MC-Bauchemie MC-Inject 50
A single-component, ultra-fine cement suspension grout that travels into cracks and voids ordinary cement cannot reach, rebuilding load transfer in tired concrete and old masonry.
What is it?
A single-component microfine cement suspension grout, milled below 30 microns, used for consolidation injection into fine cracks, voids and loose masonry.
Where is it used?
Structural concrete, brick and stone masonry, heritage buildings, foundations, hydraulic structures and remedial duct grouting.
Why use it?
Its fineness lets it enter cracks from roughly 0.3-0.5 mm and set as a durable, low-bleed cementitious fill without the incompatibility of resins in masonry.
How is it applied?
Mixed with clean water in a high-shear mixer, then pumped through packers or ports at low pressure until refusal, working from the lowest injection point upward.
About MC-Bauchemie MC-Inject 50
MC-Inject 50 answers a problem every repair engineer eventually meets: a structure that is cracked, delaminated or hollow inside, yet cannot be dismantled to fix. Ordinary Portland cement grout is simply too coarse to enter fine fissures, so the crack stays open and the load path stays broken. This grout is built around ultra-fine ground cement with a maximum particle size below 30 microns (d95), which is fine enough to migrate into gaps that would choke a conventional slurry. Because it is a single-component powder that needs only clean water, there is no resin-to-hardener ratio to get wrong on site, and the set material is a genuine cementitious fill that behaves compatibly with the concrete or masonry around it.
The product is aimed at consolidation rather than flexible sealing. Where an engineer wants to knit a cracked wall back together, fill honeycombing behind a facade, or restore continuity to a delaminated slab, MC-Inject 50 penetrates, sets and carries load. Its low bleed characteristic, under 5 percent by the ASTM C940 method, means the injected volume stays where it is placed instead of settling and leaving a water channel at the top of every void. For conservation work on old brick and stone, that mineral compatibility matters as much as strength: a cement-based grout ages alongside historic fabric far more gracefully than an epoxy plug ever will. Space Arc Engineering supplies and applies it across Delhi NCR and pan-India as an authorised MC-Bauchemie partner.
The technical insight
The whole performance of a consolidation grout comes down to particle size versus crack width. A grain can only travel about three to five times its own diameter into a fissure before it bridges and blocks; coarse cement, with grains often above 45 microns, jams almost immediately in a fine crack. By grinding the cement so that 95 percent of particles sit below 30 microns, MC-Inject 50 shifts that threshold down, allowing meaningful penetration into cracks from roughly 0.3 to 0.5 mm. Fineness alone is not enough, though. A microfine slurry wants to flocculate and bleed, so the formulation is stabilised to hold the particles in suspension and keep bleed water under 5 percent. That stability is what lets the grout be pumped at a low, controlled 2 to 5 bar and still fill deep interconnected voids uniformly rather than segregating into a strong bottom and a weak, watery crown. Once placed, normal cement hydration takes over, developing a compressive strength of 25 to 35 MPa at 28 days and locking the substrate back into a single monolithic mass.
Where it is used
- Consolidation injection of fine cracks in structural concrete beams, columns and slabs
- Filling internal voids and delaminations to restore monolithic behaviour
- Injection grouting of loose or de-bonded brick and stone masonry walls
- Conservation and structural stabilisation of heritage and historic buildings
- Remedial grouting of honeycombed or poorly compacted concrete pockets
- Void filling beneath foundations and in underpinning works
- Crack grouting in dams, retaining walls and other hydraulic structures
- Remediation grouting around post-tensioning ducts and cable anchorages
Key advantages
- Ultra-fine cement below 30 microns (d95) penetrates cracks coarse grout cannot enter
- Single-component system needs only water, removing on-site mixing-ratio errors
- Low bleed under 5 percent (ASTM C940) keeps the fill stable and complete
- Sets as a durable mineral fill of 25-35 MPa, compatible with concrete and masonry
- Mineral chemistry suits heritage fabric far better than rigid epoxy plugs
- Pumps with standard grout equipment at low 2-5 bar injection pressure
- Generous 60-90 minute pot life at 25 degrees C allows steady, controlled placement
- Delivered in 25 kg moisture-resistant bags for practical site handling
Limitations & considerations
- Rigid cementitious set means it consolidates and load-transfers but does not accommodate live, moving cracks the way an elastic resin does
- Penetration is practically limited to cracks around 0.3-0.5 mm and above; sub-0.3 mm hairlines usually call for a low-viscosity resin
- As a mineral grout it seals and stabilises but is not a warranted waterproofing gel for permanently wet, flexing joints
- Requires a high-shear mixer and correct 6-7 litres water per 25 kg bag; hand mixing or excess water compromises suspension stability and strength
- 60-90 minute pot life at 25 degrees C shortens in hot Indian conditions, so batch sizes must match pumping speed
- Best results depend on competent packer placement and injection sequencing; poor technique leaves unfilled voids
Selection & best practice
Start by mapping the crack pattern and voids, then drill and fix injection packers at spacings that suit the crack width, typically staggered along and across the crack. Surface-seal the crack face so grout does not simply weep out. Mix each batch in a high-shear mixer using 6 to 7 litres of clean water per 25 kg bag, adding powder to water and mixing to a smooth, lump-free suspension; do not exceed the water dose to chase flow. Inject at a low, steady 2 to 5 bar, always working from the lowest packer upward and moving on only when grout appears at the next port, which confirms the void between them is full. Respect the 60 to 90 minute pot life and size batches to what you can pump before it stiffens, mixing fresh rather than retempering. In hot weather use cooler water and smaller batches. After curing, remove packers and make good the surface. On heritage or specifier-led work, always confirm crack widths, target strength and injection sequence against the project spec and MC-Bauchemie’s current technical data sheet.
Specifications
| Product type | Single-component microfine cement suspension grout |
| Maximum particle size | <30 microns (d95) |
| Bleed water | <5% (ASTM C940) |
| Compressive strength (28 days) | 25-35 MPa |
| Mixing ratio | 6-7 litres clean water per 25 kg bag |
| Typical injection pressure | 2-5 bar |
| Minimum crack width for penetration | 0.3-0.5 mm |
| Pot life | 60-90 minutes at 25 degrees C |
| Packaging | 25 kg moisture-resistant paper bags |
Industry use cases
Heritage & Conservation
Consolidating loose stone and brick masonry in old monuments and buildings, where a mineral grout is compatible with historic fabric and reversible techniques are valued.
Structural Repair & Rehabilitation
Re-knitting cracked and delaminated concrete beams, columns and slabs in ageing commercial and residential structures to restore monolithic load transfer.
Dams & Hydraulic Structures
Grouting fine cracks and interconnected voids in dam bodies, spillways and retaining walls to reduce seepage paths and consolidate the mass.
Foundations & Underpinning
Filling voids beneath footings and rafts during underpinning and settlement remediation, re-establishing continuous bearing contact with the ground.
Infrastructure & Bridges
Remedial grouting of honeycombed pours and post-tensioning duct zones where fine penetration and durable cementitious fill are required.
Frequently asked questions
How fine a crack can MC-Inject 50 actually penetrate?
Is this a waterproofing grout or a structural one?
Why choose a microfine cement grout over an epoxy injection?
How much water do I add per bag?
What strength does the set grout reach?
Can Space Arc apply it, or only supply it?
How we position MC-Bauchemie MC-Inject 50
MC-Inject 50 is the microfine, single-component consolidation grout in the MC-Bauchemie injection range. Where crack widths are larger or you want a two-component fine mineral suspension, the same MC-Bauchemie family offers the Centricrete cement-suspension grouts (Centricrete HCS single-component from about 0.8 mm, and Centricrete UF two-component from about 0.4 mm). When a crack is moving or permanently wet, step across to MC-Bauchemie’s resin systems instead: the MC-Injekt 1264 epoxies for rigid structural bonding from 0.1 mm, or the MC-Injekt 2300 and 2700 polyurethanes and GL-95 acrylate gels for flexible, waterproof sealing. For non-shrink structural grouting of larger gaps under baseplates and machine feet, that is a different job served by flowable precision grouts such as Fosroc Conbextra GP2 in our wider portfolio rather than by a fine crack-injection grout like this one.
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Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.