In the repair and rehabilitation of reinforced concrete structures, damaged sections often require a material that can be placed in restricted locations while maintaining strength, dimensional stability and durability. Conventional concrete placement can become difficult where access is limited or vibration is not practical.
Renderoc RG is a ready-to-use, non-shrink cementitious microconcrete designed for repairing damaged reinforced concrete elements and carrying out structural strengthening applications. It requires only the addition of clean water at site to produce a free-flowing repair microconcrete.
The material is based on Portland cement, graded aggregates, fillers and additives that provide controlled expansion in the plastic state while reducing water demand. It can be used for concrete repairs, encasement build-ups, jacketing of structural members and pile-top encapsulation.
Challenges in Concrete Repair and Structural Strengthening
Damaged reinforced concrete structures can present several repair challenges:
- Restricted access to damaged sections
- Difficulty in placing conventional concrete
- Areas where vibration is difficult or impossible
- Concrete deterioration around reinforcement
- Corrosion of embedded reinforcement
- Requirement for dimensional stability after placement
- Need for rapid reinstatement of repaired areas
- Repairs requiring pumping or pouring into formwork
Selecting an appropriate repair microconcrete helps achieve proper filling, strength development and long-term performance.
Renderoc RG Microconcrete
Renderoc RG is supplied as a pre-packed dry powder blend that requires the addition of clean water to produce a flowable, non-shrink repair microconcrete.
Its controlled expansion characteristics compensate for shrinkage and settlement during the plastic stage. The low water requirement supports early strength development and the durability of the hardened repair.
Key Applications
Renderoc RG is suitable for:
- Repair of damaged reinforced concrete elements
- Structural strengthening
- Column jacketing
- Beam jacketing
- Slab strengthening
- Pile encasement
- Pile-top encapsulation
- Encasement build-ups
- Repairs in restricted-access locations
For larger repair sections, appropriately graded coarse aggregate can be incorporated as recommended for the specific application.
Why Choose Renderoc RG?
Controlled Expansion
The gaseous expansion mechanism compensates for shrinkage and settlement while the material is in its plastic state.
Flowable Placement
The microconcrete has high flowability, allowing it to reach restricted locations without requiring vibration.
Pumping and Pouring
Renderoc RG can be pumped or poured depending on the repair configuration and access conditions.
Pre-Packed Material
The pre-packed formulation helps reduce variations associated with site batching of individual ingredients.
Early Strength Development
The material develops strength rapidly, helping facilitate earlier reinstatement of repaired areas.
Low Permeability
The cured repair provides high ultimate strength and low permeability, supporting long-term durability.
Chloride-Free Formulation
Renderoc RG contains no chloride admixtures, making it suitable for reinforced concrete repair applications where chloride introduction is to be avoided.
Typical Performance Properties
The reported typical properties of Renderoc RG include:
| Property | Typical Value |
| Compressive strength – 1 day | 10 N/mm² |
| Compressive strength – 3 days | 30 N/mm² |
| Compressive strength – 7 days | 40 N/mm² |
| Compressive strength – 28 days | 50 N/mm² |
| Tensile strength – 28 days | 2.0 N/mm² |
| Flexural strength – 28 days | 5.0 N/mm² |
| Young’s modulus | 25 kN/mm² |
| Unrestrained expansion | 1–4% |
| Thermal conductivity | 1.5 W/m°C |
| Fresh wet density | 2100–2200 kg/m³ |
| Fire rating | Class A1 |
Actual performance can vary depending on site conditions, mixing, placement, curing and the specific repair configuration.
Applications Across Structural Repairs
Column and Beam Jacketing
Renderoc RG can be used for jacketing applications where additional concrete is required around existing structural members. Its flowability helps fill formed sections around reinforcement.
Pile Repair and Encasing
The material can be used for pile-top encapsulation and encasement where damaged or deteriorated concrete requires reinstatement.
Restricted-Access Repairs
Where conventional concrete placement and vibration are difficult, the flowable nature of Renderoc RG allows material to be pumped or poured into the required location.
Structural Encasement
The microconcrete can be used for encasement build-ups as part of structural strengthening and rehabilitation work.
Application Guidelines
Surface Preparation
Before application, defective concrete should be removed until a sound substrate is reached. Smooth surfaces should be mechanically roughened.
Where reinforcement is exposed, corrosion products and loose scale should be removed around the reinforcement. The reinforcement should be cleaned to a bright condition, with grit blasting recommended where appropriate.
A suitable reinforcement primer such as Nitozinc Primer can then be applied as specified for the repair system.
The concrete substrate should be saturated with clean water several hours before placement. Immediately before application, all standing or free water should be removed.
Mixing
Renderoc RG should be mixed using suitable forced-action mixing equipment or an appropriately sized high-torque drill and mixing paddle.
The typical water requirement is approximately 3.75–4.0 litres per 25 kg bag. The water quantity should be accurately measured, and the specified maximum should not be exceeded.
After adding the powder gradually to the water, continuous mixing is required to obtain a smooth and uniform consistency.
Formwork
Formwork should be sufficiently rigid and slurry-tight to withstand the hydraulic pressure generated by the flowable microconcrete.
For gravity-fed placement, a suitable feed hopper should be provided at the highest point. Air vents may be required to minimise air entrapment.
Placing
The mixed material should be placed immediately after mixing.
For pumping applications, standard concrete pumping practices should be followed. When pouring into formwork, placement should generally proceed from one side to help reduce the possibility of trapped air.
Curing
Curing should begin immediately after formwork removal in accordance with good concrete practice.
Suitable curing compounds can be used to maintain moisture. In demanding drying conditions, additional measures such as wet hessian and polyethylene sheeting may be required.
Design and Application Parameters
Renderoc RG can generally be applied at depths of up to 100 mm in a single application. For deeper sections, appropriately graded aggregate may be incorporated depending on the repair configuration.
For sections exceeding the recommended application depth, the repair design and aggregate requirements should be evaluated for the particular project.
Packaging and Storage
Renderoc RG is supplied in 25 kg bags.
The reported yield is approximately 13 litres per 25 kg bag, although actual yield can vary according to consistency and the quantity of coarse aggregate incorporated.
For storage, the product should remain in its original, unopened packaging and be kept in a dry location. The stated shelf life is six months, subject to recommended storage conditions.
Built for Structural Repair Professionals
Contractors
- Flowable placement
- Pumping or pouring options
- Reduced site batching variations
- Faster reinstatement
Structural Engineers
- Suitable for structural strengthening applications
- Controlled expansion characteristics
- High ultimate strength
- Low permeability
Applicators
- Pre-packed material
- Simple water addition
- Suitable for restricted-access repairs
- No vibration required for many applications
Builders and Project Owners
- Suitable for rehabilitation of damaged concrete
- Supports durable repair applications
- Applicable to multiple structural elements
Typical Project Applications
Renderoc RG can be considered for repair and strengthening applications involving:
- Reinforced concrete columns
- Beams
- Slabs
- Piles
- Pile tops
- Structural encasements
- Concrete strengthening works
- Restricted-access concrete repairs
- Damaged reinforced concrete elements
- Concrete rehabilitation projects
Concrete rehabilitation requires materials that can fill repair sections effectively while providing strength, dimensional stability and durability after curing. Renderoc RG provides a flowable, non-shrink cementitious microconcrete solution for reinforced concrete repair, structural strengthening, jacketing, encasement and pile repair applications. Its controlled expansion, high flowability, early strength development and low permeability make it suitable for repair locations where conventional concrete placement may be difficult.
