This document summarizes a study on the effect of adding wood waste ash on the compressive strength of concrete. The objectives were to study how wood ash replacement of cement affects compressive strength and workability. Concrete mixes with 0%, 10%, 20%, and 30% cement replacement were tested. Results showed workability decreased with higher ash content. Compressive strength also decreased as ash content increased, with the 10% mix showing only a minor decrease compared to the control mix. In conclusion, wood ash can replace some cement but higher replacements significantly reduce compressive strength.

1. Effect of Addition of Wood Waste
Ash on Compressive Strength of
Concrete
 Guided By:
 Dr. Rakesh Kumar
Professor, Dept. of Civil
Engineering
 Er. Jameela Qasim
 Roll No.17018003
 M.Tech Civil “CTM”

2. Contents
Introduction
Objectives
Methodology
Materials Used
Material Test Results
Details Of Concrete Mix
Result And Discussion
Conclusions

3. Introduction
 The expenditure on traditional materials used in construction is continued to
increase as the major percentage of the population continues to fall below the
poverty line. Hence, several research persons are working on to use alternative
material in place of normal traditional material to bring down the expenditure to be
spent on building material by using material, which is available in surrounding in
construction work.
 Now a days ecologists and agriculturists are facing big problem of disposing waste
substance. Disposal of waste materials is also a threat faced by industries
 Research persons found one of the solutions to dispose the waste substance as a
material used to fill in concrete production, by which both structural engineer and
ecologist’s gets solution in disposal of waste and increase of performance of
concrete to meet the structural needs.
 Concrete is a composite material that consists of binding material, water, fine
aggregates and coarse aggregates.
 Raising prices of building construction materials have increased the demand for
finding alternatives.
 In this project waste material used is wood waste ash.

4. Wood ash
 Wood ash is the residue powder left after
the combustion of wood
 It is grey in colour and alkaline in nature
 Wood ash concrete is an eco-friendly
construction material in which wood ash
replaces a part of Portland Cement.
 In the current trend, approximately 70% of
wood ash is land filled, 20% tends to be used
as a soil supplement in agriculture and 10%
are employed as other uses mainly in metal recovery
and pollution control.
 Wood ash has a huge capability for use as mineral admixture and
activator in cementitious material

5. Characterization of Ash
 Following are the some of the characteristics of the wood ash
 Water content
 To find water content, three samples were weighed out and dried
at for 24 hours, and weighed again. From this water content can
be found.
 water solubility
 When using ash as a cement replacement, it is important to know
how much ash is added. This can be difficult if a part of the ash is
water soluble, as this part will be dissolved in water during
casting. Therefore the solubility of the ash is found.
 Particle size distribution
 For the ash to work well as a cement replacement, it is best, that it
has roughly the same particle size distribution as cement

6. Properties Wood ash
 Physical properties of wood ash
 Wood ash is heterogeneous mixture of different sized
particles generally angular in shape.
 Wood ash basically contains some burned or unburned wood
and bark.
 To evaluate fineness, average amount of wood ash retained
on sieve is 50%.
 Specific gravity of wood ash is 2.56 and fineness is 6%
while as for cement it is 3.15 and fineness up to 10%.
 pH of wood ash is 10.48 while as for cement it is 12-13.

7. Chemical Properties of Wood Ash
S. No. Composition (Mass %) Wood ash cement
1 Silica (Sio2) 31 21.25
2 Alumina (Al2O3) 14.40 5
3 Iron oxide (Fe2O3) 6.90 1.85
4 Lime (CaO) 12.60 65
5 Magnesium oxide (MgO) 0.69 2
6 Potassium oxide (K2O) 1.57 0.71
7 Sulphur trioxide (SO3) 0.89 3.70
8 Loss on ignition(1000⸰C) 34.30 3
9 Moisture content 1.60 -
Comparison of Composition Of Binding Material

8. Advantages
 Wood ash in the concrete mix efficiently replaces Portland
cement that in turn can aid in making big saving in
concrete material prices.
 It is also an environmental-friendly solution, which meets
the performance specifications. it effectively combines
with alkalis from cement, which thereby prevents the
destructive expansion.
 Wood ash act as pozzolana in concrete.
 Eliminate or reducing the waste
 Reducing the cost of cement

9. Disadvantages
 The quality of wood ash used should be very vital. Poor
quality often has a negative impact on the concrete.
 The poor quality can increase the permeability and
thus damage the building

10. Issues with OPC
 Conventional Portland Cement is the most consumed
commodity in the world after water.
 It is also the most energy intensive material
 Cement production leads to high carbon-dioxide emission.
 A reduction in the CO2 emitted by the building industry could
come from using less cement, and instead replacing it with
other materials, like bio ash, wood ash that at the moment is a
waste product.
 CO2 is the primary green house gas that causes global warming
 Manufacturing of cement accounts for 6 to 7% of the CO2 that
humans produce.
 It is produced by calcination of limestone and burning of fossil
fuels

11. Objectives
 To study the effect on compressive strength of concrete
with the wood ash as partial replacement for cement.
 To study the effect on worakability of concrete.

12. Methodology
LITERATURE REVIEW
DETERMINATION OF OPTIMUM PERCENTAGE OF
REPLACEMENT FOR CONCRETE
COLLECTION OFMATERIALS
MATERIAL TESTING
MIX DESIGN
CASTING OF SPECIMEN
RESULT AND OBSERVATION
Testing of specimen

13. Materials Used
 Binding material
 Ordinary Portland cement
 Wood waste ash
 Powdery, amorphous solid, sourced locally from baker’s oven.
 Fine aggregates
 Sand
 Coarse aggregates
 Crushed angular shaped aggregates: 10mm and 20mm
 Water
 Water free from impurities and portable (fit for drinking)

14.  Aggregates
Material Test Results
Materials Zone Specific
gravity
Water
absorption (%)
Fineness
modulus
Fine
aggregates
ii 2.5 1.08 2.23
Coarse
aggregates
2.67 0.4 7.14

15. Material Test Results
 Binding material
 Cement and wood ash
 Specific gravity of wood ash is low as compared to cement.
Material property Cement Wood ash
Specific gravity 3.0 2.65
Fineness 2.3% 6%

16. Details of Concrete Mix
 Type of concrete: OPC 43 Grade
 Nominal size of aggregates: 10-20mm(40% and 60%
respectively)
 Maximum cement content: 452.57kg/m3
 Max water cement ratio: 0.45
 Workability: 75 mm slump
 Type of coarse aggregates: Crushed
 Zone of fine aggregates: (ii) zone

17. Details of Mix Design
S. No Mix
designation
Quantity in kg for one cubic meter of concrete
Binding material Coarse
aggregates
Fine
aggregates
water
Cement Wood
ash
20mm 10mm
1. JQ-0% 438 - 637 424.8 657 197
2 JQ-10% 394.2 43.8 637 424.8 657 197
3 JQ-20% 350.4 87.6 637 424.8 657 197
4 JQ-30% 306.6 131.4 637 424.8 657 197
Grade of mix :M-30 (1:1.5:2.4) Target mean strength:38.2 N/mm3

18. Results and Discussions
 Test on fresh concrete
 The workability of concrete decreases with the increase in
wood ash content in concrete.
S no. Mix designation Slump
1 JQ-0% 75
2 JQ-10% 5
3 JQ-20% 0
4 JQ-30% 0

19. Result And Discussion
• Test on hardened concrete
• Cube compressive strength
Mix designation Compressive strength
(7 days )N/mm2
Compressive strength
(28 day) n/mm2
JQ-0% 20 35.8
JQ-10% 19.49 31.48
JQ-20% 17.92 23.89
JQ-30% 11.56 15.65

20. Result And Discussion
0
5
10
15
20
25
30
35
40
0% 10% 20% 30%
CompressiveStrength(N/mm2)
% Replacement of Wood Ash
7 Days
28 Days

21. Result And Discussion
0
5
10
15
20
25
30
35
40
0% 10% 20% 30%
CompressivestrengthN/mm2
Design mix of m-30 concrete mix
7 days
28 days

22. Conclusion
 The increase in addition of wood ash decreased the
compressive strength at all ages. This is mainly attributed to the
water demand required by wood ash.
 The decrease in compressive strength for 10% to the reference
concrete is marginal but for other mixes the strength variation
is very significant.
 The water requirement increases as wood ash content increase
 During the testing it was observed that there was an increase in
the ductile behaviour of concrete for wood ash replacement
when tested under CTM. The time required to break the wood
ash specimen was long enough as compared to break the
control specimen, as the development of cracks started
increasing slowly under same rate of loading.

23. THANK YOU