Curing compound
Types of Concrete Curing Compounds
Concrete curing compounds come in three main chemistries: wax, resin and acrylic, each sold water-based or solvent-based. Wax films stay until removed, resin films break down in weeks under sun and traffic, and acrylics act as a cure and seal. Pick resin if anything bonds to the slab later.
Every curing compound does the same first job: it puts a film on fresh concrete so the water stays in long enough to hydrate the cement. The types differ in what happens to that film afterward, and that is what decides which one belongs on your slab.
What are the main types of concrete curing compound?
There are three film formers you will see on US data sheets: wax, resin and acrylic. Each comes in a water-based or solvent-based version, clear, dyed or white. The big split is whether the film breaks down on its own or stays until someone removes it.
| Type | Film | Breaks down on its own? | OK under flooring later? | Typical use |
|---|---|---|---|---|
| Wax based | Soft wax membrane | No, stays until removed | No | Paving, curbs, slabs that stay bare |
| Resin based (hydrocarbon resin) | Thin resin film | Yes, in weeks under sun and traffic | Usually, once gone or cleaned off | Slabs that get flooring, coatings or sealer |
| Acrylic (cure and seal) | Harder, glossier film | No, it is meant to last as a sealer | No, unless the coating maker approves it | Exposed slabs you want sealed in one step |
| Sodium silicate | Reacts with the concrete | Not a film | Check with the flooring maker | Not a curing compound under C309 |
The Dayton Superior Guide to Curing says wax membranes “do not dissipate and will be present until removed,” while resin cures begin to wear off in 30 to 60 days under weathering, UV and abrasion.
What is a wax based curing compound?
A wax based compound leaves a soft paraffin type film that stays on the slab until it wears off under traffic or gets removed. It is the classic DOT paving cure, often in white. W.R. Meadows’ 1600-WHITE is a water-based wax dispersion with white pigment, rated Type 2, Class A.
The same data sheet says not to use it on surfaces that will later be painted, tiled, hardened, sealed or treated in any way. That warning is typical for wax. If anything has to bond to the slab, wax is the wrong type.
What is a resin curing compound?
A resin compound, usually a hydrocarbon resin, forms a thin film that oxidizes and breaks down under UV light and traffic. That breakdown is why resin products are sold as dissipating. The CC-309-1WS data sheet says the membrane begins to break down after about four weeks of UV exposure.
Breakdown is slower indoors, in shade, and where the crew sprayed heavy. Before flooring, the slab still has to be checked and cleaned. The details are in dissipating curing compound.
What is an acrylic curing compound?
An acrylic compound is usually sold as a cure and seal. It cures the slab, then stays on as a sealer. W.R. Meadows lists solvent-based acrylic cure and seals alongside its wax and resin emulsions on its concrete curing products page.
Because the film is built to last, it is the type most likely to cause bond trouble later. Euclid Chemical’s curing and sealing guide warns that a cure and seal may prevent proper adhesion of coatings, coverings and toppings. The higher spec for these products, C1315, requires at least 25% solids.
Water-based or solvent-based: what is the difference?
The carrier changes how the product handles on the job, not whether it cures. Water-based products are nonflammable and have no strong solvent odor, so they are the normal pick indoors. Solvent-based products penetrate further and look glossier, but the odor during application and drying makes them a poor fit indoors.
| Water-based | Solvent-based | |
|---|---|---|
| Odor and fire risk | Low odor, nonflammable | Strong solvent odor, flammable |
| Indoors | Usual choice | Discouraged by the Euclid guide |
| Look | Less gloss | Glossier |
| Cool, damp weather | Can turn white and chalky | Not flagged for chalking |
| Storage | Keep from freezing | Check the data sheet |
Water-based does not always mean low emissions. The CC-309-1WS sheet lists 42 g/L, while Euclid’s water-based Kurez DR VOX lists 301 g/L. Check the number against your local VOC limits for curing compounds before you order.
W.R. Meadows also says not to apply its water-based resin below 40°F (4°C) concrete temperature and to keep it from freezing in storage.
How do the types map to ASTM C309?
ASTM C309 does not name wax or resin directly. It sorts compounds by color (Type 1 clear, Type 1-D clear with fugitive dye, Type 2 white) and by solids (Class A with no restriction, Class B all resin). Dayton’s guide notes Class A products are typically wax based.
So a data sheet that says “Class B” tells you it is a resin product. One that says only “Class A” is often a wax. Many resin products list both Class A and Class B, as CC-309-1WS does.
Which curing compound type fits your job?
Start from what happens to the slab next. Bare slabs can take any type; anything that bonds to the concrete narrows it to resin.
- Paving, curbs, bare exterior slabs: wax or resin, white in hot sun
- Slab getting tile, vinyl, wood or carpet: wet cure if you can; otherwise a dissipating resin the flooring maker accepts, cleaned off before install
- Slab getting epoxy, urethane, a hardener or silane: resin, then clean it off; Dayton says compounds must be removed before these go down
- Exposed slab you want sealed in one pass: acrylic cure and seal
- Interior slab with crews working nearby: water-based
Read curing compound and flooring before you buy for any slab that will be covered. If you want a short answer for your own job, run the curing compound chooser.
If you already sprayed wax where flooring is going
A wax film will not go away on its own, so plan to take it off before the flooring crew arrives. Find out exactly what was sprayed: get the product name and data sheet, and check for Class A only or the word wax.
Frequently asked questions
What is concrete curing compound made of?
Most are a film former carried in water or a solvent. The film former is usually a wax, a hydrocarbon resin or an acrylic. White products add a white pigment to reflect sun. The carrier evaporates and leaves a thin membrane that slows water loss.
Is wax or resin curing compound better?
Neither is better everywhere. Wax is a good fit for paving and slabs that stay bare, because it stays put. Resin is the safer pick on any slab that will get flooring, coatings, sealer or a hardener, because the film breaks down and is easier to remove.
Should I use water-based or solvent-based curing compound?
Use water-based indoors and anywhere odor or flammability is a problem. Solvent-based products penetrate more and look glossier, but they smell during application and drying. Water-based products must not freeze.
Can you use concrete curing compound indoors?
Yes. Water-based products are the usual choice indoors because they are nonflammable and have no strong solvent odor, according to Euclid Chemical. Indoors there is little sunlight, so even a dissipating resin may not break down on its own before flooring goes in.
Is sodium silicate a curing compound?
Not under ASTM C309. Dayton Superior's guide says the ASTM committee on curing does not consider sodium silicate products to meet the spec, because silicates react with the concrete rather than forming a membrane.