Usually, Four types of cracks are found in reinforced concrete column which range from diagonal cracks, horizontal cracks, splitting cracks, corrosion cracks. The cracks happen in columns due to improper design, defective construction or overloading, erosion of reinforcement, isolated settlement of foundations, creep and shrinkage.
Cracking in reinforced concrete column may result in loosing of strength, consistency, longevity, and adversely impact aesthetics.
Types of cracks found in concrete columns:
1. Diagonal Cracks: If there are diagonal cracks in reinforced concrete columns, they encircle the whole face of column anywhere along its height. Because of insufficient load bearing strength of the columns, inadequate cross-section and inadequate reinforcement steel.
Diagonal Cracks significantly impact the structural soundness and therefore it should be monitored carefully.
2. Horizontal Cracks: Horizontal crack in reinforced concrete column is generally found at the beam-column joint, and on column face where tensile stress is massive. Columns with insufficient moment resistance strength, inadequate reinforcements, or disposition of installed reinforcement may lead to horizontal cracking owning to the effect of shear force and direct load and uniaxial bending.
Finally, horizontal cracks significantly decrease the shear strength of the column and as a result there is high risk of failure. So, it should be dealt with instantly and carefully.
3. Splitting Cracks: Splitting cracks in reinforced concrete column belong to short parallel vertical cracks having non-uniform width. These types of cracks may occur in columns with insufficient steel reinforcement, and low concrete quality. Splitting cracks in concrete columns originated because of attaining its maximum load bearing strength.
The ultimate Load bearing strength of the column is exceeded when concrete cross section is not enough or reinforcement ratio is inadequate or combination thereof.
4. Corrosion Cracks: Corrosion cracks in concrete columns are formed along the line of reinforcements. These types of cracks are usually homogeneous in width and expand as the column is ageing.
Probable reinforcement erosion and insufficient bond among the concrete and steel bars lead to erosion reinforcement in concrete columns. If these types of cracks are not dealt with properly, the erosion of reinforcement will be increased at a rapid rate.