1. FLY ASH USE AS A REPLACEMENT OF CEMENT
PREPARED BY, ARNAB SAHA.
STREAM: CIVIL ENGG(6THSEM).
ROLL NO:11.
COLLEGE: SUPREME KNOWLEDGE FOUNDATION GROUP OF INSTITUTIONS.

2. ORIGIN OF FLY ASH
The fly ash became available in coal based thermal power station in the year 1930 in u.s.a.in r.e. Davis and his associated at university of California published research details on use of fly ash in cement concrete.

3. WHAT IS FLY ASH?
It is a kind of ash is extracted from flue gases through Electrostatic Precipitator in dry form. This ash is fine material & possesses good pozzolanic property.

4. Type of fly ash

5. Properties of fly ash

6. Fly Ash Concrete
In commercial practice, the dosage of fly ash is limited to 15%-30% by mass of the total cementitious material, which has a beneficial effect on the workability and cost economy of concrete but for improved durability against sulfate attack, alkali-silica expansion, and thermal cracking, larger amounts of fly ash, are necessary.

7. FLY ASH EFFECTS ON CONCRETE
WORKABILITY IS IMPROVED.
INCREASES THE STRENGTH OF CONCRETE.
THE EARLY AGE STRENGTH MAY BE LESS BUT ULTIMATE STRENGTH IS MORE.
RESIST SULPHATE ATTACKS.
DECREASED PERMIABEILITY.
INCREASED DURABILITY.
REDUCED HEAT OF HYDRATION,ETC.

8. USES OF FLY ASH
MANUFACTURE OF PORTLAND POZZOLANA CEMENT &PEFORMANCE INPROVER IN O.P.C.
PART OF REPLACEMENT OF O.P.C CEMENT.
MANUFACTURES OF ASH BRICKS AND OTHER BUILDING PRODUCTS.
CONSTRUCTION OF ROAD EMBANKMENTS ,STRUCTURAL FILL AND LOW LYING AREA DEVELOPMENT.

9. USES OF FLY ASH in field

10. WHY USE FLY ASH AS A REPLACEMENT OF CEMENT
TO GET-
GOOD STRENGTH.
BETTER WORKABILITY.
HIGH DURABILITY.
TO REDUCE-
HEAT OF HYDRATION.
PERMIABILITY.
ALKALI AGGREGRATE REACTION AND ALSO RESIST THE SULPHATE ATTACK ETC.

11. How fly ash CAN BE USED in concrete

12. HOW FLY ASH EFFECT ON STRENGTH OF CONCRETE

13. HOW WORKABILITY WILL IMPROVE?
Fly ash particles are generally spherical in shape and reduces the water requirement for a given slump. The spherical shape helps to reduce friction between aggregates and between concrete and pump line and thus increases workability and improve pumpability of concrete. Fly ash use in concrete increases fines volume and decreases water content and thus reduces bleeding of concrete.

14. HEAT OF HYDRATION OF FLY ASH CONCRETE

15. Table T3.1: Mix Proportion and Fresh Properties of different M20 concrete mixes having cementitious material content 350 Kg/m3 made with O.P.C
Mix No.
Fly Ash %
Cement
Aggregate
W/CM
WRA
L/m3
C.F.
Slump mm
Coarse
kg/m3
Fine
OL-0
100
1217
745
0.50
3.0
0.94 75
OL-30 30 70
0.48
1.8
105
OL-40 40 60
0.46
3.1
0.95
OL-50 50
0.43
3.8
0.92 95

16. High volume fly ash concrete

17. Why use high volume fly ash concrete?
FOR GETTING GOOD STENGTH AND DURABILITY .
THE COST OF THE CEMENT WILL REDUCE.
AND IT IS VERY ECO FRIENDLY ALSO.

18. COST GRAPH

19. Disadvantages

20. CONCLUSION
The long term strength of the concrete containing fly ash is higher than that of control concrete without fly ash.
The fly ash concrete shows lower water permeability compared to that of control concrete.
For similar cementitious material content and similar range of slump, the use of fly ash (0 to 50 %) decreased the water-to-cementitious-material ratio in general.

21. Any quesTion?
THANK YOU….