Shake-On Hardeners

For more information, see the Product Selection Guide.

Suggestions for form shake-on hardeners include, but are not limited to, the following:

Symons highly recommends having the concrete mix design evaluated prior to installation. No calcium chloride admixture should be used in the concrete mix. Contact Technical Services for details.
The concrete slump should not exceed 5" (12.7 cm). The addition of too much water to the concrete mix will significantly lower the compressive strength and the durability of the concrete surface.
The base slab should not contain more than 3% entrained air for shake-on hardener application. Too much air entrainment can excessively slow down bleed water migration to the concrete surface and create finishing problems. It can also create blisters on the concrete surface due to the trapping of the air in the concrete slab.
The use of a vapor barrier underneath the concrete slab is not recommended for shake-on hardener applications. All of the moisture in the slab must then migrate out to the top surface, creating long delays for the application of the shake-on hardener. A vapor barrier can create a "curling" problem with differential drying of the base slab, unless the curing conditions are near perfect.
During application of the shake-on hardener, two applications of the material are recommended, typically, 2/3 of the material is applied during the first pass and the rest on the second pass. This helps ensure that no areas on the concrete surface are missed during the application.

The preferred method of applying a shake-on floor hardener is with a mechanical spreader. A Morrison, Somero, Allen or similar spreader is recommended for uniform application. If the material is applied by hand or shovel, do not throw the material too far or too high. This can result in a separation of fines and granular material in the shake-on material.
Always allow the shake-on hardener to remain on the surface and soak up water until it darkens and is uniform in color. Float the surface with wood floats or float blades to integrate shake-on hardener into the surface. Do not use a steel trowel because it will "seal" the concrete surface too soon, trapping excess air and moisture in the slab.
After all surface water has disappeared and the concrete is firm and ready for final finishing, use a steel trowel or steel blade for a smooth finish. Combination blades should not be used on shake-on hardener projects. For light reflective shake-on hardeners, always use stainless steel blades for finishing.
Curing is critical. Use a wet burlap cure or a Symons curing compound. We recommend Cure & Seal 309 WB or Cure & Seal 1315 as a cure and sealing compound if no subsequent coating is required. Do not use a water cure, wet burlap cure, or waterproof paper to cure a colored shake-on hardener surface.

Available in solvent or water-based formulations.

Enhance concrete performance or correct problems.

Resin-based systems correct structural concrete problems and protect concrete surfaces.

Polyurea-based systems to repair and protect concrete joints and nosings, even in low temperature conditions.