About Sika Sikadur-43 HE (h)

Sikadur-43 HE (h) is Sika’s heavy-duty answer to concrete that has lost section: spalled cover, honeycombed pours, corrosion-damaged edges and voids that a cementitious mortar simply cannot rebuild to the strength the structure needs. It is supplied as a three-part system — a liquid epoxy resin (Part A), a hardener (Part B) and a graded aggregate filler (Part C) — pre-batched into a single 25.2 kg unit so there is no site guesswork over ratios. Once the three parts are combined they cure to a dense, dimensionally stable grey mortar that carries load far in excess of the parent concrete around it.

What sets it apart on an Indian site is the combination of speed and buildability. The thixotropic consistency lets a mason place it on beam soffits and column faces up to 50 mm deep in one pass without slumping, while the high-early-strength chemistry means a repair placed in the morning is already carrying meaningful load by the next day. That makes it a natural fit for repairs on live plants, bridge maintenance under traffic windows, and any rehabilitation job where downtime is the real cost. Space Arc Engineering supplies Sikadur-43 HE (h) as an authorised Sika channel partner across Delhi NCR and Pan-India, with technical guidance on substrate prep and system selection.

The technical insight

The performance comes from the epoxy binder itself. Unlike a cement mortar, which gains strength by slow hydration and always carries some porosity, Sikadur-43 HE (h) cures through an exothermic cross-linking reaction between the resin and hardener that forms a continuous, effectively void-free polymer matrix locking the graded aggregate in place. That matrix is what delivers ~108 N/mm2 compressive strength — roughly three times a typical structural grade concrete — along with high flexural and tensile capacity and near-zero water absorption. The (A+B):C ratio of 1:4.8 by volume is deliberately aggregate-rich: enough resin to fully wet and bind every particle, but a high filler load to keep shrinkage and creep low and to give the mortar its non-sag, trowel-holding body. Because the epoxy chemically bites into the substrate, the repair bonds without a separate bonding coat and tolerates a damp (though not visibly wet) surface, which is a practical advantage on real repair sites where concrete is rarely bone dry.

Where it is used

• Structural patch repair of spalled, honeycombed or corrosion-damaged concrete
• Reprofiling and rebuilding lost concrete cover on beams, columns and slabs
• Overhead and vertical repairs on soffits, bridge undersides and cantilevers up to 50 mm thick
• Filling voids, blowholes and form-tie pockets in structural elements
• High-load repairs to industrial and warehouse floors subject to traffic and impact
• Rebuilding edges of construction joints, kerbs and machine bases
• Repairs to water-retaining and marine structures needing a low-permeability mortar
• Bonding and fixing of steel and masonry elements into concrete

Key advantages

• Very high compressive strength, up to ~108 N/mm2 at 14 days
• High early strength — around 85 N/mm2 within 24 hours for fast return to service
• Thixotropic, non-sag body allows 50 mm builds on vertical and overhead faces in one pass
• Bonds tenaciously to concrete, steel and masonry without a separate primer
• Tolerates damp (not wet) substrates common on repair sites
• Pre-batched three-part unit removes on-site mixing-ratio errors
• Low permeability and negligible water absorption for durable, protective repairs
• Solvent-free formulation suited to enclosed and confined-space working

Limitations & considerations

• Short working window — pot life is only around 35 minutes at +30°C, so mix only what can be placed in time
• Must be applied within +5°C to +40°C; hot Indian afternoons shorten pot life sharply
• Not suitable for large-area or economy repairs where a cementitious mortar is more cost-effective
• Substrate must be damp but not standing wet, and free of loose material, laitance and contamination
• Rigid epoxy — its stiffness must be matched to the structure; not intended for movement or expansion joints
• Higher unit cost than polymer-modified cementitious repair mortars

Selection & best practice

Specifications

Industry use cases

How we position Sika Sikadur-43 HE (h)

Sikadur-43 HE (h) sits at the high-strength, structural end of Sika’s repair range. Where the damage is shallow and cosmetic or the area is large, a polymer-modified cementitious mortar such as the Sika MonoTop family is the more economical route; where you need to bond new-to-old concrete or fix steel plates and dowels, Sika’s Sikadur structural adhesives (for example the Sikadur-31 range) are the natural companions. For crack injection alongside a patch repair, pair it with Sika’s low-viscosity Sikadur injection resins. Buyers cross-shopping brands in our catalogue will find comparable epoxy-based structural repair systems from Fosroc, and MC-Bauchemie’s repair mortars where a specification calls for those houses.

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