Fosroc Renderoc RG SPL
A pourable, non-shrink cementitious micro-concrete that flows into congested reinforcement and deep repair pockets without vibration — reaching 30 N/mm² in a single day.
What is it?
A single-component, pre-bagged cementitious micro-concrete based on Portland cement, graded aggregates and a gaseous expansion system — mixed with only clean water on site to give a free-flowing, non-shrink repair concrete.
Where is it used?
Structural concrete repairs where access is tight and vibration is impractical — column and beam jacketing, encasements, pile-top encapsulation, and section rebuilds up to 100 mm deep.
Why use it?
It self-levels into heavily reinforced or awkward pockets, compensates for plastic shrinkage and settlement, and gains 30 N/mm² in 24 hours for early reinstatement.
How is it applied?
Machine-mixed with 3.50–3.75 L water per 25 kg bag, then poured or pumped into slurry-tight formwork from one side to avoid air entrapment; deeper pours take added coarse aggregate.
About Fosroc Renderoc RG SPL
Renderoc RG SPL sits in Fosroc’s Renderoc concrete-repair family as the flowable, placement-by-gravity-or-pump option. Where a hand-applied mortar such as Renderoc GP or Renderoc HB would be trowelled onto a vertical face, RG SPL is designed for the situations trowels cannot reach — repairs boxed in by dense reinforcement, deep pockets in beams and columns, jacketing build-ups, and pile-top encapsulation. It arrives as a ready blend of dry powders, so the only site variable is the clean water added, which removes the batching inconsistency that dogs site-mixed concrete. The formulation is built on Portland cement, graded aggregates and fillers, with additives that generate a controlled gaseous expansion in the plastic state to counter the shrinkage and settlement that normally leave a void at the top of a poured repair.
For Delhi NCR and pan-India contractors, the appeal is practical: a self-compacting repair concrete that fills the form on its own, hardens fast enough to strip and reinstate early, and behaves like the parent structure once cured. Because it carries no chloride admixture and no metallic aggregate, it suits repairs where long-term durability and reinforcement protection matter — bridges, industrial frames, water-retaining structures and marine substructure. A matched coefficient of thermal expansion means the repair moves with the host concrete rather than debonding at the interface over seasonal cycles. Space Arc supplies RG SPL alongside the primers, curing compounds and mould-release agents that complete the system, so a specifier gets the whole repair chain from one source.
The technical insight
The engineering problem RG SPL solves is the void that forms at the top of any conventional poured repair. Fresh cement paste bleeds and settles as it stiffens, and in a formed pocket that settlement pulls the repair away from the soffit or the underside of the reinstated section — exactly where good contact is most needed. RG SPL answers this with a gaseous expansion system that produces a controlled unrestrained expansion of 1 to 4% in the plastic state, gently pushing the material back up against the form and the surrounding concrete while it is still workable, then locking in that contact as it sets. Paired with a deliberately low water demand (a water:powder ratio around 0.15), this gives the cured repair its high early strength and low permeability. The low water content is what lets it reach 30 N/mm² at one day and 75 N/mm² at 28 days without sacrificing the fluidity needed to place it without vibration. Because the additive package minimises water while a superplasticised blend keeps the mix free-flowing, the applicator is not forced to choose between workability and strength — the two usually trade off, and here they don’t.
Where it is used
- Repairs to reinforced concrete where dense rebar blocks access for hand-placing or vibration
- Column and beam jacketing and structural encasement build-ups
- Pile-top encapsulation as part of a waterproofing system
- Deep pocket and section reinstatement up to 100 mm neat, or deeper with added aggregate
- Restoration of bridge piers, abutments and load-bearing frame elements
- Machine-base and plinth reconstruction where a flowable repair concrete is specified
- Industrial and infrastructure repairs needing early reinstatement and low permeability
- Congested-reinforcement patch pours where self-compaction is essential
Key advantages
- Free-flowing consistency places into restricted, heavily reinforced locations without vibration
- Gaseous expansion system compensates for plastic shrinkage and settlement, keeping full contact with the substrate
- Rapid strength gain — 30 N/mm² at 1 day — allows early formwork stripping and reinstatement
- High ultimate strength (75 N/mm² at 28 days) with low permeability for durable repairs
- Pre-bagged blend eliminates site-batching variation; only clean water is added
- Contains no chloride admixture and no metallic aggregate, protecting embedded steel
- Coefficient of thermal expansion matched to host concrete, reducing interface debonding
- Can be extended with 5–12 mm graded aggregate for larger and deeper pours
Limitations & considerations
- Requires slurry-tight, hydraulic-pressure-rated formwork with feed hoppers and air vents — not a trowel-on mortar
- Neat pours are limited to about 100 mm depth; deeper sections need added coarse aggregate to control heat rise
- Water dose is critical and must not exceed 3.75 L per 25 kg bag, or strength and expansion behaviour suffer
- Needs a forced-action mixer or high-torque paddle drill; hand mixing will not give a consistent flowable mix
- Exposed reinforcement must be cleaned to bright metal and primed with Nitozinc Primer before placing
- Six-month shelf life in unopened bags, shortened by high temperature or humidity in store
Selection & best practice
Cut back defective concrete to a sound base, mechanically roughen smooth surfaces, and expose corroded steel around its full circumference, cleaning it to bright metal by grit-blasting before applying one continuous coat of Nitozinc Primer. Saturate the substrate for several hours prior to placing and remove standing water immediately before the pour. Machine-mix each 25 kg bag with 3.50–3.75 L of clean water (never more than 3.75 L) for five minutes to a smooth, even consistency; where coarse aggregate is specified, add it after the base mix and blend one minute more. Pour or pump immediately into pre-wetted, Reebol-coated formwork, feeding from one side only and priming the pump line with cement slurry to avoid air entrapment. In cold weather down to 15°C use warm water up to 30°C; above 35°C store in shade and mix with cold water. Cure immediately after striking the formwork using Nitobond AR or a Fosroc Concure curing compound, supplemented by wet hessian or polythene in harsh drying conditions.
Specifications
| Product type | Single-component, non-shrink cementitious flowable micro-concrete |
| Compressive strength | 30 N/mm² (1 day), 60 N/mm² (7 days), 75 N/mm² (28 days) at w:p 0.15, 30°C |
| Flexural strength | 8 N/mm² at 28 days |
| Tensile strength | 2 N/mm² at 28 days |
| Young’s modulus | 25 kN/mm² |
| Unrestrained expansion | 1 to 4% (plastic state) |
| Mixing water | 3.50–3.75 L per 25 kg bag (max 3.75 L) |
| Max section depth (neat) | Up to 100 mm; deeper with 5–12 mm graded aggregate |
| Pack size / yield | 25 kg bag; approx. 12.0 litres per bag |
Industry use cases
Bridges & Highways
Reinstating deep pockets in piers, abutments and crossheads where reinforcement congestion rules out hand-placing and vibration.
Industrial Plants
Rebuilding machine bases, plinths and encased columns with a flowable repair concrete that reaches working strength within a day.
Marine & Water Structures
Pile-top encapsulation and substructure repair using a chloride-free, low-permeability micro-concrete that protects embedded steel.
Commercial & High-Rise Frames
Column and beam jacketing build-ups where self-compacting placement into tight formwork keeps the structure in service sooner.
Retrofit & Strengthening
Section enlargement and encasement for load upgrades, giving a repair that shares the host concrete’s thermal movement.
Frequently asked questions
Is Renderoc RG SPL a spray-applied mortar?
How deep a repair can I do in one pour?
How much water do I add per bag?
How soon does it gain strength?
Do I need to prime the reinforcement first?
What pack size does it come in and what is the yield?
How we position Fosroc Renderoc RG SPL
Within the Fosroc Renderoc range, RG SPL is the flowable, formwork-placed member — choose it when reinforcement congestion or geometry rules out trowelling; for hand-applied vertical and overhead patch repairs, specify Renderoc GP or Renderoc HB, and where the fastest possible reinstatement drives the job, Renderoc RG offers rapid high-early-strength gain. Pair RG SPL with Nitozinc Primer on exposed steel, Reebol mould-release on the formwork, and a Concure curing compound or Nitobond AR to complete the repair system. For precision grouting of base plates and anchor bolts — a related but distinct task — the free-flow Fosroc Conbextra GP2 is the correct product rather than a repair micro-concrete. Space Arc also supplies equivalent flowable repair and micro-concrete solutions from Sika, Dr. Fixit and MC-Bauchemie where a project standard or approved-vendor list calls for an alternative brand.
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