Master Builders Solutions MasterRoc MP 368
A fast-reacting polyurea silicate injection resin from Master Builders Solutions, built to consolidate fractured rock and coal strata and cut off water and gas underground.
What is it?
A two-component, fire-resistant polyurea silicate injection resin that reacts within minutes to consolidate fractured rock, coal and cracked concrete.
Where is it used?
Tunnel and metro headings, underground coal mine roadways and longwalls, hydropower and irrigation tunnels, and below-grade structures needing fine-crack water sealing.
Why use it?
It penetrates fractures down to 0.14 mm, reaches 5 MPa bond strength in 30 minutes, and neither expands against water nor absorbs it — properties ordinary cementitious grout can’t match underground.
How is it applied?
Part A and Part B are pumped at a 1:1 volume ratio through a two-component injection pump fitted with a roughly 32 cm static in-line mixer, into boreholes drilled to the target strata.
About Master Builders Solutions MasterRoc MP 368
MasterRoc MP 368 sits apart from the cementitious and epoxy grouts that fill most construction-chemicals catalogues. It is a two-component, solvent-free polyurea silicate injection resin from Master Builders Solutions, built for ground consolidation in tunnels, mines and underground structures. Part A is a colourless, low-viscosity liquid; Part B is a dark brown reactive component; both are metered 1:1 by volume through an injection pump with a static in-line mixer, into boreholes drilled into fractured rock, loose coal seams or cracked concrete. The resin gels within roughly 90 seconds of leaving the mixer and sets in about two and a half minutes, giving a working bond strength of 5 MPa in half an hour.
For Space Arc, MP 368 is a specialist line rather than a shelf item. It ships in project quantities — Part A in 36 kg cans or 298 kg drums, Part B in 28 kg cans or 232 kg drums — and earns its place where ordinary grout can’t reach a fine fracture or react fast enough. Its fire-resistant, non-foaming chemistry (foam expansion factor of 1, so it doesn’t swell against water) directly answers underground coal environments where gas and water control matter. We position it for engineers and contractors on metro tunnel headings, hydropower tunnels, coal mine roadways and rock-stabilisation contracts who already know they need a consolidation-grade injection resin.
The technical insight
The number worth remembering on MP 368 is 0.14 mm — the datasheet states it penetrates fractures down to that width, finer than most cement or epoxy grouts reach without heavy dilution. That comes from the low viscosity of both parts (300 mPa.s for Part A, 115 mPa.s for Part B at 23°C), not pumping pressure alone. The 1:1 ratio and ~90-second flow time make the static mixer length (about 32 cm) a real variable: get it wrong and the components arrive only partly reacted, undermining the 25 MPa compressive strength and 5 MPa bond figures it’s specified for. Ground temperature below +5°C is the other real constraint — the reaction slows enough that cure time becomes unpredictable, which is why +5°C to +35°C storage is a requirement, not a suggestion.
Where it is used
- Consolidation grouting of fractured rock in tunnel headings and metro drives
- Coal seam consolidation in underground development roadways and longwalls
- Curtain and contact grouting against water and gas ingress underground
- Injection repair of concrete cracks and joints down to 0.14 mm wide
- Pre-treatment of loose or fractured ground ahead of TBM and NATM excavation
- Emergency water cut-off grouting in active mine roadways and tunnels
- Consolidation around rock bolts and support elements in unstable strata
Key advantages
- Reacts fast even in cold, damp underground conditions, mixing well above +5°C
- Reaches 5 MPa bond strength in 30 minutes so work resumes quickly
- Builds compressive strength over 25 MPa within 24 hours
- Neither expands against water nor absorbs it, keeping treated ground stable
- Penetrates fine fractures down to 0.14 mm that most cement grouts can’t enter
- Fire-resistant formulation suited to underground coal mining safety needs
- Simple 1:1 by volume mixing ratio simplifies metering on injection pumps
Limitations & considerations
- Needs a dedicated injection pump and trained crew, not hand-mixing on site
- Sold only in project quantities (28–298 kg packs), not retail repair packs
- Performance is rated at 23°C; below +5°C, cure time is unpredictable
- The manufacturer’s TDS doesn’t cite IS, BS or EN compliance — request project certification separately
- Being non-foaming, it won’t bulk-fill large voids like an expanding PU foam
Selection & best practice
Condition both components to at least +5°C before pumping — figures are rated at 23°C and slow markedly in cold ground. Use a metering pump with a static in-line mixer of roughly 32 cm and confirm 1:1 delivery on a test hole before production boreholes. Plan spacing and pressure against the project’s geotechnical grouting design rather than by feel. Between breaks, pump Part A alone through the nozzle and mixer; at shift end, flush the pump and hoses with MasterRoc MP 230 CLN or a water-free oil until fully washed out, then store with the cleaning agent inside. Keep drums sealed, off wet ground, within +5°C to +35°C to protect the 24-month shelf life, and use gloves, eye protection and protective clothing as standard.
Specifications
| Chemistry / system | Two-component, solvent-free, fire-resistant polyurea silicate injection resin |
| Mixing ratio (Part A : Part B) | 1 : 1 by volume |
| Density @23°C | Part A 1.49 kg/dm³ (colourless); Part B 1.16 kg/dm³ (dark brown) |
| Viscosity @23°C | Part A 300 mPa·s; Part B 115 mPa·s |
| Flow time @23°C | 90 s ± 30 s |
| Setting time @23°C | 2 min 30 s ± 30 s |
| Bond strength | 5.0 MPa at 0.5 h |
| Compressive strength | >25 MPa at 24 h |
| Pack sizes / shelf life | Part A: 36 kg cans, 298 kg drums; Part B: 28 kg cans, 232 kg drums; 24-month shelf life (+5°C to +35°C, dry storage) |
Industry use cases
Metro & rail tunnelling
Consolidation grouting of fractured rock ahead of NATM or TBM headings on urban tunnel drives
Underground coal mining
Strata consolidation and water/gas sealing in development roadways and longwall faces
Hydropower & irrigation tunnels
Curtain grouting to control seepage through fissured rock in headrace and tailrace tunnels
Below-grade waterproofing repair
Crack injection in basements, lift pits and diaphragm walls facing active water ingress
Underground caverns & shafts
Pre-treatment of loose strata before permanent rock support installation
Frequently asked questions
Is this the same as a normal cementitious or epoxy anchor grout?
What equipment does applying it need?
Can it be injected into wet ground?
How soon can work resume after injection?
What’s the shelf life and storage requirement?
Will Space Arc supply this for a one-off crack repair?
How we position Master Builders Solutions MasterRoc MP 368
MP 368 belongs to Master Builders Solutions’ MasterRoc range for tunnelling and ground engineering, normally specified alongside MasterRoc MP 230 CLN, the water-free agent named for flushing injection pumps — the two are a working pair on site. It also sits near MasterRoc’s rock-bolting resins and sprayed-concrete accelerators in the same underground-works portfolio. Fosroc, the alternative most Indian specifiers reach for first, doesn’t carry a direct polyurea silicate ground-consolidation resin; its strength is cementitious and epoxy anchor grouts such as Conbextra, built for machine-base and rebar anchoring in dry conditions, not injecting fractured rock under active water ingress. For fine crack water-stopping rather than full rock consolidation, engineers sometimes compare MP 368 against Sika’s injection resin range instead.
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