic and impact loads that crack ordinary cementitious grouts, resists oils and chemicals, and maintains intimate baseplate contact (high effective bearing area) for uniform load distribution.
How is it applied?
Whole-pack mix the hardener into the base for ~3 minutes, then pour from one side with a hydrostatic head/feeding hopper into leak-proof formwork; place within pot life and allow to cure.
About Fosroc Conbextra EP40
Fosroc Conbextra EP40 is a free-flowing, solvent-free epoxy resin grout engineered for precision grouting of gaps between approximately 5 mm and 40 mm. Supplied as a pre-weighed two-component system (an epoxy resin base blended with graded inert fillers, plus a hardener), it is whole-pack mixed on site to deliver a fluid, self-levelling grout that fully fills the void beneath a baseplate and cures to a dense, high-strength solid. It sits in the middle of Fosroc’s Conbextra epoxy family, above the thin-gap Conbextra EP10/EP10(M) and below ultra-high-strength grades such as Conbextra EP75, and is positioned specifically where a moderate 10-40 mm gap must transmit demanding loads. Because the cured grout is non-shrink, it stays in intimate contact with the underside of the plate, achieving the high “effective bearing area” (EBA) that is essential for transferring load uniformly into the foundation. For Indian contractors, consultants and plant engineers, EP40 is the product reached for when a cementitious grout simply will not survive the service conditions, vibration, repetitive dynamic loading, impact, or contact with oils, fuels, mild acids and alkalis. It is widely specified for rotating and reciprocating machinery, heavy crane and transporter rails, and equipment in steelworks, refineries, electroplating works and chemical plants. Space Arc Engineering supplies and applies Conbextra EP40 across Delhi NCR and Pan-India as an authorised Fosroc distributor and applicator, supporting projects from foundation design review through to site placement.
The technical insight
EP40’s value comes from how it behaves under sustained and cyclic load rather than from peak strength alone. The cured grout develops a 7-day compressive strength in the order of 75-90 N/mm2 (higher at elevated cure temperatures), an indirect tensile strength around 15 N/mm2 and a flexural (modulus of rupture) strength near 30 N/mm2, giving it the tensile and flexural capacity that brittle cementitious grouts lack under impact and vibration. Crucially, the formulation is engineered for low creep under sustained loading, so a precisely shimmed baseplate stays in position over years of service instead of slowly settling. Bond performance is strong: pull-off bond is around 2.9 N/mm2, bond to steel about 14 N/mm2, and bond to sound concrete typically exceeds the concrete’s own tensile strength (failure occurs in the substrate, not the grout line). The mixed density is roughly 1950 kg/m3, so yield per pack is lower by volume than a cementitious grout of the same mass, this must be factored into ordering. Pot life is the main site-management constraint: it is temperature-driven and falls sharply as ambient rises, so in Indian summer conditions placement windows shrink and pre-planning of mixing and pouring sequence is essential. Reported chloride content is effectively nil, which matters for grouting near reinforcement or embedded steel.
Where it is used
- Underplate and baseplate grouting of reciprocating and rotating machinery subject to dynamic loads
- Grouting under high-speed turbines, centrifuges, compressors and pumps
- Bedding of heavy crane rails, transporter rails and gantry tracks
- Grouting of drop forges, presses and impact-loaded testing equipment
- Machine and equipment foundations in steelworks, refineries and chemical plants
- Anchoring and grouting where chemical spillage (oils, fuels, mild acids/alkalis) is likely
- Precision load-transfer grouting where 10-40 mm gaps demand high strength and low creep
Key advantages
- High compressive, tensile and flexural strength for demanding load transfer
- Excellent resistance to repetitive dynamic, vibratory and impact loading
- Low creep under sustained load keeps precisely set baseplates in position
- Non-shrink, so it maintains a high effective bearing area and full plate contact
- Resists oils, greases, fuels, mild acids and alkalis, fresh and sea water
- Solvent-free with effectively zero chloride content, suitable near embedded steel
- Pre-weighed whole-pack components remove site batching errors
- Free-flowing and self-levelling for thorough filling of confined voids
Limitations & considerations
- Pot life is short and temperature-sensitive (drops to ~15 min at 30 C), demanding tight pour planning in Indian summer
- Higher unit cost than cementitious grouts; reserved for genuinely demanding applications
- Should not be placed unrestrained (open plinths/edges) or excessively thick in one pour without guidance, due to exotherm and creep risk
- Cure slows below ~15 C and effectively stops near 5 C; not for cold placement without precautions
- Continuous chemical strength generally rated to about 45 C service temperature
- Higher mixed density (~1950 kg/m3) means lower volumetric yield per pack than cementitious grout
- Epoxy resins can sensitise skin; gloves, barrier cream and eye protection are required
- Substrate, steel and formwork must be scrupulously clean, dry and leak-proof for full performance
Selection & best practice
Confirm the gap falls in the 10-40 mm sweet spot, then prepare meticulously: cut concrete back to a sound base, blow bolt pockets clean, shot-blast steel to bright metal, and build leak-proof formwork with a feeding hopper to maintain hydrostatic head. Pour from one side only to expel air and keep a continuous grout front. Because pot life can be as low as 15 minutes at 30 C, in Indian conditions store components in shade, schedule pours for cooler parts of the day, stage enough labour to place each batch within pot life, and never re-temper stiffened material. Order against the ~1950 kg/m3 mixed density and 15-litre pack format, allowing wastage, and place only when all surfaces are dry. For thick or large pours, or any unrestrained edge, consult the Fosroc/Space Arc technical team before proceeding.
Specifications
| Product type | Two-component, solvent-free epoxy resin grout |
| Gap / layer thickness | Approx. 5 to 40 mm (10-40 mm optimal free-flow range) |
| Mixed density | Approx. 1950 kg/m3 |
| Compressive strength (7 days) | Approx. 75 N/mm2 at 23 C; up to ~90-91 N/mm2 at elevated cure temperature (AS1478.2) |
| Compressive strength (1 day) | Approx. 79 N/mm2 at 20 C |
| Indirect tensile strength (7 days) | Approx. 15 N/mm2 (AS1012.2) |
| Flexural strength / modulus of rupture (7 days) | Approx. 30 N/mm2 (AS1012.2.11) |
| Bond strength (pull-off) | Approx. 2.9 N/mm2 (EN1542); to steel ~14 N/mm2; to concrete = substrate failure |
| Pot life | Approx. 100 min at 20 C (UK data); ~60 min at 10 C / ~30 min at 20 C / ~15 min at 30 C per licensed TDS |
| Chloride content | 0.0% (EN1015-17) |
| Max service temperature | Approx. 45 C (continuous) |
| Pack size | 15 litre two-component pack (base + hardener) |
| Shelf life | 12 months in dry conditions at ~20 C |
Industry use cases
Power & Heavy Engineering
Grouting under turbine, compressor and generator baseplates where high-speed rotation creates continuous vibration that would crack cementitious grout.
Steel Plants & Foundries
Bedding drop forges, presses and impact-loaded equipment, and crane/transporter rails subject to repetitive shock loading.
Refineries & Chemical Plants
Anchoring and grouting pump and machinery bases where oil, fuel and mild chemical spillage demand a resistant, non-absorbent grout.
Ports, Cranes & Material Handling
Precision bedding of gantry crane and transporter rails where alignment must hold under heavy, moving wheel loads.
Manufacturing & Automotive
Grouting reciprocating machinery, presses and testing rigs requiring low-creep, dynamically stable load transfer.
Frequently asked questions
Is Conbextra EP40 a cementitious or an epoxy grout?
What gap thickness can Conbextra EP40 fill?
How much working time (pot life) does it have on site in India?
What is the compressive strength of Conbextra EP40?
How do I estimate quantity and what pack size does it come in?
Does Space Arc supply and apply Conbextra EP40 across India?
How we position Fosroc Conbextra EP40
Within the Fosroc range, Conbextra EP40 is the mid-gap epoxy workhorse: step down to Conbextra EP10 or EP10(M) for thin (sub-10 mm) injection and gap grouting, and step up to Conbextra EP75 (or the consolidated EP65-class grouts that have superseded EP40 in some markets) when ultra-high strength or larger sections are required. Where conditions are static and loads are conventional, a cementitious non-shrink grout such as Conbextra GP2 or GP3 is usually more economical and is the right call, EP40 should be reserved for genuinely dynamic, impact or chemically aggressive duty. It also pairs naturally with Fosroc ancillaries like Nitoprime 25 for steel protection. Against the wider Indian market, credible epoxy-grout alternatives include Sika’s SikaGrout epoxy grades, MYK MBS (formerly MBS/Mc-Bauchemie) epoxy grouts, STP and Dr. Fixit/Pidilite system products; specifiers typically choose on verified TDS values, dynamic-load track record, local technical support and availability. Space Arc Engineering’s role is to match the correct grade to the actual gap, load and exposure, supply genuine Fosroc material, and back it with applicator support across Delhi NCR and Pan-India.
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