Crack On Concrete and its major Causes
Crack on Concrete: Crack is a complete or incomplete separation of concrete into more parts produced by breaking or fracturing. Cracks are one kind of universal problems of concrete construction as it affects the building and it also destroys the wall’s integrity, affected the structure safety, and even reduce the durability of the structure.
Types of Cracks in Structure: The cracks appear in the structure, at a certain period of time. Most commonly used cracks with their respective causes and precaution.
1. Shrinkage Cracks
Concrete has its own nature in dry or wet. They expand when they absorb water/moisture and shrink when dray. Shrinkage cracks occur due to change in the moisture of the concrete mix. Drying is the main cause of concrete shrinkage cracks.
2. Hairline Cracks
Hairline cracks may develop in the concrete foundation as the concrete cures. Hairline cracks do not cause problems with the stability of the foundation but do cause leakage problems.
3. Settlement Cracks
Settlement cracks may appear when the underlying ground has not been compacted or appropriately prepared or if the soil was not of the proper consistency. A settlement crack may also appear as a random crack above areas where the soil of the subgrade was uneven after the concrete was poured.
Major Causes of Cracks:
Cracks can occur due to various reasons chemical reactions in construction materials, foundation movement and settling of structure, change in temperature and climate, environmental stresses like the nearby movement of transportation, earthquakes, etc. Faulty and defective designs, proper quality materials, incorrect methods of construction, weather, and loads of wear, and tear can create cracks.
1. Initial Shrinkage
Building material like brickwork, concrete, etc. shrinks in the beginning. Shrinkage Cracks on structure when cement content increases with the richness of mix, the water quantity used in the mix, and the size of the aggregate.
2. Thermal Movement
All building materials expand on heat and contract on cooling. The thermal movement in the components of structure creates cracks owing to the tensile of shear stress. But again, the scale of movement depends on their molecular structure and other properties. Thermal Changes are the strongest causes of cracks in structure and demand attention.
3. Chemical Reaction
A chemical reaction in materials increases their overall volume and internal stress which results in cracks. The material used in construction weakens due to Chemical Reactions.
4. Foundation movement and settlement of soil
Shear cracks happen due to huge deferential settlement in the foundation, structures constructed on soil whereas absorbing moisture and shrink on drying due to change in the moisture content of the solid and highly prone to cracking.