Fosroc Conbextra EP120
A solvent-free, low-exotherm two-part epoxy grout engineered for heavy dynamic and impact loads, large-volume pours and chemically aggressive environments — gap widths from 10 mm to 120 mm.
What is it?
A solvent-free, two-part (base + hardener) epoxy resin grout that flows into gaps of 10-120 mm without any site-added aggregate, delivering high compressive, tensile and flexural strength with very low shrinkage.
Where is it used?
Under reciprocating and rotating machinery, turbine and compressor base plates, crane and transporter rails, drop forges, centrifuges and in chemical-spillage zones at steel works, refineries, power plants and process industries.
Why use it?
It resists repetitive dynamic and impact loads, creeps very little under sustained load, withstands oils and a wide range of chemicals, and its low-exotherm formulation suits large pours and high Indian ambient temperatures.
How is it applied?
Surfaces are prepared, formwork sealed, the full hardener pack is mixed into the base with a slow-speed forced-action mixer, then the grout is poured continuously from one side to displace air and fill the gap.
About Fosroc Conbextra EP120
Fosroc Conbextra EP120 is a high-performance, solvent-free epoxy resin grout supplied as a pre-weighed two-part system — a charcoal-grey base and a liquid hardener. Unlike a cementitious grout, it is a fully reactive epoxy that bonds tenaciously to clean concrete and steel and develops strength through chemical cure rather than hydration, so it is unaffected by the drying-shrinkage and bleed problems that affect cement-based products. A defining feature is that no aggregate has to be added on site: the formulation is supplied ready to mix, which removes a common source of batch-to-batch variability and speeds up placement. Conbextra EP120 is positioned within Fosroc’s epoxy grouting range as the long-working-time, low-exotherm option for the most demanding situations — heavy dynamic and impact loads, large single pours and wide gaps. Where a fast-setting epoxy is needed for thin sections, Fosroc’s own literature points users to Conbextra EP65 Plus instead; where the duty is static and modest, the cementitious Conbextra GP or HF grouts are usually more economical. EP120 earns its place when the base plate sees vibration, reciprocation or shock, or when the gap is too deep for a normal epoxy to dissipate heat safely. It is designed to be grouted into gaps from 10 mm up to 120 mm, and pours thicker than 120 mm are possible provided a single pour does not exceed roughly 1 cubic metre. For contractors and consultants in India, it is the grout specified when machinery alignment must be held for the life of the asset under conditions that would loosen or fatigue a lesser bedding material.
The technical insight
The engineering value of Conbextra EP120 lies in three linked properties: low creep, low exotherm and high dynamic-load resistance. Epoxy grouts can creep under permanently loaded bolts, slowly relaxing the preload that keeps a machine aligned; EP120 is formulated for low creep under sustained loading, which is why it is favoured for precision rotating equipment. Equally important is its low exotherm. All epoxies generate heat as they cure, and in a deep pour that heat can build up, causing thermal cracking or accelerated, uneven cure — EP120’s chemistry releases that heat slowly, which is precisely what allows pours up to 120 mm and large volumes that would be unsafe with a fast-reacting epoxy. The trade-off is honest and stated in the datasheet: gap widths below 50 mm take longer to cure because there is less mass to drive the exotherm, so for thin, fast-turnaround sections EP65 Plus is the better tool. The cured grout reaches a compressive strength of around 80 MPa at 28 days (cube samples, 23°C), with indirect tensile strength near 10 MPa and flexural strength near 25 MPa — comfortably exceeding the strength of the concrete foundation it sits on, so any failure plane stays in the substrate rather than the grout. A modulus of elasticity of about 8.4 GPa keeps the grout stiff enough to transmit load yet able to accommodate minor movement, and a slant-shear bond strength of 22.3 MPa (with failure occurring in the concrete) confirms the bond is stronger than the parent material.
Where it is used
- Grouting base plates of reciprocating machinery, compressors and pumps subject to vibration
- Bedding high-speed turbine, generator and centrifuge foundations requiring sustained alignment
- Anchoring drop forges, presses and impact equipment that transmit shock to the foundation
- Setting heavy crane rails, transporter rails and gantry tracks under repetitive moving loads
- Large-volume and deep pours (up to 120 mm, single pour up to ~1 m³) where low exotherm is essential
- Grouting in chemical-spillage zones at refineries, steel works, electroplating shops and chemical plants
- Machinery installation in high ambient temperatures where a long working time is needed
Key advantages
- High compressive, tensile and flexural strength that exceeds typical foundation concrete
- Virtually no shrinkage, ensuring full contact and effective bearing area under the base plate
- Resistant to repetitive dynamic, vibratory and impact loading without fatigue cracking
- Low creep under sustained bolt preload, helping machinery hold alignment long-term
- Low-exotherm formulation permits deep pours up to 120 mm and large single volumes
- Supplied as a pre-weighed two-part pack with no site-added aggregate, improving quality control
- Excellent flow into restricted gaps and around bolt pockets
- Broad chemical resistance to oils, greases, fats, mild acids and alkalis, fresh and sea water
- Effectively zero chloride content, suitable near embedded steel and reinforcement
Limitations & considerations
- Slower cure at gap widths below 50 mm due to reduced exotherm — use Conbextra EP65 Plus for fast thin-section work
- Single pours should not exceed roughly 1 m³, and pours over 120 mm need consultation with Fosroc
- Higher material cost than cementitious grouts such as Conbextra GP, so it is over-specification for light static loads
- Pot life shortens sharply with temperature (about 1.5 hours at 30°C), demanding disciplined batching and placement in Indian summer conditions
- Requires a forced-action / slow-speed mechanical mixer; hand mixing is not acceptable
- A two-component epoxy that must be used at full pack ratio — partial mixing risks incomplete cure
- Surfaces must be clean, dry and free of oil and laitance, or bond will be compromised
- Consult Fosroc Technical Services before exposure to solvents or concentrated chemicals
Selection & best practice
Plan the pour around temperature: in Delhi NCR summers the pot life can drop to about 1.5 hours at 30°C, so stage the base, hardener, mixer and labour before opening any pack, and pour continuously from one side to push air out and avoid voids. Cut concrete back to a sound, dust-free base, remove all oil, grease and free water, and pre-fill bolt pockets first. Mix the entire hardener pack into the base — never a partial ratio — using a slow-speed forced-action mixer for 3 to 5 minutes, and head-pour from a single side using a hopper or sloped formwork to keep the flow front moving. Seal formwork tightly and leave a working head to maintain pressure during cure. For gaps below 50 mm where a fast turnaround matters, switch to Conbextra EP65 Plus rather than forcing EP120; for static, lightly loaded plant, a cementitious grout is more economical. Always work to the current Fosroc TDS and method statement for the destination country and confirm pack and standard details with us for your specific project.
Specifications
| Chemical type / system | Solvent-free two-part epoxy resin grout (base + hardener); no site-added aggregate |
| Colour (mixed) | Charcoal grey |
| Gap width range | 10 mm (min) to 120 mm (max); single pour up to ~1 m³ |
| Density | 1700 kg/m³ |
| Compressive strength (cube, 23°C) | ~6 MPa (1 day), ~45 MPa (3 days), ~75 MPa (7 days), ~80 MPa (28 days), ~85 MPa (56 days) |
| Indirect tensile strength (28 days) | 10 MPa |
| Flexural strength / modulus of rupture (28 days) | 25 MPa |
| Modulus of elasticity | 8.4 GPa |
| Slant shear bond strength | 22.3 MPa (failure in concrete) — ASTM C882 |
| Thermal coefficient of expansion | 1.06 x 10⁻⁴ mm/mm°C (ASTM C531) |
| Chloride content | 0.0% (EN 1015-17) |
| Pot life | ~6 hours at 10°C, ~3 hours at 20°C, ~1.5 hours at 30°C |
| Maximum service temperature | Up to 55°C |
| Pack size | 14 litre two-component pack (Base 11.3 L + Hardener 2.7 L) |
| Shelf life | 12 months from manufacture in unopened packs, stored cool and dry |
| Mixing | Slow-speed (400-500 rpm) forced-action mechanical mixer, 3-5 minutes |
Industry use cases
Power generation
Bedding steam and gas turbine, generator and large pump base plates where sustained alignment under continuous vibration is critical, and where deep low-exotherm pours are required.
Steel & heavy industry
Grouting drop forges, presses, rolling-mill and transporter-rail foundations subject to impact and repetitive dynamic loads, often in oil- and chemical-contaminated environments.
Oil, gas & refineries
Anchoring reciprocating compressors and rotating equipment in process plants where the grout must resist hydrocarbons, mild acids and alkalis as well as dynamic loading.
Cement & process plants
Setting heavy crushers, mills, centrifuges and conveyor drives on large foundations, using the low-exotherm profile to place big volumes safely in hot Indian conditions.
Material handling & ports
Fixing crane rails, gantry tracks and transporter rails carrying repetitive moving loads where shrinkage and creep would otherwise loosen the bedding over time.
Frequently asked questions
Is Conbextra EP120 an epoxy or a cementitious grout?
What gap widths and pour depths can Conbextra EP120 handle?
What compressive strength does it reach?
How long is the working time, and does heat affect it?
When should I choose EP120 over Conbextra EP65 Plus or a cementitious grout?
Can Space Arc Engineering supply EP120 across India?
How we position Fosroc Conbextra EP120
Within the Fosroc Conbextra family, EP120 is the premium epoxy grout reserved for dynamic, impact and chemically aggressive duty, and for deep or large-volume pours where its low-exotherm chemistry is the deciding factor. It sits above the general-purpose cementitious grouts Conbextra GP and the high-flow/high-strength Conbextra HF and HS, which remain the right, more economical choice for static or lightly loaded base plates. For thin sections needing a fast cure, Fosroc’s own EP65 Plus is the recommended sibling product, and for precision machinery the Conbextra EP epoxy range overlaps with Fosroc’s Nitomortar epoxy mortars and Nitobond bonding agents on adjacent jobs. Against the wider Indian market, credible alternatives in the epoxy-grout class include Sika’s SikaGrout epoxy systems and Sikadur range, MBS (MYK) epoxy grouts, Dr. Fixit’s epoxy grouting solutions and STP’s epoxy grout offerings; in cementitious territory the comparison broadens to Sika and Dr. Fixit non-shrink grouts. EP120 differentiates on its combination of low creep, low exotherm, broad chemical resistance and proven dynamic-load performance backed by Fosroc’s documented test data. As an authorised Fosroc distributor and applicator across Delhi NCR and Pan-India, Space Arc Engineering can help specifiers confirm that EP120 is the correct grade for the load case — or recommend the more cost-effective Conbextra option where the duty does not justify a high-performance epoxy.
Related Grouts & Anchors products
Source Fosroc Conbextra EP120 for your project
Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.