Concrete densifiers are silicate sealers of a sodium, potassium or lithium carrier designed to densify, harden, dustproof and increase the abrasion resistance of concrete. Most commonly used on warehouse floors in conjunction with a floor machine to polish and add a shine.
Most Important Features When Purchasing a Concrete Densifier:
- Concentrated densifier so the water to sealer ratio can be controlled at a more cost effective price point
- Resistance to mold, mildew, efflorescence, abrasions and dusting
- Look for an industrial grade silicate with substantial penetration that is chemically reactive with a guaranteed warranty.
Most Popular Concrete Densifier Brand Reviews:
Concrete Sealer X-1: Silicate sealer that is permanent, penetrates 4 inches and leaves a natural looking concrete finish. Non-toxic, low VOCs with a 2 year shelf life applied by a brush or roller.
LiON Hard: Environmentally friendly lithium silicate sealer, VOC compliant and non-yellowing. Densifies and dustproofs all while creating a non-slip surface.
Prosoco LS: Chemically reactive lithium silicate, one coat application, abrasion resistant, slip resistant, non-yellowing and VOC compliant.
Concrete is extremely porous by nature filled with small capillary pores and voids that are extremely susceptible to damage from cracking, spalling, water, moisture, mold, efflorescence, and hydrostatic pressure to name a few. In order to prevent all of these disastrous situations there are a few methods of prevention. A concrete densifier is the most effective solution to help prevent concrete from degradation and deterioration. A densifier is usually silicate based in either a sodium, potassium or lithium carrier. Out of the three, the lithium seems to be the most effective since it is a newer technology with less risk of concrete whiting and hazing.
Concrete densifiers are penetrating formulas that seep into the concrete, reacting chemically to form additional calcium silicate hydrate thus strengthening and hardening a concrete slab. The slab is then protected from cracking and spalling. Some densifiers claim to waterproof but these are false claims unless the silicate densifier is combined with a waterproofing siliconate molecule. They are known as silicate siliconate blends that are excellent densifiers and waterproofers. Densifiers are also ideal for polishing, grinding and burnishing concrete. They are usually applied before and after polishing concrete adding extra protection and strength.
Polished concrete is one of the newer choices many people make for their concrete surfaces. Concrete naturally is a very porous material made from the mixing of water, Portland cement, and some sort of aggregate, such as stones, gravel, or sand. The mixture, when properly completed, results in the formation of concrete that features a large amount of tiny pores and hairline cracks that extend, web-like, throughout the concrete. While these pores and cracks do not overly inhibit the concrete’s strength, they can be the cause of future damage.
To make sure your concrete is as strong as it possibly can be, as well as protected from potential future harm, you need to make sure you seal your concrete with the appropriate concrete sealer. However, the situation changes slightly if you decide to polish your concrete. Polishing concrete is a choice many people make because it grinds down the surface of the concrete to transform the pockmarked natural surface into a smooth, shiny expanse of concrete. These types of floors are typically found in large retail stores, such as Home Depot, as well as a number of other venues.
While the polishing process is as simple as renting a concrete grinder and following the instructions from there on, there is a crucial step that many people skip. Skipping this step, of course, can result in absolute disaster for the concrete, leading to excessive cracking, crumbling, and general degradation that can necessitate costly repairs.
Before you can polish concrete, you need to increase the strength and density of the slab. Polishing pushes the concrete’s structural integrity to the brink, which can be problematic for untreated concrete. In order to ensure a successful concrete polishing process, you need to treat the concrete slab with a concrete densifier. The best choice for this project would be a lithium silicate/siliconate. These types of sealer are the strongest densifiers on the market, featuring deep penetration and comprehensive chemical reactions that create more calcium silicate hydrate (or CSH) that gives concrete its noted strength. Once the lithium silicate sealer has been properly applied, the concrete can be polished without fear of damage caused by untreated concrete.
What is a concrete densifier, and what is the best concrete densifier? According to the Internet, “A concrete densifier is a chemical applied to a concrete surface in order to fill pores, increasing surface density. Chemical densifiers are used on polished and non polished slabs to reduce dusting and wear; on polished concrete surface densifiers help concrete take a better polish and make the surface less permeable to liquids so the slab does not require sealing.”
Now lets explore this: Why would you need a concrete densifer in the first place? Concrete is composed of three ingredients, Portland cement, aggregate and water. It may seem simple but concocting the exact ratio of these three components is tougher than you think. If the proportions are even slightly off it will result in weakened concrete that will begin to deteriorate. After concrete is poured it solidifies and hardens through a chemical process called hydration. Water reacts with the cement and causes all of the ingredients to bond together. If too much water was added to the mix and the water-cement ratio is off, the aggregate will begin to separate from the cement paste. If water is not fully absorbed through hydration some of it may evaporate as it hardens resulting in bleeding that will reduce the final strength of concrete. A mix with too much water will also experience increased shrinkage and visible cracks which will also affect the strength of concrete. That being said when you buy a home that already has a poured concrete basement, driveway, patio etc. you do not know what the water-cement ratio was when poured. In most cases since the ratio is so difficult to perfect it is adequate to assume your concrete will weaken with time.
By applying a concrete densifier you are permanently closing the pores in the concrete thus in fact hardening the concrete and making it stronger. There are a few types of concrete densifiers on the market today. The oldest and most popular being silicate based densifiers. They can include sodium silicates, potassium silicates, lithium silicates or a combination. Silicate densifiers are chemically reactive sealers that penetrate and react with calcium silicate hydrate or C-S-H. C-S-H is the same material that is produced in the reaction between Portland cement and water giving concrete much of its original strength. When a densifier is applied to the surface of concrete the silicate begins to immediately react with the calcium hydroxide. Not only does densifying begin but the once empty pores of the concrete are filled creating a tougher, stronger concrete slab. But beware silicate sealers are known to leave a white residue called carbonation on the surface (When silicate left on the surface that did not penetrate reacts with carbon dioxide in the atmosphere.) This is often times difficult to remove. A newer technology on the market is a colloidal silica densifier. It is claimed that colloidal silicas are the silicates of the future since they have a low viscosity, penetrate deep and also react with lime found in concrete. Since colloidal silicas have the ability to bond to itself (silicate sealers cannot do this) it can densify stronger and has the ability to bond to cement products not made from regular Portland cement. It is claimed colloidal silica is safer to use than traditional silicates and since there are small amount of metallic salts compared to silicates, there will never be whiting left on the surface. Application is quicker (the slab is dry in 1-2 hours vs. 6-24 hours.) But which densifier is the best choice?
Our take : Best Concrete Densifiers
When it comes to silicate sealers we feel the best densifier and hardeners are lithium based. Since lithium silicates will react with calcium hydroxide present in concrete to produce the same molecule that concrete naturally forms to hold itself together (C-S-H) we feel this is the strongest, most durable densifier. They have a faster dry time than sodium silicate densifiers and they are a cost effective solution to harden concrete. We like the concentrated Lithi-Tek 4500.