REPLACEMENT OF CEMENT WITH FLYASH

1. ANNAMACHARYA INSTITUTE OF TECHNOLOGY AND SCIENCES
CIVIL ENGINEERING
MINI PROJECT WORK
UNDER GUIDENCE OF
S.Hanmanthu (ASST.PROFF)
PROJECT ASSOCIATES:
B.Nithya sri 21T85A0117
D.Vandana 21T85A0139
V.Anil 21T85A0106
M.Ramesh goud 21T85A0120
G.Saikiran 20T81A0107
REPLACEMENT OF M30 GRADE CEMENT WITH FLY ASH

2. The concept of partial replacement of cement which is capable for sustainable
development is characterized by application of industrial wastes to reduce consumption
of natural resources and energy and pollution of the environment. Presently large
amounts of fly ash are generated in thermal industries with an important impact on
environment and humans. This research of cement describes the feasibility of using the
thermal industry waste in concrete production as partial replacement of cement. Fly ash
and silica fume can be used as filler and helps to reduce the total voids content in
concrete. The cement has been replaced the total ash accordingly in the range of 10%,
20%, 30%, by weight of cement and 10% of silica fume in common for M-30 Mix.
Nowadays due to rapid growth in construction cement is very costly.
Key words: Green concrete, compressive strength, split, tensile strength, fly ash, silica
fume.
ABSTRACT

3. A various numbers of research have been conducted to examine the effects of use of Fly Ash as additive in
cement, admixture in concrete and as replacement of cement in concrete. The compressive strength of concrete
was checked by replacing different proportions of cement with suitable quantities of Fly Ash and the results have
been found most effective and applicable. Incidentally most of the research works have been conducted only for a
limited percentage of cement replacement that too for a lower grade of concrete. It is therefore necessary to
conduct an extensive research on compressive strength of different qualities of concrete as well as different
proportions of Fly Ash at different curing periods. Herein below the various methods of using the Fly Ash as a
cement replacement in concrete is discussed vividly.
INTRODUCTION

4. Concrete:
 Concrete plays a significant role in the construction of structure around the world. According to
construction materials (2007) concrete is a composite material obtained by mixing cement, sand, gravel
and water. A concrete mix can be considered to consist of two main parts, aggregates(sand and gravel)
and cement paste (water and cement).
 The global demand of concrete is significantly increasing due to infrastructure growth worldwide.
Therefore using alternative sources as replacement for cement and aggregates appears to be a
challenging task.
 There are many potential industrial waste products that have the potential to replace aggregates in
concrete such as: plastic, fly ash, rubber, steel slags and leather wastes. However, fly ash is the
industrial waste material that is discussed in depth in this particular research.

5. Arivazhagan (2011)
conducted a peculiar study on the environmental benefit with fly-ash stated that
there is increases in crop yields and nutrient uptake due to release of major
secondary and micro nutrients from flyash applied in the soil during crop growth.
Basically fly-ash has slightly acidic in pH and its effect is more pronounced in soils
having high pH.
Jayesh kumar Pitroda (2012)
It is shown in this paper that this research work describes the feasibility of using
the thermal industry waste in concrete production as partial replacement of cement.
The use of fly-ash in concrete formulations as a supplementary cementitious material
was tested as an alternative to traditional concrete. The cement has been replaced
by fly-ash accordingly in the range of 0% (without fly ash), 10%, 20%, 30% & 40% by
weight of cement for M-25 and M-40 mix. Concrete mixtures were produced, tested
and compared in terms of compressive and split strength with the conventional
concrete.
LITERATURE REVIEW

6. Swaroop (2013)
In his presentation the study is mainly confined to evaluation of changesin both compressive strength
and weight reduced in five different mixes of M30 Grade namely conventional aggregate concrete (CAC),
concrete made by replacing 20% of Cement by fly-ash (FAC1), concrete made by replacing 40% of
cement by fly ash(FAC2), concrete made by replacing 20% replacement of cement by GGBS (GAC1) and
concrete made by replacing 40% replacement of cement by (GAC2). The effect of 1% H2SO4 and sea
water of those concrete mixes are determined by immersing these cubes for 7 days, 28 days, 60 days in
above solutions and the respective changes in both compressive strength and weight reduction had
observed and upto a major extent we can conclude concretes made by that flyash and GGBS had good
strength and durable properties comparison to conventional aggregate in severe environment.

7. P. Nath and P. Sarker
The research work included replacement of cement with fly ash by 30-40%, which resulted in compressive
strength of 60 MPa after 28 days and 85 MPa after 56 days of curing. The strength for 30% replacement was more
than that of 40% replacement. The researchers also tested the chloride ion permeability and found out that it
reduced by 35 – 45% and more after 28 days. Fly ash reduced the drying shrinkage as well as the sorptivity of the
concrete.
Harison et al (2014)
Conducted a peculiar study on the utilization of materials which can fulfill the expectations of the construction
industry in different areas. In this study cement has been replaced by flyash accordingly in the range of
0%,10%,20%,30%,40%,50%,60%by weight of cement for M-25 mix with 0.46 water cement ratio. Concrete
mixtures were produced, tested and compared in terms of compressive strength. It was observed that 20% of
replacement of Portland pozzolana cement (PPC) by fly-ash strength is increased marginally (1.9% to 3.2%) at 28
days and 56 days respectively.

8. Scope
The purpose of this research is to determine the feasibility os using fly ash as a replacement of cement and fine aggregate in
concrete. Using a product such as fly ash in concrete can influence the mechanical properties of concrete. The original scope of
this study is to investigate the fresh and hardened properties of concrete with fly ash as a replacement of cement and fine
aggregate.
Aim
In order to achieve the scope of this research, the following objectives have to be met:
 Research background information on the basic materials of fly ash, cement and fine aggregate
 Research the chemical and physical properties of fly ash, cement, and fine aggregate(sand), and determine the feasibility of
replacing cement and sand with fly ash.
 Research the effects of combining fly ash into the concrete mixture.
 Concrete mixtures with different percentages of fly ash were prepared to be tested.
 A comprehensive laboratory study was performed to study the mechanical properties of concrete mixtures with different ratios
of fly ash as a replacement of either cement or fine aggregate.

9. Fly ash
Nature of fly ash and its production:
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. Over 61 million metric tons (68 million tons) of fly ash were produced in 2001.
Fly ash is produced by coal-fired electric and steam generating plants. Typically, coal is pulverized and blown with air
into the boiler's combustion chamber where it immediately ignites, generating heat and producing a molten mineral
residue. Boiler tubes extract heat from the boiler, cooling the flue gas and causing the molten mineral residue to
harden and form ash. Coarse ash particles, referred to as bottom ash or slag, fall to the bottom of the combustion
chamber, while the lighter fine ash particles, termed fly ash, remain suspended in the flue gas.
Production:
Fly ashes produced by FBC boilers are not considered in this document. Fly ash is captured from the flue gases
using electrostatic precipitators (ESP) or in filter fabric collectors, commonly referred to as baghouses. The physical
and chemical characteristics of fly ash vary among combustion methods, coal source, and particle shape.

10. Advantages:
Fly ash is most commonly used as a pozzolan in PCC applications. Pozzolans are siliceous or
siliceous and aluminous materials, which in a finely divided form and in the presence of water, react
with calcium hydroxide at ordinary temperatures to produce cementitious compounds.
 Used in the manufacture of Portland cement.
 Used as a soil stabilization material.
 Fly ash is also used as a component in the production of flowable fill.
 Fly ash is used as component in geo polymers.
Disadvantages:
 Pulverized fuel ash may affect the colour of concrete. According to ‘A.M. NEVILLE’ colour of fly ash
concrete to its carbon content. Usually ugly looking darker colour helps in identifying fly ash
concrete with compared to lighter colour ordinary concrete, when two are placed side by side.
 Use of fly ash leads to slower strength gain.
 Class C fly ash is sensitive to temperature, hence in the mass concreting or when temperature rises
to about 200℃ or 400℉, it does not give high strength.

11. TO BE CONTINUED……
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