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
Everything above this section matters less than this section. Bond fails at the weakest interface, and on failed repairs that interface is almost never the bonding agent. It is laitance, curing compound, oil, or dust that was under the slurry the whole time. With good prep, all four of these products hold. With bad prep, none of them do, and the more expensive one just fails more expensively.
What has to come off:
- Laitance, the weak surface paste. It is bonded to nothing and it will take your topping with it.
- Curing compounds and sealers. Invisible on a swept slab and completely bond-breaking. Assume a slab has one until you have proof otherwise.
- Oil, grease, and tire rubber. Degrease first, then profile. Profiling over oil just drives it deeper.
- Old adhesive, paint, and efflorescence.
- Unsound concrete. Sound the area with a hammer or a chain drag and chase the hollow until it rings solid. Bonding to delaminated concrete gets you a repair that fails with the substrate it was stuck to.
Profile mechanically. Shot blasting is the best answer on open flat areas: uniform, dry, and it contains its own dust. Diamond grinding handles edges, corners, and small work, but watch the segment choice, because too fine a grind polishes the surface closed. Scarifying and milling are for thicker overlays where a coarse profile is wanted. Match the profile to the topping thickness: thin and featheredge work needs a finer, uniform texture; thick toppings want a coarse one for mechanical interlock. Verify against ICRI profile chips rather than by eye.
Acid etching is the shortcut that causes the failures. It does not remove oil, it does not remove curing compound, it produces an inconsistent profile, and it leaves residue and salts behind unless the neutralize-and-rinse is done thoroughly. On interior work with no drainage it is also a mess to handle. If a repair has to hold, profile it mechanically.
Verify before the slurry goes down:
- Vacuum, then check with a wipe or a piece of tape. Any dust that comes up is dust that would have been under the bond.
- Sound the area again after profiling. Aggressive prep sometimes reveals delamination that was not evident before.
- Confirm the moisture condition the product actually wants: dry for the epoxy-modified slurries, saturated surface-dry with no standing water for the latex systems.
- On specified work, a pull-off test per ASTM C1583 on a mockup settles the question with a number. On residential work, a small test patch placed a week ahead of the real repair does the same job for the cost of an hour.
Prep and place the same day. A profiled slab left open overnight collects dust, foot traffic, and moisture. If it sits, re-vacuum and re-check moisture before anything gets brushed on.
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.