STP ShaliFix SC 40
A single-component, rapid-setting Portland-cement repair mortar that puts damaged roads, floors and structures back into service in hours, not days.
What is it?
A one-part, ready-to-use Portland-cement repair mortar from STP that needs only clean water on site to produce a non-shrink, rapid-setting, high-strength patch.
Where is it used?
Roads, parking decks, bridges, dam faces, industrial and turbine floors, balconies, terraces and spalled concrete members across Delhi NCR and pan-India projects.
Why use it?
It hardens fast enough to reopen traffic quickly, reaches 58 to 65 MPa at 28 days, and carries no chlorides that could corrode the parent structure.
How is it applied?
Prime the saturated, cleaned substrate with an SBR-latex cement slurry, mix the powder at 0.14 to 0.15 water-to-powder, then trowel or press the mortar into the repair and cure normally.
About STP ShaliFix SC 40
STP ShaliFix SC 40 is the kind of product a site engineer reaches for when a repair cannot wait. It arrives as a grey powder in a single 30 kg bag, and the only thing the crew adds is clean water. That simplicity matters on a live site: there is no second component to measure, no resin to blend, and no risk of getting the ratio wrong in a hurry. Once mixed, it behaves as a non-shrink, quick-setting mortar that bonds tightly to sound concrete and masonry and develops strength quickly enough to take load or traffic the same working shift.
What separates SC 40 from an ordinary sand-cement patch is the balance it strikes between speed and durability. Many fast-setting products buy their early strength at the cost of long-term performance or shrinkage cracking. SC 40 sets in roughly 40 to 50 minutes yet still climbs to 58 to 65 MPa in compression at 28 days, with low permeability that keeps water and chlorides out of the repair. Because the formulation carries no chlorides or corrosion-promoting additives, it is safe to place directly against reinforcement and around embedded steel, which is exactly where cheaper repair mixes tend to cause trouble down the line.
The technical insight
The performance comes from a carefully graded Portland-cement system that is engineered to hydrate quickly while compensating for the shrinkage that normally accompanies fast setting. At a tight water-to-powder ratio of 0.14 to 0.15, the mix stays dense and low in capillary porosity, which is why permeability under DIN 1048-5 stays below 15 mm and why the mortar keeps aggressive water away from the substrate. The rapid strength curve is deliberate: roughly 13 to 18 MPa within two hours, 25 to 30 MPa at 24 hours, and 40 to 50 MPa by seven days. That early load-bearing capacity is what allows a road or shop floor to reopen within the same shift instead of being fenced off for a week. The non-shrink behaviour ensures the patch stays keyed into the surrounding concrete rather than debonding at the edges as it cures, and the SBR-latex slurry priming step creates a bonding bridge that locks the new mortar to the old surface.
Where it is used
- Structural repair of roadways, parking lots, warehouses, bridges, dams, machinery bases and turbine floors
- Patching damaged or spalled concrete in balconies, terraces, walls and beams
- Repair of spalling and cover loss over exposed reinforcement
- Reinstatement of industrial and shop-floor surfaces subject to quick return to service
- Horizontal road repairs, manhole placement, and bedding and bonding of road furniture
- Joint and pavement nosing where a hard, fast-curing edge is needed
- Grouting of pavement stone and joint filling in paved areas
- Anchoring and fixing of road signage and street furniture
Key advantages
- Rapid hardening and return to service, sharply reducing downtime on live sites
- Single-component powder that needs only clean water, so no batching or ratio errors
- Reaches high compressive strength of 58 to 65 MPa at 28 days for durable repairs
- Non-shrink behaviour keeps the patch keyed to the substrate without edge debonding
- Contains no chlorides or corrosion-promoting additives, safe around reinforcement
- Low permeability under DIN 1048-5 gives higher durability against water ingress
- Works even at lower temperatures, allowing rapid reopening to traffic
- Easy trowel application, with tools cleaned by water before the mortar hardens
Limitations & considerations
- Very short working window: the entire mixed batch must be placed within about 5 minutes, so only mix what a crew can use immediately
- Requires a separate SBR-latex slurry priming coat for reliable bond, adding a step to the sequence
- Not a flowable micro-concrete, so it suits trowel-applied patches rather than pouring into congested formwork or deep pockets
- Shelf life is only 6 months from manufacture, and stock must be kept dry and out of heat
- Sensitive to storage; tropical or humid conditions call for air-conditioned storage to avoid premature deterioration
- As a rigid cementitious mortar it is not designed to accommodate moving cracks or expansion joints
Selection & best practice
Success with SC 40 is mostly about preparation and pace. Cut cracks or holes back to a minimum width and depth of around 20 mm with square edges, remove all dust, oil, grease and curing compound, and saturate the substrate with clean water for several hours before placing, removing any standing water just before you start. Prime with ShaliSBR latex-modified cement slurry mixed roughly 1:2 to a brushable consistency so the fresh mortar bonds into a tacky primer rather than a dry surface. Mix the powder in a mortar mixer at a water-to-powder ratio of 0.14 to 0.15 until homogeneous, and treat the batch as perishable: place, trowel and press it into the repair within about 5 minutes, then follow normal mortar curing. Because the pot life is so short, keep batches small and match mixing to placing capacity rather than mixing a full bag at once.
Specifications
| Product type | Single-component, ready-to-use Portland-cement repair mortar (1K) |
| Appearance | Grey powder in a single-pack system |
| Water to powder ratio | 0.14 to 0.15 (adjust for consistency and climate) |
| Setting time | 40 to 50 minutes |
| Workable time | 10 to 12 minutes |
| Compressive strength (ASTM C 109) | 13-18 MPa at 2 hrs; 25-30 at 24 hrs; 40-50 at 7 days; 58-65 at 28 days |
| Tensile / flexural strength at 28 days | Tensile > 2.5 MPa; flexural > 7 MPa |
| Permeability (DIN 1048-5) | < 15 mm at 28 days |
| Packaging | 30 kg moisture-resistant bags (yield approx. 0.0136 m3 per bag) |
Industry use cases
Highways and roads
Overnight patching of potholes, joint nosing and manhole surrounds so lanes can be reopened to traffic before the morning peak.
Industrial and warehousing
Reinstating spalled or worn shop-floor and turbine-floor areas during short maintenance windows without extended plant shutdowns.
Bridges and infrastructure
Repairing spalled cover and damaged concrete on decks, kerbs and structural members where rapid strength gain and low permeability matter.
Buildings and facades
Fixing damaged concrete in balconies, terraces, beams and walls where a fast, non-shrink, chloride-free patch protects embedded steel.
Urban works and street furniture
Bedding paving stone, filling joints and anchoring road signage and street fixtures with a hard, quick-setting mortar.
Frequently asked questions
How quickly can a repair take traffic or load?
Do I need to prime the surface before applying it?
What is the working time once mixed?
Is it safe to use against reinforcement?
What pack size and coverage should I plan for?
How should it be stored and how long does it last?
How we position STP ShaliFix SC 40
ShaliFix SC 40 sits at the fast-turnaround end of STP’s Restofix repair range and is best chosen when speed of return to service is the priority. Where a repair needs to flow into congested reinforcement or deep formwork, step across to STP’s micro-concrete grades such as ShaliFix MC or MC 65; where corrosion protection over exposed steel is the main concern, ShaliFix FRM CI adds a corrosion-inhibiting, fibre-reinforced option, and FRM 40, 50 and 70 cover polymer-modified structural repairs at increasing strength. Pair SC 40 with ShaliSBR latex as the bonding primer to get the specified adhesion. Across our other brands, engineers comparing options often look at Fosroc’s Renderoc family or Sika’s MonoTop repair mortars for equivalent single-component patching, and Space Arc can supply and advise across all of them.
Fosroc Renderoc GP — A specifier may prefer Renderoc GP when a single-component, shrinkage-compensated mortar is needed for vertical and overhead reprofiling rather than SC 40’s fast horizontal, road and floor repairs.
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