You may have heard once or twice about needing to bring concrete to SSD conditions. But what is SSD? Why is it an important condition for concrete? And how to achieve it? This is what we will discuss today!
To start, what is SSD?
SSD is an abbreviation for the term saturated-surface-dry. It’s referring to a condition that concrete needs to be in sometimes.
Saturated-surface-dry means ensuring that the outer surface of the concrete is only slightly damp with no free water remaining. It should be as if that surface had been dried with a towel. Meanwhile, the concrete pores should be saturated with water to a depth of several millimeters.
As we now know what SSD is, why is it important?
SSD is a condition you should give your concrete when you want to apply a cement product to the concrete’s surface. if you want to repair the surface with cementitious grout or a similar product, you’ll need the surface to be in SSD condition.
Ensuring your concrete surface is in a saturated surface dry (SSD) condition during the application of cement products is important. Without it, water absorption by the concrete from the intended repair material can happen. That in turn can lead to an excessive amount of shrinkage and cracks.
However, if your concrete does have the right SSD condition, then you can avoid that concern. The water of the repair mixed material will not be absorbed by the concrete substrate being repaired. A good bond strength for the repair material will be enhanced in addition to proper cure & hydration of cementitious repair material. And a strong and lasting bond between the repair material and the host concrete substrate is one of the crucial aspects of the durability of concrete repairs.
If You Want to Achieve SSD, We Have a Couple of Recommendations
Your initial step should be to clean the surface. That means removing defects, paint, dirt, sealers, form release agents, laitance, other contaminants, and debris from the concrete surface you want to repair.
Then the surfaces must be pre-wetted to achieve a Saturated Surface Dry (SSD) condition after cleaning using a hose or bucket of water with a mortar brush to dampen the repair substrate. They will then use the mortar brush to help remove excess water from low spots in the substrate as free water at the surface must be avoided because it can impair the bond at the interface. Once the surface shows signs of drying but is not completely dry and there is a darker color compared to the dryer substrates, you know you've got an SSD, and the mortar application is ready to begin.
Alternatively, to SSD condition, installers can use an approved bonding agent from Uniguard products line such as Admix SBR or Admix Bond Plus.