Chlorides don't care what they land on. Here's what actually harms concrete and landscaping, and what you can do about it.
Concrete: mostly a freeze-thaw problem
Sodium chloride doesn't chemically attack sound, properly air-entrained concrete in any big way. The main damage is freeze-thaw scaling: deicers keep the surface wet and raise the number of freeze-thaw cycles the top layer goes through, and pressure in the pores flakes off the surface.1
- New concrete (under about a year old) is the most vulnerable. Industry guidance (PCA/ACI) is to avoid deicers on concrete during its first winter, or at least its first year, and to use sand for traction instead.1
- Air entrainment and good finishing matter more than the deicer. Over-finished or non-air-entrained flatwork scales no matter what you put on it.1
- Never use ammonium-based deicers (ammonium nitrate, ammonium sulfate) on concrete. They attack the cement paste directly.1
- Magnesium and calcium chloride at high concentration can react chemically with cement paste over time. Follow label rates and don't pile them up.1
- A penetrating sealer (silane or siloxane) on walks and entrances reduces water and chloride uptake.1
Plants and turf
Chloride and sodium build up in soil along walks and lot edges. Sodium breaks down soil structure, and chloride is taken up by roots and burns foliage. Spray from traffic also damages evergreens along roads.
- Keep material on the pavement: narrow spinner patterns, deflectors, no throwing into beds.
- Use less: pre-wet, treat, calibrate. Every pound you don't spread is a pound that doesn't end up in the soil.
- Don't pile salty snow on beds and tree lawns.
- Flush beds with water in spring once the ground thaws, to move salt below the root zone.
- Burlap screens protect evergreens along busy drives.
- Choose salt-tolerant plants for curb strips and island beds.
Metal and vehicles: all chlorides are corrosive. Wash spreaders and trucks after events, grease what needs it, and check brine-system pumps and fittings for compatibility.
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