Asphalt and concrete sealants are used for patching and filling cracks and breaks, repairing and resurfacing concrete, grouting, leveling, and adding safety features such as anti-skid surfacing. These sealants typically have an epoxy or polyurethane base and are available as single or multi-part compounds. Sealants are designed to be self-leveling and have a thin consistency so they flow to low spots. Non-leveling products are thicker and designed to remain in place. Asphalt and concrete sealants are resistant to most liquids and chemicals.