STP ShaliLam C
Factory-pultruded carbon fibre laminate from STP Limited that raises the flexural capacity of beams, slabs and girders — cold-bonded with ShaliBond Lam epoxy, just 1.4 mm thick, with no added dead load and no corrosion to manage later.
What is it?
A ready-to-use pultruded carbon fibre reinforced polymer (CFRP) strip with 68% fibre content, tensile strength above 2,800 MPa and a modulus above 165 GPa, supplied in 100 m rolls in 50 mm and 100 mm widths.
Where is it used?
On the tension face of RC beams, slab soffits, bridge girders, and on masonry, brickwork and timber members that need more bending or load-carrying capacity.
Why use it?
It delivers steel-plate-level tensile capacity at a fraction of the weight, adds only 1.4 mm to the member, never rusts, and can be installed while the structure stays in service.
How is it applied?
Bonded to sound, prepared concrete using ShaliBond Lam two-part epoxy at a minimum 2 mm bondline, pressed until adhesive squeezes out along both edges, then overcoated where exposed to sunlight.
About STP ShaliLam C
ShaliLam C is STP Limited’s externally bonded strengthening laminate — a unidirectional carbon fibre strip pulled through an epoxy matrix under factory-controlled pultrusion, so every metre arrives with the same 68 ± 2% fibre content and guaranteed minimum properties. Two grades cover most designs: ShaliLam C 1450 at 50 mm width (70 mm² cross-section) and C 1410 at 100 mm (140 mm²), both 1.4 mm thick. With tensile strength exceeding 2,800 MPa and elastic modulus above 165 GPa, a single strip replaces reinforcement capacity that would otherwise demand bulky bonded steel plates or section enlargement.
For Indian retrofit work — bridge girders under revised IRC loading, buildings changing use, structures repaired after reinforcement corrosion — the laminate approach means no welding, no propping of heavy plates and no lost headroom. ShaliLam C works as a system with ShaliBond Lam structural epoxy adhesive and STP’s RestoFix repair range. Space Arc Engineering supplies the complete system and provides trained application crews across Delhi NCR and pan-India, so material, design coordination and installation come from one accountable source.
The technical insight
An externally bonded laminate works as an additional tension chord glued to the member. Because pultrusion aligns every fibre along the strip’s axis, the composite reaches its full stiffness immediately — at more than 165 GPa, ShaliLam C begins carrying meaningful stress at the small strains a loaded beam actually experiences, which is exactly why modulus, not just ultimate strength, is the property that matters in flexural strengthening. The epoxy bondline transfers force from concrete into the strip by shear, so the weakest link is almost always the substrate, not the carbon: design is governed by concrete pull-off strength and by debonding strain limits well below the laminate’s 1.7% elongation at break. The strip’s 55 MPa interlaminar shear strength ensures the composite itself will not delaminate before those substrate limits are reached — a direct benefit of factory curing over site wet layup.
Where it is used
- Flexural strengthening of RC beam and slab soffits where imposed loads have increased
- Bridge girder and deck strengthening for revised axle loads or carriageway widening
- Restoring capacity lost to reinforcement corrosion, after concrete repair is completed
- Seismic retrofit of buildings and structural upgrading to current code requirements
- Change-of-use projects — new floor openings, mezzanines, heavier plant and equipment
- Correcting design or construction defects such as under-provided reinforcement
- Strengthening timber and masonry members in rehabilitation and heritage structures
- Shear and confinement strengthening as part of a designed composite system
Key advantages
- Tensile strength above 2,800 MPa — several times that of structural steel plate, at roughly a fifth of the weight
- Only 1.4 mm thick, so headroom and clearances in buildings and parking decks are preserved
- Carbon does not corrode — unlike bonded steel plates, there is no repainting or rust maintenance ever
- Supplied in 100 m rolls and cut to length on site, keeping wastage and handling effort low
- Installed by hand with no welding, drilling of tendons or heavy lifting; structures can remain in service
- Fast-curing ShaliBond Lam adhesive shortens possession windows on bridges and busy facilities
- Two widths (50/100 mm) let the designer match cross-sectional area to demand economically
- Factory pultrusion gives consistent, certificate-backed properties versus the variability of site wet layup
Limitations & considerations
- A design-led product: strip sizing and spacing must come from a qualified structural engineer, and usable design strain is capped well below the laminate’s ultimate capacity by debonding limits
- The substrate governs performance — deteriorated concrete must first be repaired (ShaliFix FRM range) and allowed at least three weeks before bonding
- Flat, straight surfaces only; the laminate must never be bent or folded, so curved profiles and column wrapping call for carbon fabric systems instead
- The epoxy bondline softens at elevated temperature and provides no fire rating — separate fire protection is needed where a rating is specified
- Permanent sunlight exposure requires a protective PU overcoat (ShaliProtek 2AC PU TC or ShaliUrethane PU TC 2K)
- Results depend on workmanship: bondline thickness, void-free pressing and surface preparation need a trained applicator, not a general contractor
Selection & best practice
Start with the substrate: concrete must be sound, dry and open-textured, with all paint, curing compound and laitance removed. Repair spalled areas with the ShaliFix FRM mortar range — treating corroded bars with ShaliRust Off and ShaliPrime Zn zinc-rich primer first — and wait a minimum of three weeks before bonding. Fill blowholes and depressions with ShaliFix 3EP epoxy putty so the strip seats on a continuous plane. Cut ShaliLam C to length, then mix ShaliBond Lam components A and B with a slow-speed drill and spiral paddle until homogeneous, letting entrapped air escape before use. Apply the adhesive to the laminate at a minimum 2 mm thickness and press the strip onto the substrate until excess squeezes out along both edges; strike off the surplus. If plastering over, apply a bond coat and broadcast oven-dried quartz sand; in sunlight, finish with the recommended PU topcoat. Clean tools with solvent before the epoxy sets.
Specifications
| Form / grades | Pultruded CFRP laminate — ShaliLam C 1450 and C 1410 |
| Width x thickness | 50 mm x 1.4 mm (C 1450); 100 mm x 1.4 mm (C 1410) |
| Cross-sectional area | 70 mm² (C 1450); 140 mm² (C 1410) |
| Tensile strength | > 2,800 MPa |
| Modulus of elasticity | > 165 GPa |
| Elongation at break | > 1.7% |
| Fibre content / density | 68 ± 2% / 1.6 g/cm³ |
| Interlaminar shear strength | 55 MPa |
| Supply / shelf life | 100 m rolls; 12 months in original sealed packing, stored cool and dry |
Industry use cases
Bridges & Flyovers
Strengthening girder soffits and deck slabs for higher axle loads or IRC loading revisions, with short possession windows thanks to the fast-curing adhesive.
Commercial Buildings
Upgrading slabs and beams around new openings, mezzanine additions or heavier occupancy without losing floor-to-ceiling height.
Industrial Plants
Reinforcing floor beams and supporting members for new machinery loads while production continues — no hot work, no heavy plate handling.
Parking Structures
Headroom-critical flexural strengthening where every millimetre of clearance matters and bonded steel plates are impractical.
Heritage & Institutional
Discreet strengthening of timber and masonry members in older buildings, adding capacity with minimal visual and dimensional impact.
Frequently asked questions
What is the difference between ShaliLam C 1450 and C 1410?
Which adhesive should be used, and can I substitute another epoxy?
Can the laminate be plastered or painted over after installation?
Should I use a laminate or a carbon fibre wrap fabric?
How soon after concrete repair can ShaliLam C be bonded?
Do I need a structural design before ordering material?
How we position STP ShaliLam C
ShaliLam C is the flexural workhorse of STP’s RestoFix strengthening family, and it rarely travels alone: pair it with ShaliBond Lam adhesive, the ShaliFix FRM repair mortars, ShaliPrime Zn for bar protection and ShaliFix 3EP putty for surface fairing, with ShaliProtek 2AC PU TC as the UV topcoat outdoors. For column confinement or curved geometry where a rigid strip cannot go, a wrap system such as Fosroc Nitowrap EP is the better tool. Specifiers standardising on Fosroc across a project can achieve the same plate-bonding approach with Nitoplate CPS — Space Arc stocks and applies both systems, so the choice can follow the design, not the other way around.
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