Causes of cracks in concrete

In this exclusive civil engineering article, you will learn the reasons for cracks inside concrete.

Cracks in concrete happen due to the following facts :-

Shrinkage: It is mostly found in hardened concrete. In drying shrinkage, the volume of concrete is slowly reduced and when the element is detained against free movement, tensile stresses are produced to create cracks.

Variation in temperature: Changes in temperature (whether too hot or cold) causes differential volume change in concrete. When the tensile strain volume of concrete goes beyond limit because of the differential volume change, the cracks occur in concrete.

Chemical Reaction: The cement has alkaline nature and it makes reaction with the carbon dioxide (CO2) exist in atmosphere. As a result, the volume of the materials is raised significantly and cracks occur in concrete.

Inferior Construction Method: It involves inclusion of extra water to the mix, scarcity of curing, weak compaction with low-grade materials, placing of construction joints improperly. All these factors lead to cracking in concrete.

Faults in design & detailing: It comprises of insufficient amount of reinforcement, inaccurate design of foundation, precast members and slabs, choosing materials inappropriately, scarcity of adequate construction joint. The cracks in concrete occur due to these factors.

Construction Overloads & Detachment Of Formwork Before time: The loads generated in the structure throughout construction also cause cracking specifically at the initial phase when the formwork is detached beforehand.

Elastic Deformation And Creep: While loading, elastic deformation is produced for the various elements of the building like wall, column, beam, slab etc. It is based on the type of building materials utilized in construction like bricks, cement concrete blocks etc. Due to this unusual deformation of concrete, cracks occur.

Erosion Of Concrete: The erosion of steel creates lots of iron oxides and hydroxide which contain a larger volume as compared to the volume of metallic iron. As a result the volume is raised and cracks occur.

Video Source: Civil Study