Common Defects in Concrete and Their Causes

Concrete

Mixer of cement, sand, aggregate with water as per required proporion which is called as concrete, concrete is one of the most widely used construction material in worldwide, known for its strength and durability. Some common problems can occur in concrete due to various reasons, such as a poor design mix, using low-quality materials or unskilled workers, and environmental factors.

Here is some of most common concrete defects are stated below

1. Cracks in Concrete
2. Concrete Spalling
3. Efflorescence in Concrete
4. Delamination in Concrete
5. Crazing and Patterns in Concrete

1. Cracks in Concrete

Cracks in concrete is most common defect in concrete which is showed in below image. Cracks are separations or fissures that appear on the surface or inside concrete structures.
Most common of this effect is shrinkage during drying, thermal expansion and contraction, overloading, or improper curing, these cracks are reducing structural strength of concrete also due to this water and chemicals to penetrate inside the concrete

To Avoid Cracks in concrete:-

• Using of proper mix design will reduce the shrinkage.
• Install expansion joints at required areas to accommodate thermal movement.

2. Concrete Spalling

Spalling in concrete is also one of the common defect, happens when the surface of the concrete breaks apart or peels off. This issue will occur without any major external causes like accidents or fires. It is usually caused by factors such as water penetration, temperature changes, or rusting of steel inside the concrete, which weakens the structural strength & durability of concrete

To Avoid spalling in concrete:-

• To make an waterproofing in first floor slabs where water using continuously such as kitchen or bathroom because penetrating of water mostly happen in this areas.
• Use air-entrained concrete in freeze-thaw environmental areas
• Protect reinforcement steel with proper coverage (cover block).

3. Efflorescence in Concrete

Concrete efflorescence happens when soluble salts are carried to the surface by internal moisture. When the moisture is evaporate the salt to appear like a powdery appearance in the concrete surface like shown in image

To Avoid Efflorescence in concrete:-

• Using a protective coating over the concrete to helpful to avoid this issue
• Cure the concrete properly after pouring. This helps to prevent excessive moisture loss and keeps the concrete hydrated, reducing internal stress.
• Use clean, potable water with low salt content for mixing the concrete.

4. Delamination in Concrete

Concrete delamination is the separation of the Top or base layer (concrete cover area) at the surface, creating an unbounded of concrete from the rest of the structure. This creates a weakened area where the concrete is essentially detached, Due to this reinforcement steel will be visible on concrete. Delamination is caused by many reasons such as improper mix design, poor material & workmanship, over water content while mixing of concrete also improper compaction while casting of concrete etc…

To Avoid Delamination in Concrete:-

• Use an proper compaction techniques while concrete casting time
• Avoid usage of poor quality of material and manpower
• Avoid over-finishing during placement
• Use an proper mix design and water

5. Crazing and Patterns in Concrete

Crazing in concrete refers to a pattern of narrow, shallow cracks that are interconnected, often forming closed polygons or a network. This can appear within a few days of casting, though it can occur at any time if the right climatic conditions are present. Crazing is typically caused by rapid drying of the concrete surface, often due to factors like high temperatures, low humidity, or a lack of moisture during the curing process.

To Avoid Crazing and Patterns in Concrete:-

• Protect concrete from extreme environmental conditions during and after construction.
• Use high-quality materials and follow proper mix design.
• Ensure skilled labor during mixing, placing, and finishing.
• Provide adequate curing to avoid rapid drying.

Frequently Asked Questions (FAQ) about Concrete Defects

1. What is concrete in construction?
2. What are the most common concrete defects?
3. What causes cracks in concrete?
4. How can cracks in concrete be prevented?
5. What is concrete spalling, and what causes it?
6. How can concrete spalling be avoided?
7. What is efflorescence in concrete, and how does it occur?
8. How can efflorescence in concrete be prevented?
9. What is concrete delamination, and what causes it?
10. How can delamination in concrete be avoided?
11. What causes crazing and patterns in concrete?
12. How can crazing and patterns in concrete be prevented?