Repair Systems — 02 — Concrete & Structural Defects
Rebar primers and corrosion inhibitors
Technical product reference for zinc-rich cementitious rebar primers, two-component epoxy zinc-rich primers, and migrating corrosion inhibitors (MCI) applied to cleaned reinforcement after needle scaling in concrete spalling repair. Covers primer type selection by environment, minimum substrate cleanliness, and compatibility with repair mortar systems.
Rebar primers and corrosion inhibitors in concrete spalling repair
After cleaning corroded reinforcement to minimum St 2 (ISO 8501-1), a rebar primer or corrosion inhibitor is applied to the cleaned steel before placing repair mortar. This step is one of the most critical in the repair sequence — without a primer, freshly cleaned steel will begin to re-corrode within hours in humid or coastal conditions, and the repair mortar alone will not provide sufficient long-term protection against the corrosion mechanism that caused the original spalling. Selecting the correct primer type depends on the environment, the corrosion mechanism, and the repair mortar system.
Product Reference
Individual products — one card each — scroll to view all
Ardex Australia
Ardex BR 10 ZP
Single-part zinc-rich rebar primer — galvanic protection
Ardex BR 10 ZP is a single-part, zinc-rich primer for reinforcing steel that protects galvanically (sacrificial zinc). Apply a continuous film; a second coat may follow once the first is dry (~1 h @20 °C), and the repair mortar / micro-concrete is placed once the primer is dry to touch. CONFIRM dry film thickness, EN 1504-7 status and pack size against the current Ardex Australia TDS.
Fosroc / Parchem
Fosroc Nitoprime Zincrich
Zinc-rich epoxy rebar primer — 50 µm dry film
Fosroc Nitoprime Zincrich is a zinc-rich epoxy-resin primer that protects steel galvanically and as a barrier, applied in one coat at 50 µm dry (120 µm wet) and allowed to dry fully before the repair mortar. CONFIRM EN 1504-7 status, pack size and occupied-space VOC suitability against the current Fosroc / Parchem TDS.
Sika Australia
Sika MonoTop-910 N
Cementitious bonding primer + rebar corrosion protection (EN 1504-7)
Sika MonoTop-910 N is a one-component, polymer-modified cementitious coating with silica fume, used as both a bonding primer and reinforcement corrosion protection, conforming to EN 1504-7. Apply ~2.0 kg of powder per m² per 1 mm layer over at least two layers; the repair mortar is placed while the primer is still wet (wet-on-wet). CONFIRM pack size against the current Sika Australia TDS.
Mapei Australia
Mapei Mapefer 1K
Anti-corrosion cementitious rebar primer with corrosion inhibitor
Mapei Mapefer 1K is a one-component cementitious coating based on polymers in water dispersion, cement and corrosion inhibitors, brushed onto rust-free reinforcement to prevent corrosion. Apply two coats (~2 mm total; ~100 g/m on an 8 mm bar); the second coat 90–120 minutes after the first (preferably within 24 h). CONFIRM EN 1504-7 wording against the current Mapei Australia TDS.
System Comparison
Rebar primers & inhibitors — confirm all selections against the current manufacturer TDS before specifying.
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Do not confuse rebar primers and corrosion inhibitors with:
- Bonding agents and SBR latex primers — bonding agents are applied to the concrete substrate to improve mortar adhesion — rebar primers are applied to cleaned steel reinforcement — these are different products applied to different substrates — never apply a bonding agent to rebar or a rebar primer to concrete bond faces
- Surface-applied migrating corrosion inhibitors (applied to hardened concrete surface) — surface-applied MCI treatments such as Sika Ferrogard-903 applied to the outside of existing concrete are a different application from the rebar primer use described on this page — surface-applied MCI is used without chipping and repair to slow active corrosion in adjacent concrete
- Cathodic protection systems (impressed current or sacrificial anode) — galvanic anode systems and impressed current cathodic protection are engineered long-term corrosion management systems, not a substitute for rebar primer in a patch repair — if cathodic protection is specified by the engineer, a separate specialist system is required
- Galvanising — hot-dip galvanising of rebar provides zinc coating before concrete placement and is different from site-applied zinc-rich primers — not interchangeable in a repair application
- Epoxy coating for new rebar — factory-applied epoxy-coated rebar (green bar) is a product for new construction, not a repair primer — do not use epoxy-coated replacement bars in repair without engineering confirmation of bond adequacy in the repair mortar system
Disclaimer
This page provides general technical information only. Final product selection must be confirmed against the current manufacturer technical data sheet, project specification, substrate condition, exposure classification, AS 3600 requirements, and applicator warranty conditions. Do not rely on this reference as a substitute for professional engineering or remedial building consultant advice.