About Fosroc Conbextra EBG(M)

Conbextra EBG(M) is Fosroc’s dedicated bearing-bed grout — a two-component epoxy supplied with the resin base and hardener factory-weighed in matched packs, so site crews mix complete units rather than judging proportions by eye. Unlike the free-flowing precision grouts most engineers picture when they hear “Conbextra”, EBG(M) is deliberately thixotropic: it holds as a stiff, trowelable paste on the pedestal instead of running off. That matters because the few centimetres of grout beneath a bearing carry the entire girder reaction for the life of the structure. The formulation therefore prioritises high compressive strength, bond and long-term creep control over flow, and it is proven in bed thicknesses from just 3 mm up to 50 mm — a band where placing and compacting a cementitious grout reliably is genuinely difficult.

With India’s highway, expressway and metro programmes now carrying a steady pipeline of both new bearing installations and jack-and-replace rehabilitation of older ones, demand for a purpose-made bearing grout has grown well beyond the odd speciality order. Space Arc Engineering supplies Conbextra EBG(M) as an authorised Fosroc distributor and applicator, serving Delhi NCR and project sites pan-India. We help consultants match the grout to the bearing type and gap, and our application teams can take on the bedding work itself where the contractor prefers a single point of responsibility.

The technical insight

Two properties do the real work in this product. The first is thixotropy: under the shear of mixing and trowelling the paste loosens enough to butter and wet out the surfaces, but the moment it comes to rest it stiffens and holds its shape — which is why it can sit on an exposed pedestal, a stepped seat or an inclined face without shuttering. The second is the epoxy binder itself. In a 3–10 mm bed, a cementitious grout loses mix water to the substrate and risks bleed, settlement and plastic shrinkage; a cross-linked epoxy cures by reaction, not drying, so the thin bed stays dense and in full contact. Because a bearing bed sees sustained stress rather than brief peaks, Fosroc assesses the material’s compressive creep to ASTM C1181 — the recognised test for polymer bearing and machinery grouts — confirming the bed will not slowly squeeze down and unload the bearing over time.

Where it is used

• Bedding elastomeric and POT-PTFE bearings on pedestals of flyovers, ROBs and metro viaducts
• Grouting beneath girder seats and bearing plates where the gap runs between 3 mm and 50 mm
• Re-bedding bearings during jack-and-replace rehabilitation of in-service bridges
• Seating structural steel base plates where shuttering for a flowable grout is impractical
• Rail plate and sole plate grouting on transport and plant structures
• Thin, high-contact-stress packing beneath machinery sole plates
• Bedding on stepped or inclined seats where a free-flow grout would drain away before curing

Key advantages

• Non-slump thixotropic body applies by trowel on horizontal, stepped or inclined seats — no formwork or grout dams
• Pre-weighed two-pack supply removes site-proportioning errors; mixing full packs gives repeatable quality every batch
• Compressive strength in the 60 N/mm² class carries concentrated bearing reactions even in very thin beds
• Compressive-creep behaviour assessed to ASTM C1181, the governing test for polymer bearing and machinery grouts
• Cures by chemical reaction without shrinkage, maintaining positive full-face contact under the bearing plate
• Reliable in narrow 3–50 mm gaps where compacting a cementitious grout is hit-and-miss
• Bonds strongly to correctly prepared concrete and steel, resisting bearing walk and traffic vibration

Limitations & considerations

• It is thixotropic, not free-flowing — it cannot be poured or pumped under large, congested base plates; use a free-flow epoxy grout such as Conbextra EP75 there
• Bed thickness is limited to roughly 3–50 mm; deeper pockets call for a flowable precision grout placed in controlled lifts
• Working time shortens sharply in hot Indian site conditions — mix only what can be placed promptly and keep packs shaded in summer
• Thermal expansion of epoxy is higher than that of concrete, so large exposed beds need detailing for temperature movement
• Performance depends entirely on preparation — laitance, curing compound, oil or standing water on the seat will compromise the bond
• Costs more per litre than cementitious bearing grouts, so reserve it for beds where epoxy performance is genuinely required

Selection & best practice

Specifications

Industry use cases

How we position Fosroc Conbextra EBG(M)

Within the Fosroc grout family, Conbextra EBG(M) is the thixotropic bearing specialist — pick it when the bed is thin, unshuttered and permanently loaded. For routine cementitious bridge-bearing bedding at lower cost, look at Conbextra BB; for free-flow epoxy grouting under machinery and congested baseplates, Conbextra EP75; for general non-shrink precision grouting of columns and equipment, Conbextra GP2; and for low-viscosity crack injection, Conbextra EP10. Space Arc stocks the full Conbextra range from Delhi NCR with pan-India dispatch, and where a project has standardised on another system our team can propose equivalent grouting options from the other manufacturers we distribute.

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