Left to right: concrete pavers, clay pavers, natural limestone.
Paving Types and Recommended De-Icers
Not all types of paving material are equal when it comes to de-icers. The more porous the material, the more likely it will be damaged by a de-icer. High strength (PSI) and low porous material are other important factors that should be considered when applying de-icers. Holding up better doesn’t mean pavers are indestructible, so care should be taken to prevent overapplication. The following lists PSI of various materials and de-icer recommendations from manufacturers and a natural stone industry organization.
Clay pavers naturally have high PSI. Manufacturer Pine Hall Brick makes clay pavers with 12,000 psi average compressive strength. They recommend magnesium chloride as a de-icer for clay pavers, but advise not to use it on concrete.
Natural limestone and bluestone, with an average PSI of 5,000-7,000, are soft stones and are susceptible to damage from overuse of de-icers. The Natural Stone Institute recommends calcium chloride (CaCl2). It’s fast-acting, readily available, and works at very low temperatures– nearly eliminating the possibility of refreezing.
Concrete pavers have varying PSI depending on type, though some have been engineered with very high PSI and are able to hold up better to de-icers. For example, Unilock’s Brussels Block concrete pavers have a PSI of 8,000-12,500. They recommend rock salt (sodium chloride).
Poured concrete, has a lower average PSI of 2,500-5,000, and is very susceptible to de-icer damage during the first two years after it is installed. During this time you should not apply any de-icers; instead we recommend shoveling the snow/ice and spreading kitty litter or sand for traction.
Asphalt is not measured in PSI, but the Illinois Asphalt Pavement Association states that hot mix asphalt driveways are not impacted by certain chlorides contained in most de-icing agents, including sodium chloride, magnesium chloride or calcium chloride.
Additional Links for More Information:
Interlocking Concrete Pavers Institute: The Effects of De-Icing Chemicals on Interlocking Concrete Pavers
Unilock Paving: Winter Maintenance and De-Icing
Consumer Reports: How to Use Ice Melt