Fosroc Life Jacket
Prefabricated GRP jacket with an integral zinc sacrificial-anode mesh that repairs and cathodically protects severely exposed marine and splash-zone reinforced concrete in a single operation.
What is it?
A two-piece, tongue-and-groove GRP (fibreglass) jacket lined with an expanded zinc anode mesh that provides galvanic cathodic protection to corroding reinforcement, supplied prefabricated to the structure’s profile.
Where is it used?
Marine and tidal/splash-zone reinforced-concrete piles, jetties, wharves, bridge sub-structures and other severely exposed RC elements where chloride-induced reinforcement corrosion is active.
Why use it?
It combines structural concrete repair and long-term sacrificial corrosion protection in one self-powered system, avoiding the cost and maintenance of impressed-current cathodic protection.
How is it applied?
Deteriorated concrete is broken out and steel cleaned; the prefabricated jacket is clamped around the element with non-conductive fasteners, electrically connected to the steel, and the annulus is poured with Renderoc LJ conductive repair grout.
About Fosroc Life Jacket
Fosroc Life Jacket, previously marketed as Galvashield LJ, is a galvanic (sacrificial-anode) cathodic protection and repair system engineered specifically for the harshest service environment a concrete structure faces: the tidal and splash zones of marine and coastal infrastructure. Rather than being a coating or a mortar in the conventional sense, it is a prefabricated composite jacket. Each unit is a two-piece GRP (glass-reinforced polyester) shell with an interlocking tongue-and-groove joint, internally lined with an expanded zinc mesh that acts as the sacrificial anode. Once the jacket is clamped around a pile or column and electrically tied to the reinforcing steel, the zinc preferentially corrodes in place of the embedded steel, halting the chloride-driven corrosion that causes spalling, cracking and section loss.\n\nWhat makes the system distinctive in the Indian context is that it solves repair and protection together. Across India’s long coastline — from the container terminals of Mumbai, Mundra and Chennai to the jetties of Kochi, Visakhapatnam and the Andaman ports — RC piles in seawater suffer relentless chloride attack. Conventional patch repair alone often fails within a few years because the new, high-pH repair mortar sets up a fresh corrosion cell (the incipient-anode or ‘ring-anode’ effect) around the patched area. Fosroc Life Jacket addresses this directly: the zinc anode keeps the whole protected length cathodic, so the repair is not undermined by renewed corrosion at its edges. The cavity between the jacket and the substrate is filled with Renderoc LJ, a conductively compatible high-strength repair grout supplied by Fosroc to guarantee electrical continuity between anode and steel.\n\nThe system is ‘self-powered’ — it generates its own protective current from the galvanic potential difference between zinc and steel, with no external power supply, transformer-rectifier or wiring infrastructure. The current output naturally regulates itself according to the corrosion rate and the operating environment (temperature, moisture, chloride level), rising when the steel is most at risk and tapering when conditions are benign. A standard junction box houses the wire connections and provides a point at which the circuit can be opened to measure current and potential, allowing the structure’s corrosion state to be monitored over its service life. For Space Arc Engineering’s clients — port authorities, marine contractors, and asset owners across Delhi NCR and pan-India project sites — it represents a durable, low-intervention alternative to impressed-current cathodic protection (ICCP), which demands ongoing power, control panels and specialist maintenance.
The technical insight
The protection mechanism is classic galvanic coupling. Zinc sits well above iron in the galvanic series, so when the expanded zinc mesh (an ASTM B69 A190-alloy anode) is electrically connected to the reinforcing steel through the conductive Renderoc LJ matrix and seawater electrolyte, a self-driving cell is formed. Zinc becomes the anode and dissolves sacrificially, driving a small protective current to the steel which becomes the cathode and is thereby preserved. Crucially, the design targets the NACE Standard RP 0290-90 criterion of a minimum 100 mV potential shift — the recognised benchmark for effective cathodic protection — confirming that the steel is genuinely depolarised rather than merely patched. The jacket geometry matters as much as the chemistry: the lower annulus is left open via removable formwork after the structural grout is poured, so that saltwater can continue to migrate in and wet the anode interface. This sustained electrolyte contact is what keeps the cell active in the tidal zone, where wet-dry cycling would otherwise throttle a buried anode. The result is a system that, per Fosroc, exceeds the minimum 15-year design-life criterion of FHWA/DOT specifications, with the option to extend life further by adding bulk anodes.
Where it is used
- Repair and galvanic cathodic protection of chloride-contaminated RC marine piles in tidal and splash zones
- Rehabilitation of jetty, wharf and pier sub-structures suffering reinforcement corrosion and spalling
- Protection of bridge piers, pile caps and abutments in coastal or brackish-water exposure
- Columns and structural steel elements in severely aggressive saline environments
- Service-life extension of port and harbour infrastructure as an alternative to impressed-current CP
- Arresting the incipient-anode (ring-anode) effect around previous concrete patch repairs
Key advantages
- Combines structural concrete repair and long-term corrosion protection in a single installation operation
- Self-powered galvanic system needs no external power, rectifiers or control panels, unlike ICCP
- Output current self-regulates to the corrosion rate and environment, giving demand-responsive protection
- Prefabricated to project dimensions, so installation is fast and repeatable on multiple piles
- Suppresses the incipient-anode effect that causes conventional patch repairs to fail at their edges
- Junction box allows ongoing monitoring of current and potential to verify performance
- Designed to exceed a 15-year service life, extendable with supplementary bulk anodes
- Minimal post-installation maintenance compared with powered cathodic protection systems
Limitations & considerations
- Requires electrically continuous reinforcement; continuity must be established across the structure before connection
- Effective only where the anode interface stays wetted by saltwater/electrolyte — best suited to marine, tidal and splash-zone exposure rather than dry indoor elements
- Zinc is consumed sacrificially, so protection has a finite life and the anode is eventually depleted
- Must be filled with the matched conductive grout (Renderoc LJ) from the same supplier to guarantee electrical compatibility
- As a prefabricated jacket it suits regular pile/column profiles; highly irregular geometries need custom fabrication
- Installation involves break-out, steel cleaning to bright metal and underwater/tidal access — specialist marine repair contractors are needed
- Not a general-purpose concrete repair mortar or a substitute for waterproofing in non-saline environments
Selection & best practice
Establish reinforcement continuity across the element before anything else — measure resistance between bars and bond any discontinuities, because a galvanic system protects only steel it is electrically connected to. Saw-cut repair perimeters to at least 10 mm depth to avoid feather edges, break out all delaminated concrete from around and behind the bars, and abrasive-blast the exposed steel to a bright condition, paying particular attention to the rear face of the bars. Make the negative connection to sound steel through a single excavation in compliance with the specification, and route all wiring to a junction box for future monitoring. Fill the jacket annulus only with Renderoc LJ to preserve anode-to-steel conductivity, retain temporary formwork at the lower annulus during the pour, then remove it so saltwater can wet the anode interface. Commission the system by confirming the 100 mV potential shift (NACE RP 0290-90) and record baseline current/voltage at the junction box for the asset’s monitoring file.
Specifications
| Product type | Prefabricated galvanic (sacrificial-anode) cathodic protection and repair jacket |
| Former designation | Galvashield LJ |
| Jacket construction | Two-piece GRP (glass-reinforced polyester / fibreglass) shell with tongue-and-groove interlocking joint |
| Anode material | Expanded zinc mesh conforming to ASTM B69-01a, A190 alloy |
| Protection mechanism | Self-powered galvanic cathodic protection; current self-regulates to environment |
| Repair grout (annulus fill) | Renderoc LJ conductively compatible high-strength repair material |
| Cathodic protection criterion | Meets minimum 100 mV potential shift per NACE Standard RP 0290-90 |
| Design life | Exceeds 15-year minimum criterion (FHWA / DOT specifications); extendable with bulk anodes |
| Fasteners | Non-conductive fasteners; moisture-tight seal with approved adhesive |
| Monitoring | Standard junction box for current and voltage measurement |
| Minimum saw-cut depth at repair edge | 10 mm (to avoid feather edging) |
| Available profiles | Rectangular, circular, square, flat or custom formats; supplied prefabricated to project dimensions |
| Health & safety | No known hazards associated with the jacket; refer to Renderoc LJ TDS for grout |
Industry use cases
Ports & Harbours
Rehabilitating corroding RC fender and berth piles at container and bulk terminals along the Indian coast, extending service life without taking the berth fully out of operation for ICCP installation.
Marine & Offshore
Protecting jetty and wharf sub-structures in the tidal/splash zone where chloride ingress and wet-dry cycling drive the most aggressive reinforcement corrosion.
Bridges & Coastal Infrastructure
Arresting corrosion in piers, pile caps and abutments of sea-crossing and estuary bridges, where the 100 mV NACE criterion provides documented, monitorable protection.
Asset Owners & Port Authorities
Adopting a low-maintenance, self-powered alternative to impressed-current CP, with junction-box monitoring that fits long-term structural health and life-cycle costing programmes.
Frequently asked questions
Is Fosroc Life Jacket the same as Galvashield LJ?
How does it protect reinforcement without electricity?
How is it different from impressed-current cathodic protection (ICCP)?
What is the design life of the system?
Which grout must be used to fill the jacket?
Where is Fosroc Life Jacket most suitable in India?
How we position Fosroc Life Jacket
Fosroc Life Jacket is a specialist marine corrosion-protection system, not a general repair mortar, so it sits alongside rather than competing with Fosroc’s standard repair range. On the same project it is typically paired with Renderoc LJ (its dedicated conductive fill grout) and complements Fosroc’s discrete galvanic anodes such as Galvashield CC and the Galvashield XP/embedded anode family, which are used to protect patch repairs in atmospherically exposed concrete where a full jacket is not warranted. For owners weighing protection strategies, the main alternative is impressed-current cathodic protection (ICCP) — more powerful and adjustable, but requiring permanent power, rectifiers and maintenance — whereas Life Jacket offers a self-powered, low-maintenance route. Competing galvanic and CP technologies in the Indian market include Sika’s FerroGard and Sika galvanic anode systems, MBS/MC-Bauchemie corrosion-protection products, and surface corrosion-inhibitor and protective-coating options from STP and Dr. Fixit; STRUCTURAL TECHNOLOGIES’ LifeJacket is the closely related parent technology internationally. Space Arc Engineering positions Fosroc Life Jacket as the preferred choice where genuine, monitorable cathodic protection of marine piles is required and where a single-operation repair-plus-protection solution gives the best whole-life value.
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