Concrete spalling–What causes it and how to prevent it


Concrete spalling will be visibly apparent by round or oval depressions along surfaces or joints of your concrete surfaces–like perhaps your driveway. Spalling could occur particularly if you have not used a concrete driveway sealer. Cracks, fissures, or huge dents on their surfaces not only look unsightly but can also be indicative of a broader problem underneath. Spalling occurs because water enters your concrete or bricked area and spalling could cause your reinforcing bars (rebars) made up of steel, to rust and expand. This could potentially threaten your entire foundation and could be costly to fix.


Causes 

One of the main reasons concrete surfaces end up spalling, apart from not using a good quality driveway sealer, is due to bleeding. Either not enough bleeding–or too much. Contractors who are hasty may not allow the newly placed concrete enough time to bleed. Bleeding is the process whereby free water in fresh concrete is pushed up to the surface,  due to the heavier more solid particles of water and cement settling on the bottom. Almost all freshly placed concrete bleeds and it is very important that this bleed water evaporates. If it is trapped near the top surface then the strength of your concrete is compromised and the moisture will cause endless problems. Your concrete can also bleed too much or too fast due to the bad proportioning of materials in the batch of concrete when it was mixed. There are methods to reduce bleeding in concrete and these include:


  1. Reducing water content
  2. Using finer types of cement
  3. Increasing fines in the sand (to absorb water sufficiently)
  4. Using supplementary cementitious materials
  5. Using air-entraining admixtures or additives


Driveway sealing - Protecting against wear-and-tear, weather, and more

Even concrete that went through the correct bleeding process could still end up spalling and/or scaling. To reduce scaling and/or spalling use the best driveway sealer–Pentra-Shield. This is a concrete surface hardening densifier with anti-scale and freeze-thaw protection. Pentra-shield will reduce porosity and increase the strength and durability of your concrete and thus prolong the life of your driveway or concrete surface.  It not only offers robust protection against freeze-thaw cycles but also protects against de-icing chemicals. To find out more on how to seal a driveway the right way contact  Convergent Concrete Technology today.

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