About Fosroc Lokfix

Fosroc Lokfix is a polyester-resin anchoring grout system engineered for high-strength, corrosion-resistant fixing of bolts and reinforcement bars into structural substrates. Unlike cementitious grouts that rely on hydration and several days of curing, Lokfix is a two-component thermosetting polyester resin: a resin base and a catalysed filler that are mixed on site and chemically cure within hours, allowing load to be applied the same working day. It is supplied pre-measured so that the resin-to-filler ratio is fixed at the factory, removing one of the most common sources of on-site error and producing anchorages of consistent, reproducible capacity. The Lokfix family comes in three grades to suit the geometry and orientation of the anchor. Lokfix S (small aggregate) is the standard pourable grade used where the annular gap between hole and bar is less than 25 mm. Lokfix L (large aggregate) is used for wider gaps, where the hole diameter exceeds the bar by 25 to 50 mm. Lokfix P is a thixotropic, pumpable grade for overhead and horizontal holes – its non-sag rheology prevents the resin running back out of the hole before it gels. All three are used for the same fundamental task: anchoring bolts and bars from 12 mm to 51 mm diameter into concrete, rock, masonry or brickwork where high speed of installation and early loading are required. Typical Indian applications include holding-down bolts for plant and steelwork, reinforcement starter bars and dowels for new-to-old concrete connections, balustrade and crash-barrier posts, safety fences, railway track fixings, tie-back anchors and ground anchors for towers and cranes. Because the cured resin is chemically inert and watertight, Lokfix is well suited to marine, industrial and infrastructure environments where chloride attack would corrode a poorly protected steel anchor.

The technical insight

The performance of a Lokfix anchorage is governed by the bond developed along the resin-to-bar and resin-to-substrate interfaces, not by expansion or wedging as in a mechanical anchor – Lokfix is deliberately non-expansive, which means it can be installed close to a concrete edge without inducing splitting, a frequent failure mode with expansion bolts. Ultimate capacity depends on four factors that the designer controls: the strength of the host material, the embedded bond length, the quality of hole preparation, and the type and diameter of the bar. Fosroc’s data sheet gives a design formula derived from BS 8110 for the minimum embedment of Type 1 deformed rebar, using a characteristic steel yield of 460 N/mm2 and a permitted concrete shear stress that rises with concrete grade (1.8 N/mm2 at 20 N/mm2 concrete up to 2.5 N/mm2 above 40 N/mm2). The cured grout itself reaches an ultimate compressive strength of about 70 N/mm2 at seven days (50 mm cube, BS 6319 Part 2:1983), but in a correctly designed anchor the failure mode is the surrounding concrete, not the resin. A defining characteristic of polyester resin chemistry is its strong temperature dependence: gel time and minimum cure-before-loading both shorten dramatically as ambient temperature rises – 80 minutes gel and 7 hours to load at 20C, but only 15 minutes gel and 1 hour to load at 40C. This is why hole preparation matters so much: rough-sided, dust-free, dry holes formed by rotary-percussive drilling with air or water flushing give optimum mechanical key, while smooth diamond-drilled holes must be under-reamed to develop equivalent bond.

Where it is used

• Holding-down and foundation bolts for steel columns, machinery base plates and plant
• Reinforcement starter bars and dowel bars connecting new concrete to existing structures
• Balustrade, handrail, crash-barrier and safety-fence post fixings
• Railway track and sleeper anchor fixings
• Tie-back anchors and ground anchors for retaining walls, towers and cranes
• Anchoring bolts and bars into rock, masonry and brickwork on repair and strengthening works
• Dock sills, abutments and other marine or water-retaining fixings requiring corrosion resistance

Key advantages

• Rapid strength gain allows early application of load – often the same working day
• Pre-measured two-part packs eliminate site batching errors and give reproducible anchor capacity
• Non-expansive cure permits anchoring close to concrete edges without splitting the substrate
• Excellent corrosion resistance and watertightness – can even be placed under water
• Resistant to vibration, making it suitable for machinery, rail and dynamic-load fixings
• Chemically resistant to fresh and salt water, petrol, oils, grease and most acids, alkalis and solvents
• Three grades (S, P, L) cover vertical, horizontal, overhead and wide-gap anchor geometries

Limitations & considerations

• Polyester resin softens and creep becomes significant above about 40C operating temperature, so it should not be used where load-bearing performance must survive fire conditions
• Flammable in the liquid state (flash point ~29C) – confined areas must be well ventilated with no naked flames and no smoking during use
• Short pot life, especially in hot Indian conditions (gel time falls to ~15 minutes at 40C), so mixed material must be placed quickly
• Partial packs must not be mixed – the pre-measured ratio is lost, so unused capacity in a pack is wasted
• Requires rough-sided, dust-free, dry holes; smooth diamond-drilled holes need under-reaming and damp or oily bars reduce bond
• Limited shelf life of 6 months when stored below 25C in unopened containers
• Skin contact with the uncured resin may sensitise; gloves, barrier creams and eye protection are required

Selection & best practice

Specifications

Industry use cases

How we position Fosroc Lokfix

Within the Fosroc range, Lokfix is the fast, economical polyester-resin choice for general bolt and bar anchoring, sitting alongside the epoxy-based Lokfix EP and the Lokfix E-series (E35, E45T, E55, E77) and Lokfix S80/P80, which Fosroc positions for cracked-concrete, post-installed rebar and heavier-duty or higher-temperature anchoring. It complements the cementitious Conbextra grout family used for base-plate and large-void grouting and Nitobond bonding agents used for new-to-old concrete connections. Among competitors available in India, the closest alternatives are Sika AnchorFix and Sika polyester capsule anchors, Hilti’s HIT injection resin systems for engineered anchoring, MYK Laticrete / MBS and STP grout ranges, and value-segment options from Dr. Fixit. Lokfix’s strengths are its pre-measured packaging, proven track record on Indian infrastructure, rapid strength gain and corrosion resistance; where the design demands cracked-concrete approvals, seismic qualification or fire performance, an epoxy or capsule anchor (Fosroc Lokfix EP/E-series, Sika or Hilti) is the more appropriate specification. As an authorised Fosroc distributor and applicator across Delhi NCR and Pan-India, Space Arc Engineering can supply Lokfix in all grades and advise on the correct grade, embedment and safety factor for your anchor design.

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