About STP ShaliBond LAM

STP ShaliBond LAM sits at the heart of STP’s Restofix external plate-bonding system, the adhesive that turns a pre-cured ShaliLam C carbon-fibre laminate into a working part of the structure. Retrofit strengthening only succeeds if the load can actually cross from the concrete into the laminate, and that crossing happens entirely through the glue line. ShaliBond LAM is formulated for exactly that duty: a rigid, high-modulus, two-component epoxy that cures to a bond stronger than the parent concrete, so failure, when pushed to the limit, occurs in the substrate rather than at the interface. For engineers and consultants specifying a strengthening scheme in Delhi NCR or anywhere across India, it is the component that makes the design numbers real on site.

What makes the product practical for Indian site conditions is its thixotropy. Most CFRP plate bonding happens on the underside of beams and slabs or on vertical column and shear-wall faces, where a runny adhesive would sag, starve the joint and drip. ShaliBond LAM is deliberately buttery and non-slump, so an applicator can trowel a controlled ridge onto both faces, offer up the laminate overhead, and trust the paste to stay put through the working time and cure. Being solvent-free, it carries no shrinkage from evaporating carriers and no flash-off in enclosed soffits or basements, which matters for both bond integrity and applicator safety. Space Arc Engineering supplies and applies it as an authorised STP channel partner, so the laminate, the adhesive and the site method arrive as one coordinated package rather than three loosely matched buys.

The technical insight

Plate bonding is a shear-transfer problem, not a gluing problem. When a strengthened beam deflects, the concrete and the CFRP laminate try to strain by different amounts, and that difference is resolved as interfacial shear stress carried entirely by the adhesive layer between them. ShaliBond LAM works because a rigid, high-modulus epoxy keeps that thin bond line stiff enough to transfer the shear without excessive slip, so the laminate genuinely picks up tension instead of merely riding along. The thixotropic rheology serves the same structural goal from the other direction: a consistent, void-free, correctly-thick glue line is what the design assumes, and a non-sag paste is how you actually achieve it on a soffit. Because the epoxy is solvent-free reactive chemistry, it cures by cross-linking rather than by drying, so there is no solvent shrinkage pulling the interface apart and the cured line reaches a cohesive strength that exceeds concrete’s tensile capacity, which is why properly executed joints fail in the concrete cover, not the bond.

Where it is used

• Flexural strengthening of RC beams and slabs by bonding ShaliLam C laminates to the tension soffit
• Shear strengthening of beams using laminate strips bonded to the web faces
• Increasing load capacity of bridge girders and decks during rehabilitation or load upgrades
• Strengthening slabs and beams to accommodate change-of-use or increased imposed loads
• Retrofitting members weakened by corrosion, overloading or design deficiency
• Overhead and vertical laminate bonding where a non-sag adhesive is essential
• Seismic upgrade schemes where added flexural capacity is specified
• Repairing and reinstating strength in industrial and commercial framed structures

Key advantages

• Two-component, solvent-free epoxy with no shrinkage from evaporating carriers
• Thixotropic, non-slump paste that holds on soffits and vertical faces during cure
• Develops a bond stronger than the parent concrete, so failure stays in the substrate
• High-modulus, rigid bond line that transfers shear efficiently into the laminate
• Purpose-matched to STP’s pultruded ShaliLam C carbon-fibre laminates
• Clean, low-odour handling in enclosed soffits and basements without solvent flash-off
• Adds significant structural capacity with negligible added dead load or member size
• Supplied and applied by Space Arc as a coordinated STP system, not a mixed-brand assembly

Limitations & considerations

• A rigid structural adhesive, not a gap-filler or crack-injection resin; large voids need epoxy mortar first
• Bond depends completely on substrate prep; laitance, dust, oil or damp concrete will compromise the joint
• Two-part epoxy with a limited working life once mixed, so batches must be sized to what can be placed
• Cure rate and pot life are temperature-sensitive, requiring care in Indian summer or cold-morning placement
• Requires trained applicators and correct mix ratio; site-guessed proportions undermine the design assumptions
• Not a substitute for addressing the root cause where deterioration is ongoing, such as active corrosion or leakage

Selection & best practice

Specifications

Industry use cases

How we position STP ShaliBond LAM

ShaliBond LAM is only half of a system, and it should be specified alongside its natural companions from the STP Restofix range: the ShaliLam C pultruded carbon-fibre laminate it bonds, and ShaliFix EM / EM 51 epoxy mortars for making good honeycombing and levelling the substrate before bonding. Where a project calls for wet-layup carbon or glass fabric wrapping of columns and beams instead of plate bonding, STP’s ShaliWrap CF and ShaliWrap GF fabrics are the sister solution. Because Space Arc also distributes Fosroc, consultants who prefer to keep an entire strengthening scheme within the Fosroc ecosystem can look at the Nitoplate CPS plate-bonding system or the Nitowrap CW carbon-fabric system as equivalents. We stock both families and will match the specification to the design rather than to the brand.

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