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It is always important to maintain thorough and sufficient techniques for pouring new ready-mix concrete. When pouring new concrete in the early spring, slabs can be more prone to shrinkage cracking than usual. To maximize the quality of your next Des Moines area ready-mix concrete pour, make sure you know what shrinkage cracking is, why it happens, and what to do about it.

What is shrinkage cracking?

When a slab of freshly poured concrete begins to cure, the moisture present in the mix must dissipate. This causes the concrete to shrink and harden. Whenever there is excess water or other conditions that cause this process to happen unevenly, shrinkage cracks may appear on the surface of your concrete.

Why is the top of my concrete slab cracking?

Shrinkage cracking is a somewhat unfortunate and inevitable occurrence when pouring new concrete. This occurs for many reasons, but for early spring pours in particular the problem can be due to the fact that the bottom of a new slab sits on cold ground and takes a long time to cure, whereas the top of the slab is subject to warmer temperatures and wind that causes it to dry and crack. Other contributing factors to shrinkage cracking include:

  • Presence of excess water in the mix
  • Improper preparation of the subgrade (pay attention to the compaction and moisture you are pouring on)
  • Poor or improper use of concrete reinforcement
  • Lack of control joints
  • Poor timing of saw cuts
  • Insufficient depth of joint cuts
  • Insufficient finishing techniques

How to prevent or minimize concrete shrinkage cracking

  1. Plan for the weather. It may seem obvious not to pour new concrete during a rainstorm, but it can be just as damaging to your end product if the newly poured concrete is subject to extreme temperatures.
  2. Beware of adding moisture. The benefit of scheduling your ready-mix concrete delivery with Liberty Ready Mix is that the concrete mixture will already be mixed to ideal moisture specifications. However, adding water to the mix or using improper pouring or finishing techniques could cause an unbalanced water content leading to shrinkage cracks occurring. 
  3. Prepare your subgrade. Pouring the mixture on top of a subgrade that is properly compacted and meets ideal moisture content will make a big difference in the occurrence of shrinkage cracking. 
  4. Consult your ready-mix provider. While planning for your concrete project, talk with your Liberty Ready Mix representative to ensure you have all of the information needed to achieve the best results from our ready-mix delivery.

Talk to a Des Moines Ready Mix Professional & Schedule Delivery 

Liberty Ready Mix services the Des Moines area with ready mix concrete to meet residential, commercial, and industrial needs. Contact us today to get started on your project.