👉What Is Fly Ash
💫Fly Ash is a fine powder that comes from burning pulverized coal in power plants.
⏺It is a by-product collected from the flue gases.
⏺In construction, it is used as a supplementary cementitious material (SCM) — meaning it behaves like cement when mixed with water.
✅ What Fly Ash Does
⏺Fly ash contains silica (SiO₂) and alumina (Al₂O₃) that react with the lime (Ca(OH)₂) released from cement hydration and form additional calcium silicate hydrate (C-S-H) — the main strength-giving compound of concrete.
⭐ Importance of Fly Ash in Concrete
1️⃣ Improves Workability
⏺Fly ash particles are spherical and smooth → they act like tiny ball bearings, making fresh concrete easier to mix and place.
2️⃣ Increases Long-Term Strength
⏺The pozzolanic reaction continues for a long time and forms extra C-S-H → results in higher strength after 28 days and beyond.
3️⃣ Reduces Heat of Hydration
⏺Good for mass concrete (dams, thick foundations) because it minimizes temperature cracks.
4️⃣ Improves Durability
⏺Fly ash concrete is more resistant to:
Sulphate attack
Chloride penetration
Alkali-silica reaction (ASR)
Permeability (less water enters)
5️⃣ Reduces Cement Consumption
⏺Replacing 15–30% of cement with fly ash:
Saves cost
Makes concrete more sustainable
Reduces CO₂ emissions
6️⃣ Increases Workability Retention
⏺Slower setting → useful for hot weather concreting.
7️⃣ Improves Finish
⏺Makes surface smoother and reduces bleeding & segregation.
⚠️ Disadvantages (for full understanding)
❇️Slower early strength (first 3–7 days) compared to pure cement.
❇️Not suitable in very cold weather without special care.
Quality depends on source; low-quality fly ash reduces benefits.
🎯 Simple Definition
⏺Fly ash is a cement-like powder from coal power plants used in concrete to improve strength, durability, workability, and reduce cost.
@etconp
💫Fly Ash is a fine powder that comes from burning pulverized coal in power plants.
⏺It is a by-product collected from the flue gases.
⏺In construction, it is used as a supplementary cementitious material (SCM) — meaning it behaves like cement when mixed with water.
✅ What Fly Ash Does
⏺Fly ash contains silica (SiO₂) and alumina (Al₂O₃) that react with the lime (Ca(OH)₂) released from cement hydration and form additional calcium silicate hydrate (C-S-H) — the main strength-giving compound of concrete.
⭐ Importance of Fly Ash in Concrete
1️⃣ Improves Workability
⏺Fly ash particles are spherical and smooth → they act like tiny ball bearings, making fresh concrete easier to mix and place.
2️⃣ Increases Long-Term Strength
⏺The pozzolanic reaction continues for a long time and forms extra C-S-H → results in higher strength after 28 days and beyond.
3️⃣ Reduces Heat of Hydration
⏺Good for mass concrete (dams, thick foundations) because it minimizes temperature cracks.
4️⃣ Improves Durability
⏺Fly ash concrete is more resistant to:
Sulphate attack
Chloride penetration
Alkali-silica reaction (ASR)
Permeability (less water enters)
5️⃣ Reduces Cement Consumption
⏺Replacing 15–30% of cement with fly ash:
Saves cost
Makes concrete more sustainable
Reduces CO₂ emissions
6️⃣ Increases Workability Retention
⏺Slower setting → useful for hot weather concreting.
7️⃣ Improves Finish
⏺Makes surface smoother and reduces bleeding & segregation.
⚠️ Disadvantages (for full understanding)
❇️Slower early strength (first 3–7 days) compared to pure cement.
❇️Not suitable in very cold weather without special care.
Quality depends on source; low-quality fly ash reduces benefits.
🎯 Simple Definition
⏺Fly ash is a cement-like powder from coal power plants used in concrete to improve strength, durability, workability, and reduce cost.
@etconp
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