STP ShaliFix MC 65
Free-flowing, non-shrink cementitious micro concrete that pours through congested reinforcement without vibration and climbs to 65-70 MPa — STP’s workhorse for jacketing and formed structural repairs.
What is it?
A single-component micro concrete from STP Limited — a factory blend of Portland cements, graded aggregates, fillers and expansion-control additives that needs only clean water on site.
Where is it used?
Column and beam jacketing, formed repairs in congested reinforcement, parking decks, floor toppings, machine pedestals and pavement reinstatement.
Why use it?
It flows into place without vibration, compensates for plastic-stage shrinkage and settlement, and delivers 28-30 MPa within 24 hours on its way to 65-70 MPa at 28 days.
How is it applied?
Mix a 30 kg bag with 4.5 litres of water, then pour or pump into primed, pre-saturated formwork; extend with 5-12 mm aggregate for sections deeper than 100 mm.
About STP ShaliFix MC 65
When a damaged column or beam has to carry load again, the repair material has to reach every corner of a congested cage — and stay there without shrinking away from the parent concrete. That is the job ShaliFix MC 65 is built for. It arrives as a grey cementitious powder; add 4.5 litres of clean water per 30 kg bag and it turns into a free-flowing micro concrete that pumps or pours into shuttered repairs where a poker vibrator simply cannot go. A gaseous expansion system works while the mix is still plastic, offsetting settlement and shrinkage so the repair stays locked against the substrate and the formwork.
Strength development is genuinely fast: 28-30 MPa in one day, 55-60 MPa by a week, and 65-70 MPa at 28 days — comfortably above most parent concretes it will meet on Indian rehabilitation jobs. For mass pours beyond 100 mm depth, the mix accepts site addition of 5-12 mm graded aggregate to tame heat build-up. Space Arc Engineering stocks ShaliFix MC 65 for Delhi NCR with pan-India project despatch, and our applicator teams can take on jacketing and reinstatement work end to end.
The technical insight
Ordinary site-batched repair concrete fails in two quiet ways: it shrinks as water leaves, opening a gap at the bond line, and it segregates when forced through dense reinforcement. ShaliFix MC 65 attacks both. Its additive package generates a controlled gaseous expansion of 1-4% while the mix is still plastic — exactly the window in which settlement and plastic shrinkage occur — so the material is mildly pressing outwards as it stiffens instead of pulling away. At the same time the blend is engineered around a very low water demand: a water-powder ratio of just 0.15 produces full fluidity because the flow comes from particle grading and admixtures, not extra water. Less mixing water means a denser matrix, which is why the cured repair combines 65-70 MPa strength with low permeability — important where carbonation or chlorides caused the original damage.
Where it is used
- RCC column and beam jacketing on structural strengthening and seismic-retrofit projects
- Formed repairs where congested reinforcement rules out vibration — pumped or poured into restricted access
- Reinstatement of damaged columns, beams and slabs on bridges, flyovers and buildings
- Parking deck and floor topping reinstatement
- Machine and equipment pedestals needing early load transfer
- Rigid pavement patch repairs with quick return to service
- Large-volume repairs deeper than 100 mm, extended on site with 5-12 mm graded aggregate
Key advantages
- Free-flowing — compacts under its own weight, no vibration needed
- Pumpable and pourable into restricted, hard-to-reach repair zones
- Gaseous plastic-state expansion (1-4%) compensates for shrinkage and settlement
- Rapid reinstatement: 28-30 MPa compressive strength within 24 hours
- High ultimate strength of 65-70 MPa with low permeability in the cured repair
- Single component — only clean water added, so batch quality stays consistent on site
- Accepts 5-12 mm aggregate extension for deep or high-volume pours
Limitations & considerations
- It is a pourable material, not a trowel-applied mortar — vertical and overhead patching without formwork calls for a hand-placed mortar such as ShaliFix FRM 70 instead
- Sections deeper than 100 mm need site-added 5-12 mm aggregate to control temperature rise
- The primer or bonding agent (ShaliSBR Latex slurry or ShaliBond Concrete) is not in the bag — order it separately
- Placement is temperature-sensitive: use warm water (up to 30°C) in cold conditions around 15°C, and shade the material with cool mixing water above 35°C ambient
- Mixed material must be placed immediately, so mixer capacity and manpower have to match a continuous pour
- Shelf life is 6 months in unopened bags kept dry — plan procurement accordingly
Selection & best practice
Preparation decides the outcome. Cut back to sound concrete, remove oil, paint and laitance, and mechanically roughen (bush hammer, shot blast or scarifier) to a minimum 3 mm profile exposing coarse aggregate; vacuum or pressure-wash the residue. Saturate the substrate with clean water several hours before the pour and remove standing water, or use a bonding system — a ShaliSBR Latex slurry coat or ShaliBond Concrete epoxy. Coat exposed rebar with ShaliPrime Zn R after cleaning to bright metal. Mix one 30 kg bag with 4.5 litres of water in a forced-action mixer, or a drum with a 400-500 rpm high-torque drill and paddle, for a full 5 minutes; add any specified 5-12 mm aggregate afterwards and mix one more minute. Pour from one side only to avoid trapped air, and start curing immediately after striking formwork — a sprayed curing compound in a continuous film works well.
Specifications
| Compressive strength, 1 day | 28-30 MPa |
| Compressive strength, 7 days | 55-60 MPa |
| Compressive strength, 28 days | 65-70 MPa |
| Flexural strength, 28 days | 6-8 MPa |
| Plastic-state expansion | 1-4% |
| Water : powder ratio | 0.15 (4.5 litres per 30 kg bag) |
| Mixed density | 2.30-2.40 g/cc |
| Pack size | 30 kg bag |
| Shelf life | 6 months, unopened, in cool dry storage |
Industry use cases
Bridges & Metro
Pier and pier-cap jacketing, crash-barrier plinths and deck patch reinstatement on highway and metro rehabilitation packages, where pumpability beats restricted access.
Building Rehabilitation
Column and beam jacketing of corrosion-distressed RCC frames in ageing residential societies and commercial blocks, flowing through added reinforcement without honeycombing.
Industrial Plants
Equipment pedestals, machine foundations and plinth repairs during shutdowns — the 24-hour 28-30 MPa gain shortens downtime windows.
Parking Structures
Deck and ramp topping reinstatement where the low-permeability matrix protects reinforcement from chloride and carbonation attack.
Roads & Pavements
Rigid pavement patch repairs that need early reopening to traffic and a dense, abrasion-resistant surface.
Frequently asked questions
How is micro concrete different from ordinary site-mixed concrete for repairs?
How many bags of ShaliFix MC 65 do I need per cubic metre of repair?
Can I use it for column jacketing with a 50-75 mm annulus?
Will it work on vertical or overhead patches without shuttering?
Do I need a separate bonding agent?
What happens on deep pours beyond 100 mm?
How we position STP ShaliFix MC 65
ShaliFix MC 65 is the flowable, formed-repair member of STP’s ShaliFix range — pair it with ShaliFix FRM 70 or FRM CI for hand-placed vertical and overhead patches, ShaliBond Concrete or ShaliSBR Latex for bonding, and ShaliPrime Zn R for rebar protection, so one system covers the whole repair detail. For precision machine-base grouting rather than structural repair, look at STP’s ShaliGrout line instead. Specifiers standardised on other systems can ask Space Arc about Fosroc Renderoc RG, the closest flowable micro-concrete equivalent we stock.
Fosroc Renderoc RG — A specifier already running Fosroc repair systems, or designing to a 50 N/mm² target, can substitute Renderoc RG for the same pour-or-pump congested-repair duty; choose MC 65 where the design demands the higher 65-70 MPa grade.
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