Penetrating sealers, such as silanes, siloxanes, silicates and siliconates, penetrate into the concrete to form a chemical barrier that shields against moisture penetration and deicing chemicals. Usually they provide invisible protection without changing the surface appearance, and most products are breathable, allowing moisture vapor to escape. They are most commonly used outdoors, since they provide excellent protection against harsh exposure conditions.
A penetrating sealer is your best choice if your goal is to:
Protect exterior concrete surfaces subject to corrosion and freeze-thaw damage.
Obtain a natural, matte finish.
Provide invisible protection without changing the surface appearance or leaving a sheen.
For driveways and walkways where good traction is important, a penetrating sealer is a better choice than a film-forming product, such as an acrylic or polyurethane. Because a penetrating sealer does not leave a glossy film, it will not contribute to the slipperiness of the concrete surface.