Does Water Softener Salt Damage Your Concrete?
Unlike what people might have told you, water softener salt, or any salt for that matter, does not directly impact the integrity of your concrete.
So if your brine tank ruptured overnight, or your backwash drain has been leaking for a while, let me set your mind at ease and say your concrete will suffer no direct damage. However, in colder environments, cold snaps combined with salt could cause lower quality concrete to suffer damage over time.
What Effect Does Salt Have On Concrete?
Most water softener salt is nothing more than ordinary table salt, or NaClNatrium Chloride or Sodium Chloride. It is therefore no more harmful than spilling some salt on the floor or a deicing compound. Certainly, in warmer climates, there is nothing to be worried about.
However, if you are planning on using water softener salt as a deicing agent, there are some things to take into account.
So, Will Water Softener Salt Damage Concrete?
Research has shown that even after prolonged exposure to NaCl there is no direct effect on the deterioration of concrete. Water softener salt thus forms no direct threat to the condition of your concrete.
There is a reason why all docks are paved in concrete, the pontoons of deep-sea oil rigs are made from concrete, and why we use rock salt all over our infrastructure to avoid automobile accidents during the winter. It works!
Why Chemical Erosion Is Not An Issue
Although some research does show that Ca2+ and Mg2+ can cause harm to your concrete, the calcium and magnesium concentrations in backwash are simply not high enough to cause any damage.
Why And How Does Salt Damage Concrete
When salt and concrete are combined in colder climates there can be secondary effects that could prove detrimental to the condition of your concrete.
There are two mains ways in which salt can cause damage to concrete both of which are dependent on the initial condition of your concrete.
Concrete Degradation Due To Rebar Corrosion
If there are already cracks within your concrete this could make it possible for melting snow and ice to seep into your concrete and reach the inner rebar.
Rebars' main component is iron, which oxidizes as it comes into contact with water. This process is sped up when that water contains salt.
As the rebar in concrete starts to rust it will expand causing the concrete to crack further. This in turn opens up more access to the rebar resulting in more rust and accelerating the process.
Concrete Deterioration Due To Spalling
Even without rebar, the porous characteristics of concrete can be its downfall in colder climates when using salt as a deicing agent.
The damage occurs through a process called spalling, where the water seeps into the pores within concrete. At low enough temperatures meltwater containing salt that has seeped into the pores could start to freeze and thereby expand, thus cracking the concrete.
Most concrete will withstand a freeze cycle with normal water. However, as NaCl is a hygroscopicA substance that absorbs moisture from the air compound it increases the volume of water absorbed within the concrete by up to 10% thereby increasing the amount of expansion that occurs.
In colder climates, it might be worth looking at ice melt alternatives that don't freeze at lower temperatures.
Can I Use Water Softener Salt On My Driveway
Using water softener salt on your concrete driveway to melt snow or ice comes with certain risks. Because concrete is porous it will soak up some melted water, if there is a subsequent cold snap this water could freeze forcing it to expand and damage your driveway.
The more cracks that are in your driveway the higher the probability is for further damage when the temperature drops significantly.
How Long Does It Take For Salt To Damage Concrete
That is hard to say, while it could take a lifetime. If the concrete already is in a bad condition, one overnight drop in temperature could be enough to destroy your driveway beyond repair.
How To Stop Salt Damage To Concrete
Some measures could be taken to prevent spalling of your concrete during colder times. New concrete can be made to withstand water expansion through the use of air entrainment.
Because of the air bubbles within the concrete, it becomes more flexible making it less likely to crack during a freeze-thaw cycle.
How To Seal Concrete From Freeze-thaw Cycle Damage
It is possible to shield existing concrete from freezing damage by using a concrete sealant that will seal the pores within your concrete thereby preventing water from seeping into it.
Will A Ruptured Brine Tank Damage Your Concrete Floor?
As long as your water softener is not located in an area where temperatures drop below freezing during colder periods your floor will suffer no damage from a tank rupture.
The salt can, however, you might want to thoroughly rinse it off as it can irritate your skin or could cause harm to animal paws if around.