Water-based Penetrating Concrete Sealer

Concrete sealers come in many formulations. Topical sealers coat the surface of the concrete and have the ability to change its appearance and create friction. Penetrating sealers contain molecules that penetrate the pores of the concrete and chemically react with it. This reaction does not change the appearance of the concrete but makes it less permeable to water. Penetrating sealers are generally applied with a sprayer, roller, or brush after concrete has fully cured. Manufacturer specifications vary, but some specify waiting up to 28 days after pouring the concrete before applying the sealer. Water-based penetrating sealers can be based on several different types of silicon chemistry. In addition to repelling water, some products can be fluorinated so that they also repel oil. Such products were beyond the scope of this research. This Common Product describes a penetrating concrete sealer made from a mixture of silanes and siloxanes. Silanes are smaller than siloxanes, so they are able to penetrate deeper into the concrete, while siloxanes are less volatile than silanes. 

The silane and siloxane molecules chemically react with silanol groups in the concrete to form a crosslinked silicone network. This process generates VOCs like ethanol and methanol, which are known as cure volatiles. California Air Resources Board (CARB) guidance indicates that manufacturers should include cure volatiles in their calculations when determining VOC content. Because water-based penetrating concrete sealers are based on silicon chemistry they are inherently resistant to UV degradation and do not require the addition of UV stabilizers.

A historical version of this Common Product is available here: https://pharos.habitablefuture.org/common-products/2209745