About MC-Bauchemie MC-Admix C8000

Most waterproofing strategies protect concrete from the outside in — a membrane, a coating, a barrier applied after the pour. MC-Admix C8000 works the other way round: it’s dosed into the concrete mix itself, so the finished structure is waterproof by composition rather than by an applied layer that can be punctured, torn or missed during backfilling. As a dry-powder crystalline admixture, its active agents react with the water and unhydrated cement already present in the mix, growing insoluble crystals inside the capillary pore structure that physically block the paths water would otherwise use to migrate through the concrete.

That integral approach is why MC-Bauchemie positions it for structures where a punctured or poorly-lapped membrane would be a serious, hard-to-fix failure — basement raft slabs, underground car parks, water-retaining structures, tunnel and metro linings, and swimming-pool shells. It resists hydrostatic pressure from both the positive (water-facing) and negative (dry) side, which membrane systems generally can’t do without a specific negative-side product, and because the crystalline reaction keeps working as long as moisture is present, it goes on self-sealing hairline cracks up to 0.4mm long after the pour is finished.

The technical insight

The mechanism is what separates a crystalline admixture from a bulk waterproofing additive: it isn’t just densifying the mix, it’s growing insoluble crystalline structures inside the capillary network as a chemical reaction with water and unhydrated cement. That reaction has two practical consequences worth understanding before specifying it. First, because the reaction needs moisture to proceed, it is dormant in dry concrete and reactivates whenever water reaches it — which is exactly why it keeps self-sealing hairline cracks up to 0.4mm that open up months or years after casting, not just at the point of pour. Second, because the waterproofing lives inside the pore structure rather than on a surface, it resists water pressure from both faces of the concrete equally — a genuine advantage over membrane systems, which are typically engineered for one-directional (usually positive-side) pressure and need a different, more specialised product for negative-side conditions like a basement wall being de-watered from inside.

Where it is used

• Basement raft slabs and retaining walls, integral waterproofing against groundwater hydrostatic pressure
• Underground car park slabs and walls, positive- and negative-side hydrostatic water resistance
• Water tanks, reservoirs and sumps, potable-water-compatible integral waterproofing
• Tunnel and metro structure concrete, integral crystalline waterproofing from the cast stage
• Swimming-pool shell concrete, integral waterproofing alternative to a tanking membrane under tiles
• Pile caps and foundation concrete, protection against aggressive groundwater

Key advantages

• Integral waterproofing, permanently part of the concrete rather than a damageable surface membrane
• Self-seals hairline cracks up to 0.4mm as they form over time
• Works against water pressure from both the positive (water) and negative (dry) side
• Potable-water safe and non-toxic, suitable for drinking-water and food-processing structures
• No additional membrane needed, shortening the construction programme and removing membrane cost
• Permanent — the crystalline reaction continues for the life of the structure while moisture is present

Limitations & considerations

• Not a repair or retrofit product — it has to be dosed into fresh concrete at batching, so it can’t waterproof an existing structure after the fact
• Self-sealing is rated up to 0.4mm crack width; wider structural cracks still need a dedicated repair or injection system
• Dose rate is project- and mix-specific rather than a single fixed figure, so it needs to be confirmed against the current TDS and the actual concrete mix design before batching
• Being a batching-plant admixture, it depends on correct dosing and mixing discipline at the plant — it isn’t a site-applied product a contractor can adjust after the pour
• As with any integral system, it protects the concrete itself but doesn’t address construction joints or penetrations, which still need dedicated waterstops or joint treatment

Selection & best practice

Specifications

Industry use cases

How we position MC-Bauchemie MC-Admix C8000

MC-Admix C8000 solves integral waterproofing at the batching stage; it doesn’t replace joint treatment or surface protection elsewhere on the same structure. Space Arc typically pairs it with dedicated waterstops at construction joints and pipe penetrations, since the admixture protects the concrete mass itself rather than the joints between pours. Where a project needs surface-applied waterproofing instead of — or in addition to — an integral admixture, MC-Bauchemie’s ombran and other coating ranges cover that scope, and Fosroc’s Brushbond and Proofex ranges are a genuine alternative where a project specification calls for Fosroc.

Related Concrete Admixtures products

View all Concrete Admixtures products →