Replacement of Cement by Rice Husk

1. USE OF RICE HUSK ASH IN CONCRETE (RHA)
Presented by :-
G . Tharunkumar
Dept. Of Civil Engineering,
G. Pullaiah College of Engineering and Technology.

2. CONTENT
 1 Introduction
 . What is RHA
 3. Properties of RHA
 4. RHA in Concrete Production
 5.Advantages and Disadvantages
 6.Conclusion

3. 1.INTRODUCTION
 Rice husk is an Agricultural waste product which is produced in Millions
of tons. Approximately for 100Kg of rice ,20Kg of rice husk is obtained .
Rice husks contain Organic substance and 20% of Inorganic material.
 Physical characteristics and chemical composition of mineral admixtures
can be fulfilled by burning rice husk into RICE ASH.
 Combustion of rice husk at controlled temperature produces RHA that has
amorphous silica content and large surface area.

4. 2.What is RHA ?
 Rice husk is an “pozzalonic material” . It is having different types of
physical & chemical properties . The product obtained by from RHA is
identified by trade name silpoz which much finer than cement.

5. 3a.Physical properties of Rice Husk Ash:-
S.no Particulars properties
1 Colour Gray
2 Shape Texture Irregular
3 Mineralogy Non Crystalline
4 Particle Size <45micron
5 Odour Odourless
6 Specific gravity 2.3
7 Appearance Very fine

6. 3b.Chemical properties:-
S.no Particulars Proportio
n
1 Silicon dioxide
(sio2)
86.96%
2 Aluminium oxide (Al2o3) 0.2%
3 Iron oxide
(Fe2o3)
0.1%
4 Calcium oxide
(cao)
0.3-2.2%
5 Magnesium oxide (Mgo) 0.2-0.6%
6 Sodium oxide
(Na2o)
0.1-0.8%

7. 4. RHA in Concrete production
a. In convectional concrete:
 As RHA contains high amount of amorphous
silica .It is can be used as a partial replacement
of cement in convectional concrete to develop its
strength and durability properties.
 The RHA will be perfect substitute of silica
fume for making special concrete mixes.
 From experiments it is found that replacement of
RHA below 20% in concrete gives neither
gives strength in concrete nor durability

8. 5. Advantages
• Higher the strength as it provides an additional CSH
Gel.
• Reduces permiability hence resistance against the
chloride attack increases.
• As it consumes lime content of the concrete , Sulfate
attack doesn’t attack.
• The bleeding of concrete doesnot occur’s

10. Compressive strength of RHA Concrete
 The compressive strength of RHA concrete
was investigated at 7,14,21,28 days curing
age.
 The summary of this result are graphically
represented Graphically below for
percentages of RHA

11. Graphical representation

12. Disadvantages
 The water for convectional concrete is increased.
 Choice of good quality RHA which is major factor
for strength and durability.
 We cant use only RHA as a source of Materialin
Geopolymer concrete.

13. 6.Conclusion
 The RHA is very good substitute of cement in both
convectional concrete and in Geopolymer concrete.
 The RHA can be used as a good pavements for improving the
shear strength of pavements.
 Use of RHA helps in reducing the co2 emission,
creating a better environment controlling Global warming

14. As a Civil Engineer ,I request
all you to use eco-friendly
materials and help in creating
A better environment