Sanjeet Project of ksbd book sjdhrjekjdjkwwndbndddmwmd

Project ppt

1. UNDER SUPERVISION OF :
Dr. Sachin Tiwari
Professor ,GLBITM
Session 2023-2024
Topic-Examine the strength and durability of concrete using
Fly Ash
PRESENTED BY :
Sanjeet Kumar
Vishal Preet Nishad
Atul Kumar Verma
Fatima Sugra

2. Contents:
●Introduction
●Definition
●Properties of Fly Ash concrete
●ClassificationofFlyAsh
●AdvantagesandDisadvantages
●MaterialsusedinFlyAsh
●Workability
●SettingTime

3. INTRODUCTION
•Fly ash concrete is an eco-friendly construction material in which fly
ash replaces a part of Portland cement.
•But IS:456 —2000 and ACI:318 allows replacement of OPC by Fly
ash up to 35% only as binding material.
•High volume fly ash concrete is a concrete where a replacement of
about 35% or more of cement is made with the usage of fly ash.

4. Definition
➢Fly Ash is thefinallydividedbyproduct resulting from the combustion of
coal in power plants.
Properties
➢It contains large amounts of silica, alumina and small amount of unburned
carbon, which pollutes environment.
➢It is grey in color and alkaline in nature.
➢The particle size ranges between 1-100 microns.
➢The specific gravity of FA lies between 1.9 and 2.8 (generally 3.15 for
Cement) .

5. ➢The surface area is typically 300—500 m2/kg, although some FA can have
a surface area as high as 700 m2/kg ( around 330 m2/kg for Cement ).
➢The mass per unit volume including air between particles ( density ) can
vary from 540 to 860 kg/m3.

6. Classification of Fly Ash
➢Two classes of fly ash are defined by ASTM C618:
▪Class F fly ash
▪Class C fly ash
➢This classification is based on the chemical composition of FA i.e. the sum
of silica, alumina and iron oxide percentages in the FAI being:
▪minimum of for a
Class F
▪minimum 50% for a
Class C

8. WHY TO USE FLY ASH?
➢Being a pozzolanic, it can actually replace a part of Portland cement
➢Results in more durable concrete
➢High ultimate strength
➢Improves workability
➢Improves cost economy of concrete
➢Reduction in heat of hydration
➢Decreases density of concrete
➢More environment friendly concrete

9. Disadvantages of Fly Ash Concrete
➢Longer drying and setting times
➢Delayed setting in cold climates
➢Slow strength development in cold climates
➢Air-entraining admixtures may be necessary
➢Requires safe disposal according to EPA regulations

10. Materials used in Fly Ash concrete
➢Fly Ash
➢Fine and Coarse Aggregate
➢Cement
➢Water

11. Fly Ash
Fly ash is the finely divided residue that results from the combustion of
pulverized coal and is transported from the combustion chamber by
exhaust gases.
Aggregate
Aggregates are the inert materials that are mixed in fixed proportions
with a Binding Material to produce concrete.

12. Cement
Cement is one of the most important building materials, is a binding agent that
sets and hardens to adhere to building units such as stones, bricks, tiles, etc.
Water
Water is added to cement, it creates a paste that glues all of the aggregates
together. The cement paste then undergoes a chemical process known as
hydration, this chemical reaction is what allows the concrete to harden and
become strong and solid.

13. Workability
Reduction in water requirement is mainly due to three mechanisms:
➢Fly ash gets absorbed on the surface of oppositely charged cement particles
and prevent them from flocculation, releasing large amounts of water,
thereby reducing the water-demand for a given workability.
➢The spherical shape and the smooth surface of fly ash particles help to
reduce the interparticle friction and thus facilitate mobility.
➢Due to its lower density and higher volume per unit mass, fly ash is a more
efficient void-filler than Portland cement.

14. Setting Time
➢High volume of fly ash extends both the initial and final setting time of
concrete
➢The impact of fly ash on the setting behavior of concrete is dependent on:
➢composition and quantity of fly ash used
➢amount of cement
➢water to cementitious material ratio
➢concrete temperature

15. THANK YOU