About Fosroc Conbextra EPHT

Fosroc Conbextra EPHT is a purpose-built, solvent-free epoxy resin grout aimed at one demanding scenario that defeats most general-purpose grouts: holding precision-aligned, dynamically loaded machinery in place when the equipment and its foundation run hot. The Fosroc product page positions it for installations with continuous operating temperatures up to 160°C, where conventional cementitious and standard epoxy grouts lose stiffness, creep under sustained load, and allow baseplates to settle out of alignment. EPHT is supplied as a pre-packed system of resin base, hardener and a graded mineral aggregate filler, designed so that on-site batching gives reproducible, factory-controlled properties without guesswork on mix ratios. Once mixed it flows freely into the gap beneath a baseplate, fully encapsulating holding-down bolts and providing total bearing area contact between the equipment and the concrete foundation. The cured grout develops high early strength so plant can be re-commissioned with minimum downtime, and its formulation is built for low creep under both sustained load and elevated temperature, with high flexural strength and tenacious adhesion to the substrate so that dynamic and impact loads transfer cleanly into the foundation. EPHT also resists attack from a wide range of chemicals, acids and alkalis, which matters in the refinery, petrochemical, fertiliser and power environments where hot rotating equipment typically sits. For Indian contractors and consultants, EPHT fills a specific gap in the Conbextra range: the high-strength epoxy grades such as EP75 and EP120 are excellent at ambient and moderately warm conditions, but EPHT is the grade Fosroc nominates when the continuous service temperature climbs toward 160°C. It is not a structural repair mortar, a thin-bed adhesive, or a general bedding grout; it is a specialist anchoring and machinery-grouting product, and specifying it correctly depends on knowing the true operating temperature, the gap geometry and the dynamic loading the equipment imposes.

The technical insight

The defining engineering property of EPHT is its heat deflection behaviour, not just its room-temperature strength. Every thermoset epoxy has a glass transition temperature (Tg) above which the cured resin transitions from a rigid, glassy state to a softer, rubbery state where creep accelerates and load-bearing capacity falls. A standard epoxy grout might post a high ambient compressive strength yet begin to soften well below 100°C, which is why pouring an EP75 or EP120 under a baseplate that will run at 140-160°C risks long-term settlement and bolt relaxation. EPHT is formulated with a higher-temperature hardener and filler system so that its useful load-bearing range is extended to a continuous service temperature of 160°C, keeping creep low at the operating point rather than only when cold. The verified figures from the Fosroc India listing — roughly 110 MPa compressive strength and a 150-minute pot life at 20°C — tell the practical story: the long pot life is deliberate, because a fast-setting epoxy in a deep 120mm pour would generate a damaging exotherm and could crack or debond, whereas the extended working time lets heat dissipate during placement of large machinery beds. The graded aggregate filler does double duty here, both reducing the polymer fraction (and therefore peak exotherm and thermal movement) and bringing the grout’s coefficient of thermal expansion closer to that of steel and concrete, which limits differential movement and bond stress as the assembly heats and cools through service cycles.

Where it is used

• Grouting baseplates of pumps, compressors and turbines that operate at high continuous temperatures near hot process streams
• Anchoring and grouting of rotating equipment in refineries, petrochemical plants and fertiliser units where heat and chemical exposure coincide
• Foundations for fans, mills and ID/FD equipment around kilns, boilers and furnaces in cement and power plants
• Holding-down bolt pockets and bedding for hot-service machinery requiring resistance to dynamic and impact loads
• Equipment skids and structural steel bases subject to elevated temperature combined with acid or alkali spillage
• Re-grouting of existing high-temperature machinery beds during turnaround where rapid re-commissioning is required

Key advantages

• Engineered for continuous service temperatures up to 160°C, well beyond the range of standard epoxy or cementitious grouts
• High compressive strength (around 110 MPa) for heavy static and dynamic machinery loads
• Low creep under sustained load even at elevated temperature, protecting long-term alignment
• High flexural strength and strong adhesion to substrate for clean transfer of dynamic and impact loads
• Resists attack from a wide range of chemicals, acids and alkalis common in process plants
• Free-flowing, solvent-free formulation gives full bearing-area contact and total bolt encapsulation
• High early strength enables minimum downtime and early re-commissioning of plant
• Pre-weighed, factory-controlled three-pack system delivers reproducible site results

Limitations & considerations

• Specialist high-temperature grade — over-specified and uneconomical for ambient-temperature machinery where EP75 or EP120 suffice
• Epoxy chemistry means cure rate, pot life and flow are temperature-sensitive; cold-weather placement needs conditioning and warm-weather placement needs care to manage exotherm
• Not a structural concrete repair mortar, screed, or thin-bed adhesive — purpose-built only for grouting and anchoring
• Deep single-lift pours of large volumes generate exotherm; manufacturer pour-depth and layering guidance must be followed
• Higher material cost per kg than cementitious grouts such as Conbextra GP, justified only where the service temperature demands it
• Substrate must be clean, sound, dry and oil-free; contaminated or damp surfaces compromise the epoxy bond
• Requires trained applicators and correct full-pack mixing — partial-pack batching alters the resin-to-hardener-to-filler ratio and degrades performance

Selection & best practice

Specifications

Industry use cases

How we position Fosroc Conbextra EPHT

Within the Fosroc Conbextra family, EPHT is the high-temperature specialist of the epoxy grout line. It sits above the general-purpose cementitious grout Conbextra GP and the cementitious high-temperature grade Conbextra HT, and alongside the high-strength epoxy grades Conbextra EP75, EP120 and EP300 — but it is the grade to specify when continuous service temperature approaches 160°C, a point at which those ambient-rated epoxies are no longer appropriate. For most machinery grouting at normal temperatures, EP75 or EP120 are the right and more economical choice; EPHT is reserved for genuinely hot installations where its heat-stable, low-creep formulation is essential. Against competitors, credible alternatives in the Indian high-temperature epoxy grouting space include Sika’s epoxy grout range (such as SikaGrout-3000 series epoxy grades) and MBS/MYK, while general grouting needs may also be served by Dr. Fixit and STP cementitious systems; however, for the specific combination of 160°C continuous service, high dynamic-load capacity and chemical resistance, the dedicated high-temperature epoxy grades like EPHT are the targeted solution rather than the general-purpose products. Space Arc Engineering, as an authorised Fosroc distributor and applicator across Delhi NCR and Pan-India, helps consultants and contractors select between EPHT and the standard Conbextra epoxy grades based on verified service temperature and loading, and supplies both the material and the trained application support that high-temperature machinery grouting demands.

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