Major Reasons of Cracks in Concrete Construction
The crack in concrete construction can be a major issue. It can be prevented by taking the right measure well in advance.
There are various reasons for which cracks can be developed in concrete construction.
Causes for which Cracks developed in Concrete Structures
- Quality of Concrete – Quality of concrete depends upon its material. Therefore, it is needed to use only best quality construction material that reduces the risk of Cracks.
- Temperature Fluctuation – During the contraction materials heated up and gradually it cools down. This expansion and contraction with temperature change takes place of all structures cross sectional area.
- Creep Movement – If any slope is covered with loose it causes slow downward movement within. With the modern technologies frost heaving gets implemented to restrain cracks.
- Moisture – In construction due to differences in vapor pressure moisture movement happens in between moves through a porous medium. This movement affects concrete and result cracks.
- Reinforcement Corrosion – In due course of time it is natural to develop corrosion in reinforcement due to atmospheric reaction to it. There are other reasons to it too – Carbonation, High Chloride, Moisture reaction, Lack of proper measure during storage.
- Maintenance – If the proper care is not taken time to time then due to lack of maintenance can be another major cause for it.
- Design – Poor structural design & specification can be another major cause of it.
Different Types of Cracks in Concrete Structure
Plastic Settlement Cracking
At initial level when the concrete mix is not solid during that time this type of cracks form at the surface. After some hours of placement only it can be identified.
How to Prevent Plastic Settlement Cracking?
There are few ways that can prevent this type of Cracks in Concrete.
- By using High Quality Concrete Mix
- Using Shrinkage Compensating Admixture into Concrete Mix
- Controlling the vibration during construction
- Re-vibration of concrete after they are formed
Plastic Settlement cracking is a common error but it can be eliminated if the points mentioned above are followed properly.
Thermal Contraction Cracking
Thermal Cracking causes for massive temperature deviation in mass concrete. It appears on surface level after few days of formwork.
How to Prevent Thermal Contraction Cracking?
Thermal Cracking happens due to huge difference between the maximum temperature and minimum temperature range that occurs in concrete. The Designer and Contractors are mainly responsible to minimize this type of cracking by following the specifications limits and doing the temperature control on time.
- Usage of Port land Cement that generates relatively low heat.
- Avoid specifying an excessively low w/cm (water-cementitious materials ratio)
- Thermal Control measures has to be decided before starting the construction
- Using the cooling pipes if necessary during the cooling process.
Drying Shrinkage Cracking
Drying Shrinkage mainly occur for usage of more water in concrete mix. It can be reduce during the design stage:
How to Prevent Drying Shrinkage Cracking?
Drying Shrinkage Cracking can be reduced during the design stage.
- Provide sufficient movement joints
- Sufficient Crack Control Reinforcement can also reduce this type of cracking in concrete
- During the placement avoid adding additional water to the mix
Reinforcement bars are the main component that strengthens the structure because of superior bonding with concrete. Corrosion of TMT Rebar can be one of main issue if that is not taken care on time.
How to Prevent Reinforcement Corrosion?
Reinforcement corrosion can be one of the major issues that cause cracking to the structure. There are some methods that can stop developing corrosion in reinforced steel that are:
- Anti-Corrosion Coating on TMT Rebars before applying it to the construction site
- Corrosion Inhibitor Admixtures
- Cathodic Protection
But above all 2 things are most important to prevent corrosion. Water penetration and choosing the best quality TMT Bar those are highly corrosion resistant.
These are the major reason to develop cracks in concrete structure. It is important to take the precaution before it goes wrong. It is important to use only best quality construction material that strengthen the structure forever.