Concrete cracks and concrete fissures | Deterioration of a concrete floor

Concrete cracks or fissures are the most frequent damage to structural concrete elements, whether they are floors, columns, walls or beams. These are characterized by fractured lines, sometimes interconnected, which expose the interior of the concrete.

Beyond affecting the aesthetics of concrete, cracks commit the structural integrity of a building, so they require proper repair based on an accurate diagnosis of their causes.

Difference between cracks and concrete fissures

Most of the time the words cracks and fissures are interchanged and used equivalently, as a synonym, but in fact they are 2 different concepts.

To end the confusion, you should know that these, the cracks are harmful openings that appear in a structural element, developing throughout its entire depth.

Nevertheless, concrete fissures are small cracks at surface level, which mainly affect its finish, deteriorating the surface of the structural element.

Because of the similarity between cracks and fissures, width is generally used as a differentiation parameter to determine the difference between the two terms.

Types of concrete cracks, what types exist?

Usually, the classification of cracks in concrete is given in the context of floors. However, this classification can be a guide to different structural elements.

The main cracks in floors are:

Longitudinal cracks

These are cracks parallel to the main axis of the slab. They can develop from a transverse joint to the ends of the slab.

Transversal cracks

Unlike the previous ones, these cracks are perpendicular to the main axis, and can develop from a transverse joint to a longitudinal joint.

Block cracks

They occur when longitudinal and transverse cracks join to form an interconnected network, geometrically similar to a block.

Corner cracks

These cracks usually have a triangular shape in the floor slab. They generate a kind of block by interconnecting diagonal cracks. These can be longitudinal or transverse with an angle of inclination to the axis of circulation.

Causes that cause cracks in floors

There are many reasons for cracks in concrete floors. However, the most relevant are the following:

  • Overloads
  • Differential settlements
  • Earthquakes and other accidental solicitations
  • Errors in the construction processes or in the design of the structural element
  • Plastic shrinkage
  • Thermal fluctuations caused by environmental influences
  • Hydraulic retraction in hardened state
  • Steel corrosion
  • Expanding clays
  • Combined causes

How to repair cracks in concrete

Before turning directly to the crack repair methods, it is advisable to perform a diagnostic of the damage in order to determine its main cause.

Once the reason for the cracking has been detected, it is repaired. The repair works consist essentially of sealing the crack.

Depending on the intended use of the floor in the repaired area, either a rigid or elastic sealer will be used.

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