MC-Bauchemie MC-Grout 500
An ultra-fine, microfine cement injection grout milled to penetrate hairline cracks and tight rock fissures that ordinary grouts cannot reach.
What is it?
A microfine cementitious injection grout from MC-Bauchemie, milled 4 to 6 times finer than ordinary Portland cement so it flows into cracks and fissures as narrow as 0.05 to 0.08 mm.
Where is it used?
Post-tensioning cable ducts, dam curtain grouting, tunnel rock stabilisation, prestressed concrete crack injection and heritage masonry consolidation.
Why use it?
Its 8,000 to 12,000 cm2/g Blaine fineness lets a stable, non-bleed cement suspension travel where micro-fine penetration decides whether the void actually fills.
How is it applied?
Batched in a colloidal mixer at a 0.40 to 0.50 water-solid ratio and injected through a piston or diaphragm pump, typically at 0.5 to 3 bar.
About MC-Bauchemie MC-Grout 500
MC-Grout 500 is MC-Bauchemie’s answer to a problem that trips up conventional grouting on Indian sites: when the target is a hairline crack, a tight rock joint or a partially blocked post-tensioning duct, ordinary Portland cement simply will not go in. Its particles are too coarse to enter the opening and they filter out at the mouth, leaving the void behind them empty. MC-Grout 500 is a specially milled blend of Portland cement and supplementary materials ground to a Blaine fineness of 8,000 to 12,000 cm2 per gram, roughly four to six times finer than the cement most crews are used to. With a maximum particle size of D100 below 16 microns and D95 below 12 microns, the suspension behaves less like a slurry and more like a fluid that can thread into openings of 0.05 to 0.08 mm.
For engineers and consultants working on bridges, dams and tunnels, that fineness is the whole point. It is the difference between a grouting record that reads well and a void that quietly stays hollow behind the gauge. Because MC-Grout 500 is engineered for penetrability, it is formulated to stay stable in suspension long enough to travel, with low bleed and a controlled thickening window rather than the rapid segregation that coarse cement shows once it is thinned. On post-tensioned road bridges the product is positioned to meet the injection requirements that Indian specifications lay down for duct grouting, while on rock and masonry work it is the tool a specialist reaches for when the alternative is chemical resin at many times the cost.
The technical insight
The mechanism is entirely about particle size relative to aperture. A grout can only enter an opening roughly three times its largest particle before bridging occurs and the flow chokes at the entry. Ordinary Portland cement, with particles up to 40 to 90 microns, bridges across anything below about a quarter of a millimetre, so injection pressure just builds without penetration. MC-Grout 500 shifts that limit down: with D100 under 16 microns it can thread into 0.05 to 0.08 mm cracks, filling voids that coarser cement can only seal at the surface. The extreme surface area from the 8,000 to 12,000 cm2/g fineness makes the fresh mix cohesive and low-bleed, so the suspension carries its solids the full travel distance instead of the water running ahead and the cement dropping out. At a 0.45 water-solid ratio it develops a minimum of 25 MPa at 28 days, and its Marsh cone viscosity of 14 to 25 seconds with a thickening time of at least 30 minutes gives a real injection window before the mix stiffens. That combination, fine enough to enter, stable enough to travel, strong enough to stay, is what lets a microfine grout do work that neither ordinary cement nor a low-viscosity resin does as economically.
Where it is used
- Grouting of post-tensioning cable ducts in bridges and buildings where partial blockage or fine annular gaps defeat ordinary cement grouts
- Curtain and consolidation grouting of fissured rock foundations beneath dams and hydraulic structures
- Pre-excavation rock stabilisation ahead of tunnel boring, treating tight joints in advance of the face
- Injection of micro-cracks in prestressed and precast concrete elements to restore monolithic behaviour
- Consolidation grouting of historic and heritage masonry where only low-pressure, fine penetration is acceptable
- Void filling behind segmental tunnel linings to eliminate annular gaps against the surrounding ground
- Sealing of seepage paths and fine fissures in concrete and rock where water ingress must be cut off
- Densification of loose or micro-fissured ground where chemical resins would be uneconomical
Key advantages
- Microfine particle grading (D100 below 16 microns) penetrates cracks down to 0.05 to 0.08 mm that ordinary cement cannot enter
- Blaine fineness of 8,000 to 12,000 cm2/g, four to six times finer than OPC, for genuine deep penetration
- Low bleed, below 0.5 percent at design water-solid ratio, so the suspension stays stable over the injection travel
- Adjustable 0.40 to 0.50 water-solid ratio lets the crew tune fluidity to the aperture and pressure on hand
- Marsh cone viscosity of 14 to 25 seconds with a workable 30 to 60 minute injection window
- Cement-based chemistry gives durable, compatible hardened grout without the cost or handling of resin systems
- Formulated to meet Indian post-tensioning duct-grouting requirements for bridge work
- Injectable at low pressure (0.5 to 3 bar), suitable for pressure-sensitive heritage and masonry work
Limitations & considerations
- A cementitious grout still cannot enter openings finer than roughly 0.05 mm; genuinely sub-micron seepage may need a chemical resin instead
- Penetration depends on correct colloidal mixing; a paddle mixer will not disperse the microfine particles fully and performance suffers
- The 30 to 60 minute injection window means the mix must be pumped promptly, with no long standing time before injection
- Compressive strength (minimum 25 MPa at 28 days) is lower than structural repair micro-concretes and it is not a load-bearing bedding grout
- Water-solid ratio and injection pressure must be matched to the aperture; over-thin or over-pressurised injection risks bleed or further damage in fragile substrates
- Being a specialist microfine product, cost per bag is higher than ordinary cement grout, so it is justified only where fine penetration is actually required
Selection & best practice
Start by matching the grout to the aperture: for cracks or joints in the 0.05 to 0.15 mm range, use the leaner end of the 0.40 to 0.50 water-solid range for stability, and thin only if penetration stalls. Always disperse in a high-shear colloidal mixer, never a slow paddle, because incomplete dispersion leaves agglomerates that behave like coarse cement and bridge at the crack mouth. Check consistency with a Marsh cone, aiming inside the 14 to 25 second band, and mix only what can be injected inside the 30 to 60 minute window. Inject at low, progressively raised pressure, typically 0.5 to 3 bar, and hold to the lower pressures on heritage masonry or thin prestressed sections where high pressure can propagate the very cracks you are filling. For post-tensioning ducts, verify duct condition and vent arrangement first, and grout to refusal at each outlet in sequence. Keep the substrate saturated but surface-dry so it neither drinks water from the grout nor dilutes it, and record injection volumes against theoretical void to confirm the fill.
Specifications
| Product type | Ultra-fine microfine cementitious injection grout |
| Blaine fineness | 8,000 to 12,000 cm2/g (4 to 6 x finer than OPC) |
| Maximum particle size | D100 below 16 microns; D95 below 12 microns |
| Crack penetrability | 0.05 to 0.08 mm (50 to 80 microns) |
| Water-solid ratio | 0.40 to 0.50 (design range) |
| Compressive strength | Minimum 25 MPa at 28 days (w/s 0.45) |
| Bleed | Less than 0.5 percent at design water-solid ratio |
| Marsh cone viscosity | 14 to 25 seconds at design w/s ratio |
| Injection window / pressure | 30 to 60 min injectable; 0.5 to 3 bar typical |
Industry use cases
Bridges & PT structures
Grouting post-tensioning cable ducts where fine annular gaps or partial blockages leave ordinary cement grout stranded at the inlet, protecting the tendon from corrosion.
Dams & hydraulic works
Curtain and consolidation grouting of fissured rock foundations, sealing fine seepage joints that coarser cement suspensions cannot enter.
Tunnelling
Pre-excavation rock stabilisation and annular void filling behind lining segments, treating tight joints ahead of and around the bore.
Heritage & masonry
Low-pressure consolidation of historic masonry, penetrating fine internal voids without the high injection pressures that would damage fragile fabric.
Precast & prestressed repair
Injection of micro-cracks in prestressed and precast elements to restore monolithic load transfer where resin would be uneconomical.
Frequently asked questions
How is MC-Grout 500 different from ordinary cement grout?
What is the finest crack MC-Grout 500 can actually fill?
What water-solid ratio and strength should I expect?
Can I mix it with a normal drum or paddle mixer?
Is it suitable for post-tensioning duct grouting on bridges?
Does Space Arc supply MC-Grout 500 across India and offer application support?
How we position MC-Bauchemie MC-Grout 500
MC-Grout 500 sits at the specialist end of the grouting shelf and is chosen specifically for microfine penetration into hairline cracks, tight rock joints and partially blocked ducts. Where the job is ordinary bed grouting, machine-base grouting or non-shrink pocket filling with standard cement, look instead to a flowable cementitious grout or to an expansion admixture that upgrades site-batched cement grout. For high-strength precision bedding under base plates, a ready-to-use non-shrink grout is the right tool rather than a microfine injection grout. Across our other brands, engineers often pair microfine injection work with matching PU or acrylic injection resins for sub-0.05 mm seepage that cement cannot reach, and with surface crack-sealing and duct-venting accessories from the Fosroc and Sika ranges we stock. Talk to us about the aperture, the pressure limit and the substrate, and we will point you to the correct grout rather than the most expensive one.
Fosroc Cebex 300 — Specify Cebex 300 when the work is standard post-tensioning duct or bed grouting using ordinary site-batched cement, rather than microfine penetration into hairline cracks and tight rock fissures where MC-Grout 500’s ultra-fine grading is essential.
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