Rice husk ash is a byproduct of burning rice husks. It can be mixed with concrete to increase workability and improve strength and durability properties. The document discusses how rice husk ash concrete is produced by partially replacing cement with rice husk ash. It provides details on the chemical and physical properties of rice husk ash and its effects on concrete properties like strength, permeability, and setting time. Rice husk ash concrete is found to be stronger and more resistant to chloride penetration compared to ordinary concrete. Additionally, using rice husk ash in concrete can help reduce carbon dioxide emissions from cement production.

1. RICE HUSK ASH
Pimpri Chinchwad Education Trust’s
PIMPRI CHINCHWAD COLLEGE OF ENGINEERING
Department of Civil Engineering
By PAYAL INAMDAR
FYMCI2104
SUB:- PROFESSIONAL
ELECTIVE LAB
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2. WHAT IS RICE HUSK ASH ( RHA) AND HOW IT
IS MADE, WHERE IT IS USED?
▪ Rice husk ash is a product of burning rice husk. The
burned remains are then mixed with concrete to
increase the workability of the concrete.
▪ Rice husk ash concrete shows better bond strength
when compared to Portland cement. The compressive
strength, split strength, and flexural strength of the
material are greater than ordinary concrete
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3. Concrete materials
▪ Concrete mixtures to be examined were made in the laboratory
using the following materials
▪ Cement --1.5% (rice husk ash—25%)
▪ Gravel --ca=1.5%,fa=3%
▪ Plasticizer for water retarders
▪ Rice husk ash—25%
▪ Water –0.45%
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4. https://youtu.be/RRJxiQYh7lM
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Video link:-

5. Chemical and Physical Properties of Rice Husk Ash (RHA)
Chemical Properties
• SiO2: 78–86
• Al2O3: 1–2.0
• Fe2O3: 16–1.85
• CaO: 55–4.81
• MgO: 35–4.5
• SO3: 24–1.18
• Na2O: 1–1.14
• K2O: 54–3.68
• Loss in ignition: 4–8.55
Physical Properties:
The physical properties of rice hull ash vary depending on
the temperature of burning and grinding of the rice husk
• Color: Grey
• Specific Gravity: 05-2.53
• Specific Surface Area: 40-100 m2/g
• Bulk Density: 200-300 kg/m3
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7. Effect of Rice Husk Ash on the Properties of
Concrete
▪ 01. Setting Time of Concrete
‘Namrata Verma et al.’ (Published in International Journal of Engineering
Research & Technology (IJERT)) conducted an experiment to check the
behavior of concrete containing RHA for initial and final setting time. They
concluded that the initial setting time of RHA concrete increases and the final
setting time decreases with increase in RHA content. This behavior may be due
to the low rate of hydration in the paste containing RHA.
▪ 02. Workability
According to ‘Mehta P.K.’ (Published in Proceedings of the CANMET/ACI
International Symposium on Advances in Concrete Technology), higher the
percentage replacement of cement with RHA, lower is the workability of fresh
concrete mix. However, the workability of the concrete can be improved by the
use of water reducers or superplasticizers.
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8. ▪ 03. Strength
Rice husk ash concrete improves the compressive strength of the concrete. ‘Syed Mehdi Abbas
et al’ (Published in International Journal of Scientific & Engineering Research) carried out tests to
find out the ideal RHA replacement level with Ordinary Portland cement to achieve the maximum
compressive strength of concrete. They casted concrete cubes with the replacement of RHA at
5%, 10% and 15% with OPC and concluded that the concrete containing 10% of rice hull ash
showed the maximum compressive strength. It is because of amorphous silica and the fine
particle size of rice husk ash.
▪ 04. Permeability and Chemical Stability
The resistance to the penetration of chlorides and other chemicals is the most important factor
which decides the durability of concrete. Addition of rice hull ash in concrete imparts pozzolanic
effect. It reduces a large amount of calcium hydroxide and makes extra C-S-H gel. Hence it
improves the concrete matrix, makes it dense resulting in the lower permeability of concrete and
high resistance to the penetration of chlorides and other chemicals.
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9. Carbon credits
▪ The production of 1Tons of cement contributes to 1 tons of co2 in
atmosphere
▪ Worldwide 7% of carbon dioxide emission for production of OPC
▪ The utilization of RHA in concrete production is solution to reduce
the cement
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10. Uses of Rice Husk Ash
The main uses of rice husk ash are as follows:
• Rice hull ash is used to make high-performance concrete.
• Rice hull ash is used as an insulator.
Rice hull ash is also used in:
▪ In a ceramic glaze In speciality paints
• In roofing shingles Flame retardants
• In waterproofing chemicals In oil spill absorbents
• In insecticides and biofertilizers etc.
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11. How to Use Rice Husk Ash?
There are two methods for using rice husk ash in the concrete.
• The rice hull ash can be blended with ordinary Portland cement
• Ordinary Portland cement can be replaced by rice husk ash with
definite percentage.
The various experimental investigations disclosed that incorporation of
rice hull ash as partial replacement of cement improves the
compressive strength of concrete. The replacement percentage of rice
husk ash varies from 5% to 30% by the weight of cement.
▪ The current market rate of rice husk ash concrete is
Rs.2800/cubic meter (minimum) to Rs.3050/cubic meter
(maximum).
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12. Advantages of Rice Husk Ash
• Rice husk ash provides good compressive strength to the concrete.
• It is a by-product; hence, it helps in cutting down the environmental pollution.
• The high silica content makes it a good supplementary cementitious material or pozzolanic
admixture.
• The density of concrete containing rice husk ash is similar to the normal weight concrete;
hence, it can also be used for the general-purpose application too.
• The impervious microstructure of rice husk ash concrete provides better resistance to the
sulphate attack, chloride ingress, carbonation etc.
• Rice hull concrete has good shrinkage property and increases the durability of concrete.
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13. Disadvantages of Rice Husk Ash
▪ By the use of rise husk ash, concrete progressively becomes unworkable.
▪ Hence water-reducing admixtures should be used to obtain workable concrete
for the ease of placement and compaction of concrete.
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14. CONCLUSION
▪ To study the effect of RHA
▪ The properties of concrete containing RHA had been successfully
studied.
▪ The use of RHA in civil construction, besides reducing the
environmental polluters’ factors, may bring several improvements
the concrete characteristics.
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15. Reference
▪ M.S.SHETTY CONCRETETECHNOLOGY
▪ Effect of Rice Husk Ash on Cement Mortar and Concrete. Sudisht
Mishra, Prof (Dr.) S.V. Deodhar.
▪ Effect of Rice HuskAsh on Lime Stabilization. Dr. J. N. Jha (Member)
K. S. Gill
▪ Effect of Rice Husk Ash on Cement Stabilized Laterite. MUSA
ALHASAN
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