About MC-Bauchemie Centricrete HCS

Centricrete HCS is MC-Bauchemie’s single-component, cement-based injection suspension built for one specific job: filling cracks, construction joints and cavities in concrete and masonry so completely that the defect is structurally closed, not just sealed on the surface. Unlike a waterproofing coating or membrane that sits on top of concrete, Centricrete HCS is pumped into the structure itself, through drilled packers, so the grout occupies the actual crack width and cavity volume. It ships as a grey powder in 20 kg bags and is gauged on site with water at a 20:7 (or 20:8) ratio by mass in a high-shear colloidal mixer, which keeps the ultra-fine cement particles suspended and pumpable long enough to reach tight cracks before the mix begins to set. For project sites across Delhi NCR and pan-India, that translates into a product crews reach for on basement rafts, retaining walls, water-retaining structures and tunnel segments where a crack is confirmed to be dormant (non-moving) but is letting water through, and needs a genuinely rigid, load-transferring repair rather than a flexible sealant.

What sets Centricrete HCS apart from a generic OPC grout mixed on site is that MC-Bauchemie has engineered it to stay workable long enough for multi-point packer injection, then develop strength fast — its own EN 196-1 testing shows flexural strength already in the 4.7–5 N/mm² range at 24 hours — while curing with almost no shrinkage or expansion (around 0.1% volumetric change), so it doesn’t open a fresh hairline crack around the very defect it just filled. It’s also chloride-free and carries a re-alkalising action, which matters on carbonation-damaged RCC where the real goal of injection is as much about protecting embedded reinforcement as it is about stopping water. In practice, it’s best understood as the cementitious half of MC-Bauchemie’s injection portfolio: for dormant, water-bearing structural cracks it’s usually the right call, while actively leaking joints with some ongoing movement, or genuinely dynamic and thermal cracks, are better served by PU or epoxy resin injection grades that can flex rather than hold rigid.

The technical insight

The mixing method is not a formality with this product — it’s the whole point. Centricrete HCS is a micro-fine cement suspension, and the manufacturer’s own datasheet is explicit that a colloidal (high-shear) mixer gives the best injectability because it keeps the cement particles deflocculated in suspension rather than letting them clump and settle, which is exactly what would clog a packer mid-injection. MC-Bauchemie even quantifies the trade-off: mixing with a standard four-arm drill paddle at a minimum of 800 rpm still works for cavity injection, but the resulting suspension is measurably less flowable — its own literature attributes this directly to lower mixing energy — than what a colloidal mixer produces, so for genuine crack injection through packers the colloidal mixer isn’t optional. The flow/efflux time of roughly 80–100 seconds (EN 14117, 4.76 mm cone) is the practical number crews should check on site before pumping: if a batch runs thicker than that, it hasn’t been mixed correctly and won’t penetrate a fine crack. On the strength side, a dynamic E-modulus of around 24,000 N/mm² at 28 days confirms this cures into an actual rigid, load-sharing fill approaching the stiffness of the surrounding concrete — which is exactly why it’s specified for structural crack injection and never marketed as a flexible or elastomeric system.

Where it is used

• Rigid-fill injection of dormant, water-bearing cracks in RCC basements, retaining walls and foundations
• Filling and reinforcing construction/cold joints where water is tracking through the joint line
• Grouting voids, cavities and honeycombing in concrete and masonry under dry, damp or water-flow conditions
• Pre-injection of larger cavities ahead of a full-surface waterproofing injection or tanking programme
• Crack injection in water-retaining structures — sumps, tanks, STPs and canal linings
• Structural crack repair in tunnel segments, shafts and underground metro or utility structures
• Re-alkalising injection around reinforcement in carbonation-affected columns, beams and foundations

Key advantages

• Single-component — only potable water is added on site, cutting the batching error that comes with multi-part systems
• Long open/working time gives crews the margin to complete a full main-injection-plus-re-injection cycle through multiple packers without racing the clock
• Fast early strength (flexural strength already ≈4.7–5 N/mm² at 24 hours per EN 196-1) lets structures return to service sooner
• Cures with only ≈0.1% volumetric change — effectively shrinkage- and expansion-free, so it doesn’t reopen the crack it just filled
• Chloride-free and re-alkalising, which helps passivate reinforcement in carbonated concrete rather than just plugging the crack
• One product handles dry, damp and actively water-bearing cracks, so specifiers don’t need to switch systems for wet sites
• Backed by an Environmental Product Declaration (EPD), useful where projects are tracking green-building documentation

Limitations & considerations

• Cures rigid, not elastic — not the right choice for cracks with ongoing structural movement, vibration or thermal cycling; a PU or flexible resin injection belongs there instead
• Needs a colloidal (high-shear) mixer for full injectability; mixing with a basic drill paddle is usable only for cavity work and gives a visibly less flowable, less penetrating suspension
• Application depends on a proper injection pump and packers (the manufacturer specifies its own low-pressure single-component pump with Hammer/Surfacepackers) — this is a specialist-crew product, not a pour-and-patch mortar
• Work must stop once component or substrate temperature drops below 5°C
• Published only in a 20 kg bag — there’s no small pack for one-off patch jobs, so minimum order quantities matter for small repairs

Selection & best practice

Specifications

Industry use cases

How we position MC-Bauchemie Centricrete HCS

Within MC-Bauchemie’s own range, Centricrete HCS sits alongside the company’s PU and epoxy resin injection grades — the cementitious choice for dormant, water-bearing structural cracks, while the resin systems take over where a crack is still moving or where a fast-setting, hydrophobic chemistry is needed to chase and stop actively flowing water first. It’s also positioned as the pre-injection step ahead of MC-Bauchemie’s broader waterproofing and tanking systems, closing cavities before a membrane or coating goes on. On site it’s typically specified together with dedicated injection hardware — a low-pressure single-component pump and Hammer or Surfacepacker fittings — rather than treated as a standalone bag-and-trowel material, since the injection method is as much a part of the specification as the grout itself. Where a project genuinely needs the flowing-water performance of a PU chemistry rather than a rigid cementitious fill, Fosroc’s Nitofill PU23 is a credible alternative from a brand Space Arc also carries — it’s built specifically to chase and seal active water leaks in basements and tunnels, though it cures to a rigid foam rather than Centricrete HCS’s re-alkalising cement matrix, so the choice usually comes down to whether reinforcement passivation or fast leak-chasing is the priority on that particular crack.

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