When Concrete Needs Mortar Repair
Concrete structures deteriorate over time due to environmental exposure, chemical attack, impact damage, and corrosion of embedded reinforcement. When deterioration causes section loss — spalling, delamination, or honeycombing — the damaged concrete must be removed and replaced with a repair mortar that restores the original section geometry and structural capacity.
The repair mortar market offers dozens of products in three main categories: epoxy-based, polymer-modified cementitious, and high-performance cementitious. Choosing the right type depends on the repair depth, structural requirements, exposure conditions, and project constraints.
Our Repair Mortar Product Range
Epoxy Repair Mortar (XQ-SJ-E)
A two-component epoxy resin mortar with high strength and excellent chemical resistance.- Compressive strength: ≥ 70 MPa
- Flexural strength: ≥ 30 MPa
- Bond strength to concrete: ≥ 3.0 MPa
- Chemical resistance: Excellent (acids, alkalis, solvents)
- Maximum repair depth per layer: 30mm
- Best for: Chemical plant repairs, thin section repairs (5-30mm), situations requiring rapid strength gain
Polymer-Modified Repair Mortar (XQ-SJ-P)
A cementitious mortar enhanced with polymer additives for improved bond, flexibility, and durability.- Compressive strength: ≥ 45 MPa
- Bond strength: ≥ 2.5 MPa
- Shrinkage: Low (polymer modification reduces cracking)
- Maximum repair depth per layer: 50mm
- Best for: General structural repairs, corrosion-damaged concrete, patch repairs in moderate environments
Rapid-Set Repair Mortar (XQ-SJ-R)
A fast-hardening cementitious mortar for emergency repairs and time-critical projects.- Compressive strength at 1 hour: ≥ 20 MPa
- Final compressive strength: ≥ 55 MPa
- Initial set: 15-20 minutes
- Best for: Road and bridge deck emergency repairs, traffic-bearing surfaces, winter applications
Structural Repair Mortar (XQ-SJ-SR)
High-strength cementitious mortar designed for load-bearing structural repairs.- Compressive strength: ≥ 60 MPa
- Elastic modulus: Similar to parent concrete
- Maximum repair depth per layer: 75mm
- Best for: Column and beam repairs, structural section restoration, load-bearing elements
Self-Leveling Mortar (XQ-SJ-LV)
Fluid cementitious mortar that flows to fill irregular surfaces without vibration.- Compressive strength: ≥ 40 MPa
- Flow spread: ≥ 500mm
- Best for: Floor leveling, large area repairs, filling irregular cavities
Anti-Corrosion Polymer Mortar (XQ-SJ-AC)
Specialized mortar with corrosion inhibitors for repairing concrete damaged by reinforcement corrosion.- Compressive strength: ≥ 50 MPa
- Chloride ion diffusion coefficient: Very low
- Contains migrating corrosion inhibitors
- Best for: Marine structures, bridges in de-icing salt environments, coastal buildings
Selection Guide: Matching Mortar to Application
| Application | Recommended Product | Why |
|---|---|---|
| Chemical plant floor | Epoxy (XQ-SJ-E) | Chemical resistance |
| Bridge pier patch | Polymer-modified (XQ-SJ-P) | Bond + durability |
| Highway emergency repair | Rapid-set (XQ-SJ-R) | Opens to traffic in 2 hours |
| Column section restoration | Structural (XQ-SJ-SR) | Load-bearing capacity |
| Factory floor leveling | Self-leveling (XQ-SJ-LV) | No vibration needed |
| Coastal bridge repair | Anti-corrosion (XQ-SJ-AC) | Corrosion protection |
Application Best Practices
Regardless of which repair mortar you choose, these principles apply to all concrete repair:
1. Remove all deteriorated concrete: Cut back to sound concrete in all directions. The repair boundary should be squared off with saw-cut edges (no feathered edges, which will debond). 2. Prepare reinforcement: If rebar is exposed, clean to bright metal by sandblasting or wire brushing. Apply corrosion-inhibiting primer if the mortar does not contain inhibitors. 3. Saturate the substrate: Concrete substrate should be saturated surface-dry (SSD). Apply water 2-4 hours before repair. Remove standing water immediately before mortar application. 4. Apply bonding agent if required: Some mortar systems require a slurry bond coat applied to the prepared surface just before the mortar. Check the product datasheet. 5. Place and compact: Apply mortar in layers not exceeding the maximum thickness specified. Compact each layer to eliminate voids. 6. Cure properly: Moist cure for minimum 7 days using wet burlap, curing compound, or plastic sheeting. Inadequate curing is the most common cause of repair cracking.