STP ShaliPatch EC 20
Three-component, cold-applied elastomeric concrete that fills 5-50 mm cracks and spalls on runways, PQC roads and bridge decks — and takes traffic back in as little as two hours.
What is it?
A 3K (resin + hardener + graded aggregate), cold-applied, polymerised elastomeric concrete from STP Limited, formerly sold as ShaliPatch EC, supplied as a pre-proportioned 10 kg kit.
Where is it used?
Cracks 5-50 mm wide and spalled patches on airport runways, aprons and taxiways, PQC roads, bridge decks, parking decks and industrial floors — on both concrete and bituminous pavements.
Why use it?
It cures fast enough to reopen traffic in about 2 hours, yet stays flexible, so the patch absorbs wheel impact and thermal movement instead of cracking out the way rigid mortars often do.
How is it applied?
Saw-cut the repair to a regular shape, clean with dry air, prime concrete with ShaliPrime PUM or 2E SF, mix A+C then B with a spiral paddle, pour into the defect and trowel-finish.
About STP ShaliPatch EC 20
Anyone who maintains concrete pavement in India knows the frustrating cycle: a spall gets patched with a rigid repair mortar, traffic pounds it for a season, and the patch pops out along its own bond line. ShaliPatch EC 20 attacks that failure mode with a different material class altogether — elastomeric concrete. Three components (a polymer resin, a hardener and a graded aggregate) are mixed on site into a self-levelling, 100% solids compound that is simply poured cold into the prepared defect. There is no hot-mix plant, no heating kettle and no compaction equipment involved, which is exactly why the product has found a home on airfield pavements and toll plazas where lane closures are measured in hours, not days.
The formulation, formerly branded ShaliPatch EC, is built for cracks between 5 and 50 mm wide and for surface correction on concrete or flexible roads. Once cured it carries wheel loads — 3 MPa compressive strength within 4 hours, rising to 5 MPa at one day — while retaining roughly 30% elongation, so the patch flexes with the pavement rather than fighting it. Space Arc Engineering supplies the 10 kg pre-weighed kits across Delhi NCR and pan-India, and our applicator teams can take on complete runway and PQC repair packages where reopening time is the critical constraint.
The technical insight
The mechanism worth understanding is the balance between stiffness and strain capacity. A conventional cementitious patch is far stronger in compression than the surrounding pavement needs, but it is brittle: differential thermal movement and repeated impact concentrate stress at the bond line until the patch delaminates. ShaliPatch EC 20 cures to a Shore D hardness of 47 — firm enough that a loaded truck or aircraft tyre will not rut it — yet the polymerised binder still stretches around 30% before failure and passes a falling-weight impact test at -15°C without cracking. Because the system is 100% solids, nothing evaporates during cure, so there is no drying shrinkage pulling the patch away from the saw-cut faces. The graded aggregate (Component C, 5.5 kg of the 10 kg kit) does the load-spreading, while the resin matrix handles adhesion and movement. The trade-off for the rapid ambient cure is a genuinely short pot life — about 10 minutes at 30°C — which is a workflow constraint, not a defect: it is precisely what lets the repair take traffic two hours after pouring.
Where it is used
- Crack filling from 5 mm to 50 mm width in concrete and flexible (bituminous) road pavements
- Patching cracks and spalls on airport runways, aprons and taxiways
- Surface correction and spall repair on PQC roads and bridge decks
- Bedding and reinstatement work when retrofitting airfield runway lighting fixtures
- Ramp and deck patching in multi-level parking structures
- Repair of impact-damaged and spalled industrial floor slabs
- Reprofiling localised surface defects at toll plazas and junctions where rigid patches keep failing
- Repairs that must be sealed over later — the cured material accepts coal tar and asphalt emulsion based sealers
Key advantages
- Minimum traffic reopening time of about 2 hours — lane closures stay short on operational roads and runways
- Elastomeric cured film absorbs thermal movement and wheel impact; passes impact testing at -15°C without cracking
- High early load capacity: 3 MPa compressive at 4 hours, 5 MPa at 1 day (ASTM D 695)
- Bonds to both concrete and bituminous substrates, so one material covers mixed-pavement networks
- Cold-applied and 100% solids — no hot works permit, no heating equipment, no shrinkage from solvent loss
- Self-levelling and trowel-able consistency flows into irregular cracks and spalls with minimal finishing effort
- Strong resistance to fuels, oils, acids, alkalis and saltwater — suited to aprons, fuel bays and coastal roads
- Pre-proportioned 10 kg kit (3.6 kg resin + 0.9 kg hardener + 5.5 kg aggregate) removes site batching errors
Limitations & considerations
- Pot life is only 10 ± 1 minutes at 30°C — crews must prepare all repairs first and mix one kit at a time, especially in Indian summer conditions
- The substrate must be structurally sound and completely dry; standing water or damp pavement rules out application, which limits monsoon-season working windows
- Not a full-depth structural repair — it is designed for 5-50 mm cracks and surface spalls, not failed slabs (use a micro concrete such as ShaliFix MC for those)
- Concrete substrates need priming with ShaliPrime PUM or ShaliPrime 2E SF, adding a material and a waiting step to the sequence
- New concrete must be at least 28 days old before patching, and pavement temperature must not fall below 5°C
- Storage is fussy for cold climates and site containers: the product must not freeze and should be stored between 10°C and 35°C, with a 12-month shelf life unopened
Selection & best practice
Preparation decides whether this patch lasts. Saw-cut the repair area to a regular geometric shape — feather edges are where elastomeric patches get peeled out by tyres. Blow out loose gravel, dust, oil and debris with a jet of dry air; mechanical grinding is acceptable only where sand blasting is not possible. Confirm the surface is dry, the concrete is at least 28 days old, and ambient temperature sits within the 5-35°C application window. On concrete, prime with ShaliPrime PUM or ShaliPrime 2E SF and let it become surface dry. For mixing, stir Component A until uniform, blend A with the Component C aggregate using a slow-speed drill with a spiral bottom-mounted paddle, then add Component B hardener gradually and mix for a full 2-3 minutes. Respect the 10-minute pot life: have the defect ready before the hardener goes in, pour immediately, and trowel-finish the surface. Keep traffic off for a minimum of 2 hours — longer in cold or humid weather — and remember full cure takes about 3 days before maximum chemical exposure.
Specifications
| Composition | 3-component cold-applied elastomeric concrete (A: resin, B: hardener, C: graded aggregate), 100% solids by volume |
| Mixing ratio (A : B : C, by weight) | 3.6 : 0.9 : 5.5 |
| Pot life at 30°C | 10 ± 1 minutes |
| Open to traffic | 2 hours minimum; full cure in 3 days |
| Compressive strength (ASTM D 695) | 3 MPa at 4 hours; 5 MPa at 1 day |
| Tensile strength, 7 days (ASTM D 412) | 1.3 ± 0.07 MPa with 30 ± 2% minimum elongation |
| Hardness (ASTM D 2240) | Shore D 47 ± 3 |
| Application temperature | 5°C to 45°C (keep ambient within 5-35°C at time of placement) |
| Pack size | 10 kg kit: Component A 3.6 kg + Component B 0.9 kg + Component C 5.5 kg |
Industry use cases
Airports
Runway, apron and taxiway spall repairs between flight operations, plus bedding around retrofitted runway lighting — the 2-hour reopening and fuel resistance are decisive on airside pavements.
Highways & PQC Roads
Crack filling from 5 to 50 mm and surface correction on concrete carriageways and toll plazas where rigid patches have repeatedly debonded under fast, heavy traffic.
Bridges & Flyovers
Deck spall patching and localised repairs near joints, where the elastomeric matrix tolerates deck flexure and thermal cycling that would crack a cementitious repair.
Industrial Plants
Forklift-trafficked floor patches in warehouses, loading bays and process areas exposed to oils, fuels and chemical spillage, with shifts resuming the same day.
Parking Structures
Ramp and deck defect repair in commercial and residential parking, where cold application indoors avoids hot-work permits and ventilation headaches.
Frequently asked questions
How quickly can we reopen the lane to traffic?
Does it work on bituminous roads or only concrete?
What crack sizes can it handle?
How much area does a 10 kg kit cover?
How do we manage the 10-minute pot life on a hot site?
What is the difference between ShaliPatch EC 10 and EC 20?
How we position STP ShaliPatch EC 20
ShaliPatch EC 20 sits in STP’s pavement repair family, and it rarely travels alone: concrete repairs need ShaliPrime PUM or ShaliPrime 2E SF as the primer, ShaliPatch EC 10 covers the alternate elastomeric grade, and where the defect turns out to be structural rather than superficial, ShaliFix MC micro concrete handles full-depth reinstatement. For rigid PQC or industrial-floor patches where movement accommodation is not required, many specifiers standardise on Fosroc Patchroc GP instead — a rapid-hardening cementitious patch mortar that we also stock and apply. Space Arc supplies both brands ex-stock across Delhi NCR with pan-India dispatch, so the choice can be made on engineering merit, not availability.
Fosroc Patchroc GP — Specifiers pick Patchroc GP when the repair is in rigid concrete with no movement demand and they want a cementitious, rapid-reopening patch mortar that matches the parent slab rather than an elastomeric system.
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