MC-Bauchemie MC-Injekt 640
A low-viscosity, two-component epoxy resin that penetrates and structurally re-bonds dormant cracks in reinforced concrete, restoring monolithic load transfer.
What is it?
A solvent-free, two-component (resin plus amine hardener) low-viscosity epoxy injection resin from MC-Bauchemie, formulated to fill and structurally glue static cracks in concrete.
Where is it used?
Cracked RCC beams, columns, slabs, raft foundations, bridge and flyover girders, dam and retaining walls, and industrial frames where the crack has stopped moving.
Why use it?
Its very low mixed viscosity lets it travel into hairline cracks down to about 0.1 mm and cure to a rigid bond stronger than the parent concrete, so the member behaves as one piece again.
How is it applied?
Cracks are cleaned and V-sealed, surface ports (packers) are fixed, the two parts are mixed to the TDS ratio, and the resin is pumped under low pressure until it refuses at the next port.
About MC-Bauchemie MC-Injekt 640
MC-Injekt 640 belongs to MC-Bauchemie’s structural injection family, the solutions engineers reach for when a concrete member has cracked but is no longer moving. It is a two-part epoxy: a low-viscosity bisphenol-A resin (Component A) mixed on site with an amine hardener (Component B). Once combined and injected, it stops being a liquid and becomes a rigid adhesive that welds the two crack faces back together. The point is not to hide the crack cosmetically but to restore the structural continuity of the section, so loads once again pass across the crack instead of concentrating at its tips.
For Indian projects, the practical appeal is penetration and strength. The mixed resin sits at roughly 200 to 400 mPas, thin enough to wick into hairline separations that thicker mortars and grouts cannot reach, yet it cures to an epoxy with tensile strength in the region of 35 to 40 MPa. Because the cured bond typically fails in the concrete rather than at the glue line, a correctly injected crack is effectively as strong as the surrounding member. That combination is why consultants specify it for high-value assets such as bridge beams, RCC columns, dam walls and industrial structures, where the alternative to repair is expensive demolition and recasting.
The technical insight
A crack in reinforced concrete is a discontinuity: the section can no longer transfer tension or shear cleanly across the gap, and every load cycle works the crack tip a little harder. MC-Injekt 640 solves this by capillary action followed by chemistry. The very low viscosity of the freshly mixed resin means that, under modest injection pressure, it is drawn deep along the crack plane, coating both faces right into the fine tributaries a thicker material would bridge over and seal shut at the mouth. The amine hardener then cross-links the epoxy into a rigid, three-dimensional network keyed to the concrete on both sides. Because that cured network develops a tensile bond to the substrate greater than around 3.0 MPa (tested to EN 1542, with failure occurring in the concrete rather than the resin), the repaired plane is no longer the weak line in the member. The design intent is monolithic behaviour, which is exactly why the product is meant for dormant cracks only: a rigid epoxy has no capacity to accommodate ongoing movement, so if the crack is still live it will simply re-crack alongside the cured resin.
Where it is used
- Structural crack injection in bridge and flyover girders and deck beams
- Repair of load-bearing cracks in RCC columns, beams and slabs
- Crack consolidation in concrete dams, spillways and retaining walls
- Rehabilitation of industrial structures such as crane gantry beams, machine foundations and portal frames
- Injection of foundation, raft and pile-cap cracks to restore section continuity
- Elevated water-tank staging, ring-beam and column crack repair
- Monolithic re-bonding of cracked precast and cast-in-situ elements
- Strengthening works where cracks must be sealed before external plate or laminate bonding
Key advantages
- Low mixed viscosity (approx. 200 to 400 mPas) penetrates hairline cracks down to about 0.1 mm
- Cured epoxy develops high tensile strength (approx. 35 to 40 MPa), restoring monolithic load transfer
- Bond to concrete exceeds roughly 3.0 MPa with substrate-mode failure, so the joint is not the weak point
- Solvent-free formulation, avoiding shrinkage and solvent-entrapment problems during cure
- Two-part system with a defined mix ratio gives predictable, repeatable curing on site
- Suited to high-value structural assets where demolition and recasting is not an economic option
- Compatible with standard low-pressure packer-and-pump injection practice used across Indian repair contractors
- Backed by Space Arc supply and trained applicator support across Delhi NCR and Pan-India
Limitations & considerations
- Rigid on cure, so it is only for dormant (non-moving) cracks; live or expanding cracks will re-open beside the resin
- Not intended for actively leaking or water-running cracks, where an elastic or hydro-active resin is the correct choice
- Needs cracks that are dry or only slightly damp; standing water and grease interfere with bonding and cure
- Pot life of roughly 30 to 45 minutes at 20 C shortens sharply in Indian summer heat, so batch sizes and pumping pace must be planned
- Requires disciplined surface preparation, port spacing and injection technique; poor workmanship leaves voids and cold joints
- Crack should be monitored beforehand to confirm it has genuinely stopped moving
Selection & best practice
Success is decided before a drop of resin is pumped. First confirm the crack is dormant, using tell-tales or monitoring over a period rather than assuming. Rout or wire-brush the crack line, remove dust, laitance, oil and any loose material, and make sure the crack is dry or at most slightly damp. Fix injection packers along the crack at a spacing roughly equal to the member thickness, and surface-seal the crack line between ports with a fast-setting epoxy paste so the resin travels along the crack instead of bleeding out. Mix Components A and B strictly to the current TDS ratio and only in quantities you can inject inside the pot life, remembering that Delhi NCR summer temperatures cut that window. Inject at low pressure from the lowest port on vertical work, moving up only when resin appears at the next port, then plug and advance. After cure, grind off the surface seal and packers flush. On hot days, work early or shaded, keep material cool before use, and mix smaller batches more often.
Specifications
| Product type | Two-component, solvent-free low-viscosity epoxy injection resin |
| Components | A: bisphenol-A epoxy resin; B: amine hardener |
| Mixed viscosity (approx., 20 C) | 200 to 400 mPas |
| Pot life (approx., 20 C) | 30 to 45 minutes (shorter in heat) |
| Crack width injectable | From about 0.1 mm (hairline) upward |
| Tensile bond to concrete (EN 1542) | > 3.0 MPa, concrete substrate failure |
| Cured tensile strength (approx.) | 35 to 40 MPa |
| Reference standards | EN 1504-5 (injection products), EN 1542 (bond) |
| Crack condition suited | Dormant, dry to slightly damp |
Industry use cases
Bridges & Highways
Re-bonding flexural and shear cracks in prestressed and RCC girders, deck beams and piers so the span recovers full load capacity without replacement.
Water & Wastewater
Restoring cracked columns, ring beams and staging of elevated tanks and STP structures, provided the crack is dormant and the surface can be dried for injection.
Industrial & Power
Repairing cracked crane gantry beams, machine foundations, chimneys and portal frames where downtime for recasting would be prohibitively expensive.
Dams & Hydraulic Works
Consolidating cracks in mass-concrete dam bodies, spillways and retaining walls to re-establish monolithic behaviour in the section.
Buildings & High-Rise
Structural stitching of dormant cracks in columns, beams, rafts and cores, often as preparation before external strengthening with plates or fabrics.
Frequently asked questions
Is MC-Injekt 640 suitable for cracks that are still moving?
Can it be used on a crack that is actively leaking water?
How fine a crack will it actually enter?
Will the repaired crack be as strong as the original concrete?
How does the pot life behave in Delhi NCR summers?
Does Space Arc only supply the material, or can you apply it too?
How we position MC-Bauchemie MC-Injekt 640
Choose MC-Injekt 640 when the crack in a concrete member is structural but dormant and you want to restore monolithic, load-bearing continuity with a rigid low-viscosity epoxy. If the same crack is wet, leaking or still moving, it is the wrong tool: within the MC-Bauchemie injection range, move to an elastic or hydro-active resin such as the MC-Injekt 2300 family for water-bearing and slightly moving cracks, while MC-Injekt 1264 compact is the companion rigid epoxy option for binding and sealing structural cracks. Where the wider repair calls for patch mortars, bonding agents or protective coatings around the injected zone, we can specify the matching MC-Bauchemie repair and Nafufill/Emcephob systems. Because Space Arc also carries Fosroc, Sika and Dr. Fixit lines, we can cross-supply an equivalent from another brand family when a project’s approved-vendor list or budget requires it, rather than forcing a single label.
Fosroc Nitofill LV — A specifier already standardised on Fosroc, or working to a Fosroc-approved vendor list, may prefer Nitofill LV, which is the directly equivalent two-part low-viscosity epoxy for injecting dormant structural cracks.
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