• Concrete is not susceptible to the erosive effects of salt. However, the steel bars that workers use to reinforce concrete--known as rebar--are susceptible to salt erosion. According to Today's Concrete Technology, regular concrete is already "one of the best protective coatings" for rebar. However, by mixing certain substances into the concrete before it cures, you can create a coating that is even more resistant to salt erosion.
  
  

Concrete with Blended Cement

• One concrete coating option for preventing salt erosion is to use concrete that contains blended cement. As the U.S. Department of Transportation notes, the American Society for Testing and Materials, or ASTM, defines blended cement as either a mixture of common Portland cement and blast furnace slag; or a mixture of Portland cement and pozzolan. While blast furnace slag is the non-metallic byproduct that results from smelting ore, pozzolan consists of volcanic ash particles. Blended cement helps decrease the porosity of the resulting concrete, which in turn helps prevent salt molecules from reaching the underlying rebar.
  
  

Concrete with Calcium Nitrite

• Calcium nitrite is a calcium-based compound that suppliers commonly mix in to concrete so that it represents about two percent of the total mixture, according to Today's Concrete Technology. In addition to inhibiting the corrosive effects of salt, calcium nitrite helps increase the strength of concrete coatings and accelerates the curing process. Unlike blended cement, which provides protection from salt by decreasing cement permeability, calcium nitrite forms a layer on top of the rebar within the concrete. This prevents chloride ions--the harmful aspects of salt molecules--from attacking. In addition, calcium nitrite helps prevent iron molecules that have been eroded from moving away from the rebar that they came from.
  
  

Concrete with Water-Reducing Agents

• Water-reducing agents in concrete have a similar function as blended cement: they help decrease concrete permeability, preventing salt molecules from reaching rebar. These agents allow you to mix concrete and maintain the necessary levels of flow while using a lower ratio of water-to-cement. The less water you use, the less permeable the resulting concrete will be. As Shandong Taihe Water Treatment notes, one of the best water-reducing agents for concrete coatings is polycarboxylic acid.
  
  

Surface-Treated Concrete

• In addition to mixing substances into concrete batches to improve the erosion-resistance of concrete coatings, you can also apply protective substances to the cured surfaces of concrete. Examples of these substances include epoxy resins, urethanes, coal-tar pitch, bituminous paints and rubber. However, as Today's Concrete Technology mentions, for these surface treatments to be effective, you must apply them to concrete before the concrete is exposed to salt and becomes contaminated.