Fosroc Fosroc® Marine Jacket
A prefabricated fibreglass jacket with an integral zinc mesh anode that repairs and cathodically protects corroding marine piles in tidal and splash zones — no external power required.
What is it?
A prefabricated fibreglass pile jacket lined with an expanded zinc mesh anode that combines structural concrete repair with galvanic (sacrificial) cathodic protection of the embedded reinforcement.
Where is it used?
Corroding reinforced-concrete and structural-steel piles on jetties, piers, wharves and marine berths — particularly in the aggressive tidal and splash zones.
Why use it?
It tackles the root cause of marine pile deterioration — chloride-driven corrosion of the steel — rather than just patching the concrete, delivering a measurable, self-regulating protective current with no power supply.
How is it applied?
The two-piece jacket is fitted around the pile, the zinc mesh is electrically connected to the reinforcement, and the annular gap is filled with a Fosroc-approved grout that reinstates the section and locks the jacket in place.
About Fosroc Fosroc® Marine Jacket
Fosroc Marine Jacket is a pile-rehabilitation system engineered for one of the most punishing service environments in civil engineering — the tidal and splash zones of marine structures. On jetties, piers and berthing structures along India’s long coastline, reinforced-concrete and steel piles are attacked simultaneously by high chloride concentrations, abundant moisture and oxygen, and the mechanical abrasion of waves, silt and debris. This combination drives accelerated corrosion of the embedded steel, which expands as it rusts, cracks and spalls the cover concrete, and progressively reduces the load-carrying capacity of the pile. Conventional patch repairs and surface coatings rarely last in this zone because they do not address the electrochemical corrosion cell that continues to operate beneath the repair. Fosroc Marine Jacket is composed of a prefabricated fibreglass shell lined with an expanded zinc mesh that conforms to ASTM B69-01a for A190 alloy. The zinc mesh is electrically bonded to the steel reinforcement so that it becomes a sacrificial galvanic anode: the zinc corrodes preferentially and supplies a protective current to the steel, halting further section loss. Once the jacket is positioned around the pile, the gap between jacket and substrate is filled with a Fosroc-approved repair grout, which reinstates the lost cross-section and permanently fixes the jacket in place. The system is self-powered and self-regulating — it needs no rectifier, cabling or ongoing power, and it modulates its own output, which avoids the over-protection risk associated with impressed-current systems. Depending on the mesh gauge and bulk-anode selection, a design service life of roughly 10 to 35 years can be specified. Jackets are produced in rectangular, circular, square, flat and fully custom profiles to suit the geometry of almost any pile or column. For Space Arc Engineering’s clients across Delhi NCR and Pan-India — port authorities, marine contractors and asset owners — it offers a durable, monitorable alternative to repeated cosmetic repairs.
The technical insight
The system is a galvanic (sacrificial-anode) cathodic protection (CP) solution, not an impressed-current one. Zinc sits well below steel on the galvanic series, so when the expanded zinc mesh is electrically tied to the reinforcement, an electrochemical cell forms in which the zinc is the anode and the steel becomes the cathode — the steel is therefore protected at the expense of the zinc. The performance benchmark is the NACE RP 0290-90 criterion of a 100 mV potential shift, which the system is designed to satisfy; achieving this shift confirms that corrosion of the steel has been arrested. Because the driving voltage is fixed by the zinc–steel couple rather than an external supply, the current self-regulates with the corrosion demand and the moisture/chloride state of the concrete, eliminating the over-protection and hydrogen-embrittlement concerns that attend impressed-current CP. The fibreglass shell is non-corroding and acts as both formwork for the grout and long-term mechanical protection against abrasion, while the grout annulus restores alkaline, chloride-free cover around the steel — a chemical reset that complements the electrochemical protection. Effective performance depends on a sound, continuous electrical connection between mesh and reinforcement and on full encapsulation of the splash and tidal zones.
Where it is used
- Galvanic cathodic protection of corroding reinforced-concrete marine piles on jetties and piers
- Rehabilitation of structural-steel piles and tubular sections in the splash and tidal zones
- Section reinstatement of spalled, delaminated or chloride-contaminated pile concrete
- Life-extension of berthing structures and wharf piles at ports and container terminals
- Protection of bridge piers and columns founded in brackish or seawater estuaries
- Encapsulation repair of jetty fender piles and dolphin structures
- Corrosion mitigation on coastal industrial intake structures and cooling-water jetties
Key advantages
- Self-powered and self-regulating galvanic system — needs no rectifier, cabling or external power supply
- Designed to meet the NACE RP 0290-90 100 mV potential-shift criterion for verified cathodic protection
- Combines structural concrete repair (grout reinstatement) with corrosion protection in a single operation
- Specifiable design life of approximately 10–35 years depending on mesh gauge and anode selection
- Non-corroding fibreglass shell provides long-term protection against wave and debris abrasion
- Available in rectangular, circular, square, flat and custom profiles to suit any pile geometry
- Performance can be monitored over time using potential measurements
- Avoids the over-protection and hydrogen-embrittlement risks of impressed-current systems
Limitations & considerations
- Galvanic output is finite — the zinc anode is sacrificial and depletes over the design life, after which renewal is required
- Protection depends on a reliable, continuous electrical connection between the zinc mesh and the reinforcing steel
- Sized and shaped per pile — accurate substrate survey and possibly custom fabrication are needed before installation
- Designed for the marine tidal/splash zone; it is not a general above-grade or dry-environment repair product
- Installation in tidal waters requires marine access, working-window planning around tides, and skilled applicators
- Performance relies on correct selection and placement of the Fosroc-approved grout to reinstate the section
- Driving voltage is fixed by the zinc–steel couple, so it suits ongoing protection rather than reviving heavily passivated or fully isolated steel
Selection & best practice
Begin with a condition survey of each pile — map delamination, chloride profiles, cover and half-cell potentials — so jacket size, mesh gauge and bulk-anode selection can be specified against the target service life. Prepare the substrate by removing loose, spalled and severely chloride-contaminated concrete and exposing sound steel where continuity connections are made. Establish and test a reliable electrical bond between the expanded zinc mesh and the reinforcement before grouting, since the entire CP function depends on it. Fit the prefabricated fibreglass jacket, then fill the annulus completely with the specified Fosroc-approved grout, avoiding voids that would leave steel unprotected. Plan installation around tidal windows so the splash/tidal zone is fully encapsulated. After commissioning, record baseline potentials and re-measure periodically to confirm the 100 mV shift is being maintained. Always follow the current Fosroc technical data sheet and method statement, and engage Space Arc Engineering for project-specific design support.
Specifications
| Product Type | Prefabricated pile jacket with integral galvanic anode (cathodic protection + repair) |
| Jacket Material | Prefabricated fibreglass (FRP) shell |
| Anode | Expanded zinc mesh conforming to ASTM B69-01a for A190 alloy |
| Protection Mechanism | Galvanic (sacrificial-anode) cathodic protection — zinc anode bonded to reinforcement |
| Performance Standard | NACE RP 0290-90 — designed to meet the 100 mV potential-shift criterion |
| System Character | Self-powered and self-regulating (no external power source) |
| Design Service Life | Approximately 10–35 years (depending on mesh gauge and bulk-anode selection) |
| Available Profiles | Rectangular, circular, square, flat or custom to suit substrate |
| Infill | Fosroc-approved repair grout (fills annulus, reinstates section, fixes jacket) |
| Primary Substrates | Reinforced concrete and structural steel marine piles |
| Service Zone | Marine tidal and splash zones (high chloride, moisture, oxygen, abrasion) |
Industry use cases
Ports & Harbours
Life-extension of corroding RC berth and wharf piles at container terminals and bulk-cargo jetties, where chloride-induced spalling threatens load capacity and replacement would mean costly downtime.
Coastal Bridges
Protection of bridge piers and pile caps founded in brackish estuaries and seawater, arresting reinforcement corrosion in the splash zone without taking the structure out of service.
Oil, Gas & Power
Rehabilitation of jetty and intake-structure piles at coastal refineries, LNG terminals and thermal/cooling-water installations exposed to seawater and tidal abrasion.
Naval & Defence Marine
Repair and cathodic protection of dockyard, fender and dolphin piles where long maintenance-free intervals are valued and impressed-current infrastructure is impractical.
Fishing Harbours & Minor Ports
Cost-effective reinstatement of deteriorated concrete piles on smaller jetties and landing stages along India’s coastline, extending asset life with a single integrated repair.
Frequently asked questions
Does Fosroc Marine Jacket need an external power supply?
How long does the system last?
How does it protect the steel?
What shapes and pile sizes can it fit?
Does it also repair the damaged concrete?
Where is it best used, and where is it not suitable?
How we position Fosroc Fosroc® Marine Jacket
Fosroc Marine Jacket occupies a specialised niche: it is both a structural pile repair and a galvanic cathodic-protection system for the marine tidal/splash zone, which sets it apart from general concrete-repair mortars. Within the Fosroc range it pairs naturally with the Renderoc repair mortars and Fosroc-approved grouts used for section reinstatement, with Galvashield embedded galvanic anodes (formerly Fosroc Life Jacket / Galvashield LJ) for discrete-anode protection of land-based RC, and with Nitozinc/Nitoprime primers and Dekguard anti-carbonation coatings used elsewhere on marine assets. Compared with competitor approaches, it is a packaged jacket-plus-anode solution rather than a build-up system — alternatives include Sika’s FerroGard galvanic anodes and SikaGrout marine grouts, MBS (MYK/MBCC) repair-and-protection systems, STP (Krishna Conchem) marine protective coatings, and Dr. Fixit repair mortars, though most of these address either the repair or the protection element rather than combining a prefabricated jacket with an integral sacrificial anode in one unit. Space Arc Engineering, as an authorised Fosroc distributor across Delhi NCR and Pan-India, can help asset owners weigh galvanic jacketing against impressed-current CP and conventional patch repair, and specify the correct mesh gauge and grout for the target service life. Selection should always be confirmed against the current Fosroc technical data sheet and a site-specific condition survey.
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