Sika vs Mapei Concrete Bonding Agent Decision
Why this matters
Concrete-to-concrete bonding agents are how a thin topping or patch stays married to the substrate after the first thermal cycle. Sika Armatec 110 EpoCem, Sika Latex R, Mapei Planibond AE, and Mapei Planicrete UA are the four products a residential concrete crew is realistically choosing between at the supply house. They are not all the same product. Some are epoxy-modified cementitious slurries, some are acrylic-latex bonding admixtures, and the application method differs. Picking the wrong category costs a repair that delaminates inside a year. This article frames the decision crews actually make.
Three product categories that matter
Concrete bonding agents at residential-contractor scale fall into three categories. Picking the right category is the first decision; brand within category is a secondary call.
Acrylic-latex bonding admixtures. Used as either a bond slurry brushed onto the substrate (mixed with cement) or as gauge water in the topping mix itself. Sika Latex R and Mapei Planicrete UA are in this category. They are water-based, easy to clean, low-VOC, but limited in service-temperature and chemical-exposure tolerance.
Epoxy-modified cementitious bonding slurries. Sika Armatec 110 EpoCem and Mapei Planibond AE are in this category. Two- or three-component products mixed at the jobsite, brushed onto the substrate as a slurry, with a working window of 30-90 minutes after which the topping must be placed wet-on-wet onto the still-tacky slurry. Higher bond strength, better chemical resistance.
Pure epoxy bonding agents (not covered here). 100 percent solids epoxy resins brushed onto the substrate. Highest bond strength but require the topping to be placed within a tight working window and are unforgiving of substrate moisture. Specialty repair work.
Decision: substrate condition
The first cut is what the substrate looks like.
Sound, dry, surface-roughened concrete (CSP 3-5 per ICRI 310.2R, mechanically shotblasted or scarified) with no contamination: any of the four products will perform. The decision is cost and crew familiarity.
Slightly damp, sound substrate: acrylic latex bonding admixtures (Sika Latex R, Planicrete UA) tolerate damp substrates better than epoxy-modified slurries. Epoxy systems require SSD (saturated surface-dry) at best and prefer dry; placing Armatec 110 on a visibly wet substrate compromises the bond.
Substrate with embedded steel and risk of corrosion: Sika Armatec 110 EpoCem is the published product for this use case. It carries enough cement to passivate exposed steel and is the standard for concrete repair work over rusted rebar per ICRI guidance.
Substrate that will see chemical exposure (parking deck with road salts, equipment pad with oil, exterior driveway in F3 freeze-thaw with de-icing): epoxy-modified slurries outperform acrylic latex. Planibond AE and Armatec 110 are both rated for this exposure.
Decision: topping thickness
Topping thickness drives the choice almost as much as substrate condition.
Featheredge to 1/2 inch: bonding agent is the limiting factor. Use an epoxy-modified slurry. Armatec 110 EpoCem and Planibond AE both perform at featheredge.
1/2 inch to 2 inches: both categories work. Acrylic latex bonding admixture mixed into a cement-sand topping (1:3 cement-sand, 2 percent latex by weight of cement) is the cheaper option. Epoxy-modified slurry is the more durable option.
Above 2 inches: bonding agent is less critical because the topping has enough mass to resist differential thermal movement. Substrate prep and mechanical interlock (CSP 5-9) carry most of the load. Either category works; cheaper acrylic latex is acceptable.
Decision: working window
Acrylic latex bonding slurry (cement + Latex R or Planicrete + water brushed on the substrate) must be placed wet-on-wet. If the slurry dries before the topping arrives, the bond is broken; the crew has to re-roughen and re-slurry. In hot weather (above 85 F) or windy conditions, the working window is 10-20 minutes; in mild conditions, 30-45 minutes.
Epoxy-modified cementitious slurries (Armatec 110, Planibond AE) have a longer published open time, typically 60-120 minutes. The topping is still placed wet-on-wet but the working window is wider. For larger pours or crews with limited mixing throughput, the wider window is the deciding factor.
Decision: product-specific notes
Sika Latex R is published for use as both a bond slurry and as gauge water for the topping mix. The dual-use is convenient for small repairs. Latex R contains carboxylated SBR latex and is paint-grade workability when added to standard portland-sand-aggregate mixes. Published bond strength per ASTM C1583 pull-off is typically above 200 psi (substrate-cohesive failure) on properly prepared substrates.
Sika Armatec 110 EpoCem is three-component (Comp A liquid, Comp B liquid, Comp C cementitious powder). Mixed in sequence per the published TDS. Open time 90 minutes at 70 F. Published bond strength on prepared substrates exceeds 250 psi pull-off (substrate-cohesive failure). Carries enough cement and corrosion inhibitor to passivate exposed reinforcing steel.
Mapei Planicrete UA is the acrylic-latex equivalent. Used as bond slurry or gauge water. Published bond strength comparable to Latex R. Lower price point per gallon at most suppliers.
Mapei Planibond AE is the epoxy-modified equivalent of Armatec 110. Three-component, comparable open time, comparable bond strength. Lower published cement content means it is not the preferred product for corrosion-inhibited repair over exposed rebar (Armatec 110 is the spec on that work).
Decision matrix
| Substrate | Topping | Use |
|---|---|---|
| Dry, sound, no steel exposed | Above 1/2 inch | Sika Latex R or Mapei Planicrete UA |
| Damp, sound | Above 1/2 inch | Sika Latex R or Mapei Planicrete UA |
| Sound, exposed corroded steel | Any | Sika Armatec 110 EpoCem |
| Sound, chemical exposure | Above 1/4 inch | Sika Armatec 110 or Mapei Planibond AE |
| Sound, featheredge | Below 1/2 inch | Sika Armatec 110 or Mapei Planibond AE |
| Sound, large area, mild interior | Above 2 inches | Mechanical interlock plus any bonding agent |
Surface preparation is the actual variable
References
- Sika Armatec 110 EpoCem Product Data Sheet, current revision, usa.sika.com.
- Sika Latex R Product Data Sheet, current revision, usa.sika.com.
- Mapei Planibond AE Technical Data Sheet, current revision, mapei.com.
- Mapei Planicrete UA Technical Data Sheet, current revision, mapei.com.
- ICRI Guideline 310.2R, Selecting and Specifying Concrete Surface Preparation for Sealers, Coatings, Polymer Overlays, and Concrete Repair.
- ASTM C1583/C1583M, Standard Test Method for Tensile Strength of Concrete Surfaces and the Bond Strength or Tensile Strength of Concrete Repair and Overlay Materials.