Fosroc Conbextra GV08
A free-flow, non-shrink cementitious grout engineered for thick-section pours over 70mm where low heat build-up and self-levelling placement matter most.
What is it?
A single-pack, ready-to-use non-shrink cementitious grout supplied as a dry powder, formulated specifically for large gap thicknesses over 70mm. It mixes with water to a free-flowing, self-levelling consistency and sets without shrinkage.
Where is it used?
Beneath heavy machine baseplates, bridge bearings, crane rails, turbine and compressor foundations, and any deep-section grouting where conventional precision grouts would generate excessive heat or cracking.
Why use it?
Its low exothermicity controls the heat of hydration in thick sections, preventing thermal cracking, while non-shrink behaviour and high early strength deliver full, durable contact under the load-bearing plate.
How is it applied?
Mixed with measured water in a forced-action mixer to a flowable consistency, then poured or pumped continuously from one side into the formed gap so it self-levels and fully fills the void without trapped air.
About Fosroc Conbextra GV08
Fosroc Conbextra GV08 belongs to the Conbextra family of cementitious grouts, the long-established workhorse range used across Indian infrastructure and heavy industry for filling the gap between a structure and the steel or equipment it supports. Where standard precision grouts such as Conbextra GP2 are designed for thin, tight pours, GV08 is purpose-built for the opposite challenge: large gap thicknesses over 70mm in a single placement. Pouring a deep section of ordinary high-strength grout in one lift generates a large volume of heat as the cement hydrates, and that heat can drive thermal stresses, micro-cracking and dimensional movement exactly where you need a stable, fully bonded load path. GV08 is engineered around a low-exothermicity binder system that keeps the internal temperature rise under control even in thick pours, so the grout can be placed in deeper lifts without the cracking risk that limits conventional products. It arrives as a factory-blended dry powder, which removes site batching errors: the contractor simply adds clean water in the specified proportion, mixes, and places. The result is a free-flowing, self-levelling material that fills irregular voids, flows around anchor bolts and pockets, and cures to a hard, non-shrink mass in full contact with both the foundation and the underside of the bearing plate. For specifiers in India, GV08 is the answer to a recurring problem on bridges, plant foundations and crane gantries, where bearing gaps and baseplate clearances routinely exceed what a normal grout is rated to handle in one pour. Space Arc Engineering supplies and applies GV08 as an authorised Fosroc distributor and applicator across Delhi NCR and on projects Pan-India, pairing the material with site method statements so the low-heat advantage is actually realised in the field rather than lost to poor mixing or placement.
The technical insight
The defining engineering property of Conbextra GV08 is low exothermicity, and understanding why it matters is central to specifying it correctly. Every cementitious grout releases heat as the binder hydrates; in a thin pour that heat dissipates harmlessly, but in a section over 70mm the core of the grout can reach a markedly higher temperature than its surface and the surrounding steel. As the hot core later cools and contracts against already-set outer material, tensile stresses build that ordinary grouts cannot accommodate, producing cracks that compromise the very load transfer the grout exists to provide. GV08’s binder chemistry is balanced to lower peak hydration temperature and flatten the temperature gradient, so a deep lift behaves predictably. This is paired with non-shrink behaviour: the formulation compensates for the natural plastic and drying shrinkage of cement so the cured grout stays in intimate, gap-free contact with the baseplate above and the foundation below. The third pillar is fluidity. GV08 is designed to be genuinely free-flowing and self-levelling at a controlled water content, which is what lets it travel under a large plate and around bolt pockets from a single pour point without vibration and without leaving voids. High early strength rounds out the profile, letting equipment be commissioned sooner. Because it is chloride-free, GV08 is safe in contact with embedded steel and post-tensioning hardware, an important consideration for bridge bearings and reinforced foundations. The trade-off the designer must respect is that these properties are only delivered within the specified water dosage and a minimum section of 70mm or more; thinning the mix to chase flow, or using GV08 in shallow gaps it was not designed for, undermines both the strength and the low-heat benefit.
Where it is used
- Heavy-duty grouting beneath machine baseplates and equipment skids with deep clearances
- Bridge bearing seating and pedestal grouting where bearing gaps exceed 70mm
- Crane rail and gantry baseplate grouting subject to dynamic and impact loads
- Turbine, compressor, generator and large pump foundation grouting in power and process plants
- Deep-section structural infill and pocket grouting for precast column connections and bolt boxes
- Anchor bolt and holding-down bolt grouting in thick stanchion bases
- Reinstatement of large voids and recesses under load-bearing plates
Key advantages
- Low exothermicity allows deep single-lift pours over 70mm without the thermal cracking risk of conventional grouts
- Non-shrink behaviour maintains full, gap-free contact between foundation and baseplate for reliable load transfer
- Free-flowing and self-levelling, so it fills irregular voids and flows around bolts from one pour point without vibration
- High early strength eases installation and shortens the time to equipment commissioning
- Chloride-free formulation is safe against embedded reinforcement, anchor bolts and post-tensioning steel
- Supplied as a factory-blended single pack, eliminating site batching errors and giving consistent results
- Can be pumped or poured, suiting both large continuous foundations and confined access situations
- Backed locally by Space Arc Engineering as an authorised Fosroc distributor and applicator with on-site method support
Limitations & considerations
- Engineered for gap thicknesses over 70mm; it should not be substituted for thin-section precision grouts such as Conbextra GP2 in shallow gaps
- Performance depends on strict adherence to the specified water content; over-watering to improve flow reduces strength and reintroduces shrinkage
- For very large or extended pours, coarse aggregate extension and the supplier’s volume guidance must be followed to manage yield and heat
- As a cementitious grout it requires proper formwork, continuous single-direction placement and curing; interrupted pours risk cold joints and voids
- Not a substitute for epoxy grouts where chemical resistance, very high dynamic fatigue resistance or thin high-precision tolerances are the governing requirement
- Ambient and substrate temperature affect flow, working time and set; hot-weather and cold-weather precautions apply
- Confirm current pack size, yield and the full numerical specification against the latest region-specific Fosroc TDS before tendering
Selection & best practice
Saturate the foundation concrete to a saturated-surface-dry condition before grouting and remove all standing water, laitance, oil and debris from the substrate and the underside of the plate. Build leak-tight formwork with a head box on the pouring side and adequate clearance on the opposite side so air can escape; for large plates keep the unrestricted flow distance reasonable. Mix only with the manufacturer-specified quantity of clean water using a forced-action or paddle mixer, never by hand, and never add extra water to chase flow. Pour or pump continuously from one side only so the advancing front pushes air ahead of it and the gap fills without trapped voids; do not pour from opposite sides simultaneously. For deep or large-volume sections, follow Fosroc’s guidance on coarse aggregate extension to control yield and further reduce heat. Cure exposed grout surfaces promptly with wet hessian or a curing membrane, and protect against rapid drying, frost and direct sun. In Indian summer conditions, use chilled mixing water and grout during cooler hours; in cold conditions protect the pour from low temperatures. Always work to the current Fosroc TDS and, for critical structural and bridge work, have Space Arc Engineering’s applicators agree a project-specific method statement.
Specifications
| Product type | Non-shrink cementitious grout (single-pack dry powder) |
| Chemical base | Cement-based, low-exothermicity binder system |
| Designed gap / section thickness | Over 70 mm (large-gap applications) |
| Consistency | Free-flowing, self-levelling |
| Heat of hydration | Low exothermicity (controlled temperature rise in thick pours) |
| Shrinkage | Non-shrink / shrinkage compensated |
| Chloride content | Chloride-free |
| Early strength | High early strength for faster commissioning |
| Placement methods | Pour or pump |
| Mixing | Add clean water at the manufacturer-specified dosage; forced-action mixer |
| Typical applications | Machine baseplates, bridge bearings, crane rails, plant foundations |
| Pack size / yield | Confirm against current region-specific Fosroc TDS |
| Compressive strength | High-strength grout grade; confirm exact values per current Fosroc TDS |
Industry use cases
Bridges & highways
Seating elastomeric and pot bearings on pier and abutment pedestals where the bearing gap exceeds 70mm, using a low-heat grout that avoids cracking under the bearing and protects embedded steel with its chloride-free formulation.
Power & process plants
Grouting turbine, generator, compressor and large pump baseplates with deep clearances in a single low-exotherm pour, achieving full contact for vibration-resistant load transfer and faster equipment commissioning.
Heavy manufacturing & steel
Bedding crane rails and gantry baseplates that carry dynamic and impact loads, where deep grout sections and reliable, void-free support are essential to long-term track alignment.
Infrastructure & precast
Filling deep column-base pockets, bolt boxes and recesses in precast and steel-frame construction where thick, self-levelling, non-shrink infill is needed around holding-down bolts.
Material handling & ports
Grouting the baseplates of large conveyors, stackers and port equipment with thick clearances, where low heat build-up and high early strength keep installation programmes on track.
Frequently asked questions
What makes Conbextra GV08 different from Conbextra GP2 or GP?
What is the minimum thickness GV08 should be used at?
Is Conbextra GV08 cementitious or epoxy?
Why is low exothermicity important for thick pours?
Can GV08 be pumped, and how should it be placed?
Does Space Arc Engineering supply GV08 across India?
How we position Fosroc Conbextra GV08
Within the Fosroc Conbextra grout range, GV08 occupies the large-gap, low-heat niche: where Conbextra GP and the popular Conbextra GP2 handle general and precision baseplate grouting in thinner sections, GV08 is the product to specify when the pour depth exceeds 70mm and thermal cracking becomes the controlling risk. It sits alongside the shrinkage-compensated Conbextra GV and high-flow Conbextra HF in the cementitious family, and is distinct from Fosroc’s epoxy grouts (such as Conbextra EP10 and EP65), which are chosen when chemical resistance or very high dynamic-fatigue resistance, rather than pour depth, governs. Against the wider Indian market, credible alternatives a consultant might evaluate include Sika’s SikaGrout high-flow non-shrink grouts, the MYK MBS (formerly MBS/MB Stanvac) cementitious grout range, Dr. Fixit’s grouting products, and STP (Shalimar Tar Products) grouts. These compete primarily in the standard precision-grout space; the specific combination of certified large-gap (>70mm) suitability with low exothermicity is GV08’s differentiator, so any substitution should be checked against equivalent low-heat, deep-section data rather than headline compressive strength alone. For procurement teams, the practical advantage of GV08 through Space Arc Engineering is authorised Fosroc supply with applicator support, which de-risks critical bridge-bearing and plant-foundation grouting where a low-cost substitute could prove far more expensive if it cracks.
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