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The Basics of Self-Sealing

Written by Sarah Coull | May 22, 2013 8:06:02 PM
Left - concrete crack | Right - self-sealed crack

Self-Sealing is the ability to stop the flow of water by automatically closing cracks.

Krystol® Concrete Waterproofing self-sealing technology is based on principles that are very similar to the processes that occur during the hydration and hardening of concrete.

 

Importance of Self Sealing

  • Decreases water permeability (Increases corrosion resistance)
  • Re-seals new cracks that form during shrinkage, settling, etc.
  • Decreases long-term maintenance and repair costs

 

Four Main Mechanisms

  • Physical - Filler Effect and the swelling of Cement Matrix
  • Chemical - Continued Hydration and the precipitation of insoluble products

 

Filler Effect

  • Temporary Sealing - Debris carried into the crack by flowing water is deposited and clogs the flow of water.
  • Easily removable – high water pressure will wash away debris or degrade over time

 

Continued Hydration

  • Occurs when un-hydrated cement particles are exposed to water from the crack
  • The hydrating cement matrix seals by growing into the void between the crack walls
  • Ongoing process as long as un-hydrated cement is available

 

Precipitation

  • Main contributor to self-sealing
  • Formation of insoluble crystalline precipitates occurring over several weeks which deposits across the width of the crack
  • Krystol products act as a catalyst to accelerate the natural formation of precipitates.
  • KIM increases sealing capacity from 0.2 mm to 0.5 mm crack widths