1

Title Author Year Objective Methodology Outcome/finding/conclusion Future research

1. COAL

COMBUSTIO

N BOTTOM

ASH AS

MICROFILLE

R WITH

POZZOLANIC

PROPERTIES

FOR

TRADITIONA

L CONCRETE

Diana

Bajare

2013 find out the economic

benefit and efficiency

for the partial

replacement of

cement with coal

combustion bottom

ash (CCBA) as well

as if it is possible to

use CCBA as

microfiller like flay

ash with pozzolanic

properties in

production of

concrete

1. CCBA was grinded in

planetary ball mill Retch® PM

400 for 4, 15, 30 and 45

minutes. Various grinding

periods were applied in order

to find out how the

granulometric composition will

impact properties of concrete

and if the grinding period has

an impact on the CCBA

pozzolanic activity. 20% and

40% of cement mass in the

concrete mix was replaced by

the grinded CCBA.

1. The grinded CCBA can effectively replace

cement up to 20% of its total amount without

reducing compressive strength of concrete and its

strength class. By replacing 20% of cement with

CCBA compressive strength class of concrete

C30/37 can be ensured, which is equivalent to the

reference mix of concrete.

2. Comparing concrete where 20% of cement is

replaced with CCBA with the one where 20% of

cement is replaced bydolomite flour, the formed

showed higher compressive strength (by 7–12%),

as well as higher depth of penetration of water and

water absorption rate, indicating that dolomite

flour is more useful as microfiller from the filler

packing point of view.

3. Replacing 40% of cement with CCBA

2

2. In order to determine the

efficiency of CCBA and its

impact on the concrete

structure and its mechanical

properties, several etalon or

reference concrete mixes were

prepared:

1) Mixes without replacing of

cement and 2) mixes where

cement is partially replaced by

inert filler – dolomite flour – in

the same proportions as CCBA

– 20 and 40% respectively. By

comparing the mechanical

properties of reference mix

(with 100% of cement) to the

mix with CCBA (20% and

40% of cement mass) it is

possible to evaluate the CCBA

(regardless of its grinding period) the compressive

strength of concrete reduces significantly. After 28

days of curing compressive strength class of

concrete reduces to C20/25 compared to the

compressive strength class C30/37 for the

reference mix of concrete. Strength indicators are

even lower for the concrete with inert fillers

(dolomite flour) reaching class C16/20.

4. The research results approve that CCBA has

little pozzolanic activity, because comparing

concrete specimens with the equivalent amount of

CCBA (CCP4/20 – 45 MPa) and dolomite flour

(D20 – 40 MPa), properties of the latter are

higher. In addition, this tendency do not change if

amount of fine particles in CCBA increases. It was

approved in the chemical composition research,

which showed that pozzolanic activity of CCBA

increases only slightly if the specific surface area

3

activity and its role in the

concrete strength increase as a

result of long term

curing, By analysing results

obtained from research of

CCBA containing concrete and

concrete with inert filler in

their

turn, it is possible to determine

the role of the CCBA

microfiller in ensuring ideal

filler packing and creation of

dense concrete structure.

3. properties of CCBA were

determined, such as substance

density by Le Chatelier flask,

particle size distribution after

different grinding periods (4,

of particles expands.

5. After 28 days of curing compressive strength

class of concrete with CCBA grinding period of 4

minutes reaches C16/20 and with CCBA grinding

period of 15 minutes reaches C20/25.

Compressive strength of concrete differs by

14.8%. The respective compressive strength

increase do not provide corresponding economic

benefit for additional grinding period (+11 min),

therefore energy and resources can be economized

on the grinding. Partially replacing cement with

the CCBA, the consumption of cement and CO2

emission from the cement production reduces

significantly. In addition to cement economizing,

possibility of environmental pollution with CCBA

is prevented and effective application for CCBA is

found.

4

15, 30 and 45 minutes) (LVS

EN 933-2:1995 un LVS EN

451-2:2001),

CCBA particles were

investigated under scanning

electron microscope (SEM

TESCAN Mira\LMU

Field-Emission-Gun)

and chemical composition was

determined with EDX (energy

dispersive X-ray spectrometry

– EDS, Oxford instruments

7378). The specific surface

area of particles was

deteremined by Porosimeter

NOVA 1200Е (0.35– 200 nm)

“Quantachrome Instruments”.

The pozzolanic activity of

particles was determined

5

according to the method

created at the

Laboratory of Analytical

Chemistry, Short description of

method:

Fine grinded materials

containing active SiO2 and

Al2O3 (pozzolanic additives or

hydraulic components) are

dissolved in weak hydrochloric

acid. Silica and aluminium

hydroxide are separated from

the solution by determining

their weight fractions followed

by burning of precipitates in

order to obtain active SiO2 and

Al2O3.

4. Cone slump of fresh mortar

6

specimens was determined

according to LVS EN

12350-2:2009. The necessary

amount of water for mortar

preparation was determined

experimentally depending on

the composition of mortar

aiming to maintain class S4

cone slump, which is 160 –

210 mm.

Mortar bulk density was

determined according to LVS

EN 1015-6:2003.

5. Density of hardened

concrete for concrete

specimens was determined

according to standard LVS EN

12390-7.

7

Compressive strength of

specimens was determined

according to standard LVS EN

12390-3/AC. Loading rate was

0.7 MPa/s.

Compressive strength of

specimens was determined

using hydraulic press

CONTROLS 3000kN.

Compressive strength of

concrete was tested for 7, 14,

28 and 90 days old specimens.

Depth of penetration of water

under pressure for concrete

was determined according to

standard LVS EN

12390-8:2009 with the

8

Controls impermeability

apparatus C245 by exposing

one surface of specimens to the

water with pressure of 5

atmospheres.

This experiment continued 72

hours. Water absorption was

determined for 28 days old

concrete specimens.

6. Chemical composition of

visually different CCBA

particles was detected using

EDX

7. Three different reference

mixes were prepared in order

to compare their properties

with those of CCBA containing

9

concrete. In one of the

reference mixes 100% of

cement was used as binder and

in two mixes cement was

partially replaced

by inert filler – dolomite flour

– 20 and 40% from the cement

mass respectively.

8. Four different mixes with

CCBA were prepared – two of

them with CCBA grinded for 4

minutes and other two with

CCBA grinded for 15 minutes,

replacing with it 20 and 40%

from the cement mass.

9. Normal curing regime was

applied to specimens

10

(10x10x10 cm) – demoulded

specimens were kept in the

water with temperature

20±2 °C for 3 days, then

placed in the room with

constant temperature regime

(20±2 °C) and humidity level

(relative humidity 95% ).

Specimens were kept there

until the tests and experiments.

Mortar bulk density for all

specimens ranged from 2358 to

2382 kg/m3

2. USAGE OF

COAL

COMBUSTIO

N BOTTOM

ASH IN

CONCRETE

Haldu

n

Kuram

a

2007 The purpose of the

present study is to

test common methods

(such as sink and

float test, particle size

classification, and

1. In this study, the total carbon

content of generated ash was

determined by employing the

standard loss-on-ignition

analysis (LOI) and the

determined LOI is accepted as

main conclusions can be drawn;

1. Compared to other pre-treatment methods such

as the heavy medium separation and electrostatic

separation methods, the crushing-screening

method was found to be a more useful route for

lowering the carbon content of the considered

11

MIXTURE electrostatic

separation) as an

effective and

economical method

for removing of

unburned carbon

from Tunc¸bilek

Power Station bottom

ash in order to

enhance its

application as a

constituent in

concrete production.

2. The paper also

examines the effects

of pre-treated CBA

additions on the final

concrete properties as

the mass of unburned carbon in

the original sample, which is a

common approach in cement

and concrete applications. size

values were calculated as 2.7

and 1 mm, respectively.

2. The specific gravity of the

sample measured by the

pycnometer method was 2.39

g/cm3.

3. The crystalline mineral

phases in the CBA were

identified by using X-Ray

Diffraction (XRD), model

S5000 diffractometer, with a

nickel filtered Cu Ka.

CBA. By using this method, 57.67% of feed CBA

was beneficiated with an unburned carbon content

of 4.65%.

2. In concrete tests, although the compressive and

flexural strengths of specimens cured at 56 day

increase with increasing amount of ash

replacement up to 15%, the maximum substitution

rate of CBA was determined as 10%. When 10%

of CBA is replaced by cement, the compressive

strength of CBA-concrete increases from 42.65

N/mm2 to 45.1 N/mm2. This relatively lower

substitution ratio compared to the common

practice of fly ash usage, can be attributed to the

different phase distributions and higher unburned

carbon contents of CBA.

3. The observed C–S–H fibres or elongated

particles on the

SEM micrograph of BC10 clearly indicate the

12

a replacement

for Portland cement

in cement mixture

4. The scanning electron

micrograph of ash shows

spherical, rounded and

irregularly shaped grains.

Methods

1. Pre-treatment

Particle size separation.

Mechanical means of removing

carbon from siliceous ash is

based on the relative particle

size of the carbon particles and

the siliceous particles in the

ash. In this study, the

representative 500 g of CBA

was subjected to laboratory

impact crusher with and

without using 2 mm separating

sieve.

pozzolanic

effect of CBA substitution on improving the

strength

13

2. Sink and float tests. The sink

and float tests were performed

on crushed samples at various

densities to assess the

suitability of heavy medium

separation. These experiments

were conducted in 250 mL

glass flax with a volume of 100

mL, using an appropriate

mixture of bromoform and

alcohol to adjust the density of

liquid between 1.0– 2.4 g/cm3.

A 50 g of representative ash

sample was introduced in the

liquid of highest density. The

floating product was removed,

washed and then placed into

the next lower density and so

on.

14

3. Electrostatic separation tests.

Electrostatic separation

encompasses a number of

different technologies which

are based on the electrical

properties of the particles to be

separated. The electrostatic

separation tests were carried

out by using a

conductor/non-conductor type

of separator (Boxmag Rapid

Ltd-HT150).

4. Moulding of CBA paste

specimens Representative

cement compositions were

prepared by progressive

incorporation of pre-treated

samples in place of Portland

15

cement (5, 10, 15, and 25 wt%)

to observe the effect of ash

addition in cement bodies.

5. The physical tests of

the cement mixes were

performed according to

Turkish standards TS EN

197–1. The cement–water

mixtures were stirred at a low

speed for 30 s, and then with

the addition of sand, the

mixture was stirred again for 5

min. Three 40x 40 x160 mm

prismatic specimens for

compression tests were

prepared from each mixture.

The moulded specimens were

16

cured at 20 C with 95%

humidity for 24 h, and then

after placed in a tap water and

cured for 7, 28 and 56

days.

3.

POZZOLANIC

PROPERTIES

OF

PULVERIZED

COAL

COMBUSTIO

N BOTTOM

ASH

M.

Cheria

fa

1999 This paper examines

the pozzolanic

activity of a Brazilian

bottom ash and a way

that allows for an

improvement of its

reactivity.

1. Characterization of the

bottom ash

The chemical composition of

the bottom ash is given in

Table 1. The calcium content is

very low (,1%) and the sum

(SiO2b + Al2 O3 + Fe2O3)

reaches 88.5%, which means

that this ash belongs to ASTM

Type F ash.

For this bottom ash, the loss on

ignition (LOI) is mainly due to

Conclusion

1. This particular ash, very poor in CaO (0.8%),

presents a certain similarity to class F fly ash.

2. The pozzolanic activity of bottom ash with lime

is very low till 14 days of hydration. Pozzolanic

activity starts at 28 days and the calcium

hydroxide consumption is very important at 90

days.

3. The strength activity indexes with Portland

cement determined on standard mortars according

to the European standard ENV450 reach 0.88 at

17

carbon The X-ray

diffractogram of the ash .shows

the presence of a glassy phase

with two major crystalline

phases of quartz and mullite.

This low-calcium ash shows

diffused halo maxima at 20–27

82 u (Cu Ka radiation).

The scanning electron

micrograph of the ash, shows

both spherical and rounded

particles, and irregularly

shaped grains.

The specific gravity measured

by the pycnometer method was

2.0.

28 days and 0.97 at 90 days. Such values allow the

use of bottom ash in concrete.

4. An adequate grinding improves the pozzolanic

activity of the bottom ash. The filling role of

ground ash is also interesting and the 28-day

strength index of ash is increased by 27% when it

is ground for 6 h in laboratory ball mill.

18

The particle size distribution of

bottom ash as received was

measured using a laser

granulometer.

Of the particles, 100% were

smaller than 100 mm and 2%

were smaller than 1mm. The

average diameter of the particle

size distribution was 35 mm.

Evaluation of the pozzolanic

activity of ash and other

pozzolans falls into three

categories: chemical, physical,

and mechanical.

The chemical evaluation,

which is the method of the

International Organization for

19

Standards (ISO)

recommendation R 863-1968,

measures the reduction of

calcium ions when a pozzolan

is suspended in a saturated

lime solution.

The X-ray diffraction

technique has been used to

monitor the progress of the

lime up take in pozzolan-

Portland cement containing fly

ash and rice-husk ash [10].

The results obtained by this

method indicated good

correlation between the lime

combined in the reaction and

the compressive strength of

20

mortars at 6 months and 1 year.

The mechanical methods

assess the strength properties

of concretes containing fly ash

and pozzolans, and ASTM C

311 describes the strength

activity with Portland cement

and with lime. For both, the

compressive strength of the

control mixture is compared

with the strength of

pozzolan-containing mixture at

ages of 7 or 28 days.

In the present study, both

mechanical and chemical

assessments of the pozzolanic

21

activity with lime were

performed.

Plain paste containing 50%

bottom ash (BA) and 50%

calcium hydroxide (CH) was

prepared at standard

consistency.

The water-to-solid ratio was

0.42. The paste was placed into

cylinders (Ø =50 mm, h=100

mm), kept in molds for 6 days,

then cured in water until 13,

27, and 89 days of hydration.

Before testing the samples

were dried at 50C for 1 day.

22

The cylinders were subjected

to compressive strength tests at

7, 14, 28, and 90 days.

At the same ages, the calcium

hydroxide consumption was

measured by the following

method, previously developed

by Ambroise et al [11]

to study the pozzolanic activity

of metakaolin. The

measurement was done by

differential thermal analysis on

600 mg of powder ground to be

smaller than 100mm. The

surface area of the residual

calcium hydroxide peak was

measured and compared to that

23

of a paste containing 50%

calcium hydroxide and 50%

ground silica, which acts as an

inert material.

The ratio between these two

peaks gave the relative calcium

hydroxide consumption of

bottom ash compared to an

inert filler. The microstructure

of the different pastes was also

investigated by scanning

electron microscopy associated

with energy- dispersive X-ray

analysis, using a Philips XL30

microscope (Philips, The

Netherlands). Strength activity

of bottom ash The strength

activity of bottom ash was

24

determined according to the

European standard EN 450.

The strength activity

index is the ratio of the

compressive strength of

standard mortar bars, prepared

with 75% reference cement

plus 25% ash by mass, to the

compressive strength of

standard mortar bars prepared

with reference cement alone,

when tested at the same age. If

these indexes are higher than

0.75 at 28 days and 0.85 at 90

days, the ash is allowed to be

used in concrete.

4.

LIGHTWEIG

A.

Beglar

2015 1. In this

experimental

1. Materials used in this

study are ordinary Portland

CONCLUSIONS

25

HT

BUILDING

BLOCKS

INCORPORAT

ING BOTTOM

ASH

AGGREGATE

UNDER

DIFFERENT

CURING

CONDITIONS

igale research, utilization

of bottom ash of

Dalan Chemical

Company and fly ash

of Soma B power

plant (placed in

Turkey), as a

construction material,

were investigated.

Test results showed

that, high volume

bottom ash and fly

ash can be used in the

production of

lightweight building

blocks as light weight

aggregate and binder,

respectively.

cement (CEM I 42.5 N), fly

ash (FA) of Soma B plant

and bottom ash of Turkey’s

Dalan Chemical Company.

According to ASTM C 618,

FA can be classified as class

C.

2. Bottom ash and pumice

were used as aggregate (0-5

mm).

3. In the first stage, the

effect of bottom ash

aggregate replacement on

mechanical properties was

investigated in three

different curing conditions

(28-day water curing, steam

Applying the bottom ash (BA) and the fly ash in

the production of lightweight building blocks were

investigated in this study. Pumice aggregate was

replaced by bottom ash in high volume. Fly ash

was also replaced with cement in high volume.

Test results indicated that;

- BA replacement level must be limited due to

dimensional stability problem which was observed

especially over 50% of BA replacement ratios in

standard water curing.

- There is no significant difference in compressive

strength of 50% BA containing and 100% pumice

containing mixtures. Furthermore, autoclave

curing is the most effective curing method among

the others from the point of early and ultimate

compressive strength development.

26

curing, and autoclave

curing).

4. Five different mixtures

were prepared. These

mixtures are BA0, BA25,

BA50, BA75 and BA100,

which indicates bottom ash

replacement level by weight.

5. In the second stage,

selected bottom ash mixture

(BA) and control pumice

mixture (P) were prepared.

6. The mixtures were

prepared in a Hobart mixer.

Test specimens were cast

- Porosity of BA mixture is slightly higher than

pumice mixture. Both dry bulk density and

specific gravity of BA mixture are lower than P

mixture due to lower unit of weight and porous

structure of bottom ash. Therefore, BA mixture is

suitable to produce lightweight elements.

- Thermal conductivity value of BA mixture is

lower than P mixture. The results of both mixtures

are lower than the conventional cement mortar

and in turn comparable with burn clay bricks.

- Porous structure of P and BA particles which

was observed in microstructural investigation

leads to an increase in the porosity of mixtures.

- Compressive strength of building blocks

produced from BA mix is approximately 25 % less

than P one. However, utilization of bottom ash

27

from the same batch into

steel molds. Physical and

mechanical properties were

determined after different

curing regimes.

7. After the curing period,

three cube specimens (50

mm x 50 mm 50 mm) from

each mixture were subjected

to compressive strength test.

8. Physical properties of

specimens were also

determined. Prismatic

specimens (40 mm x 40 mm

x 160 mm) were used in

thermal conductivity and

capillary suction tests.

(BA) and fly ash are definitely suitable for the

production of lightweight building blocks.

These mixtures are very environment-friendly due

to the utilization of solid wastes in high volume

and lack of burn process compared to the clay

bricks.

28

Bottom surface of the

prismatic specimens up to a

height of 3–4 mm is in

contact with water inside a

steel tray

9. Specimens were removed

from the steel tray at the

intervals of 4, 8, 12, 16, 20,

and 24 min and weighed

carefully .Furthermore, in

order to determine the

volume stability of mixtures,

prismatic (width: 25 mm,

height: 25 mm, length: 285

mm) specimens were used.

Building blocks and hallow

blocks were prepared by

29

using the selected mixtures.

5.

POTENTIAL

USE OF

MALAYSIAN

THERMAL

POWER

PLANTS

COAL

BOTTOM

ASH IN

CONSTRUCTI

ON

Abdul

hamee

d

2012 1. a critical review

of the strength

characteristics of

concrete and mortar

as influenced by CBA

as partial replacement

of fine aggregate is

presented based on

the available

information in the

published literatures.

2. Diverse physical

and chemical

properties of CBA

from different power

plants in Malaysia are

also presented.

1. Physical properties.

Bottom ash is sand sized,

usually 50-90% passing

a4.75mm (No. 4) sieve. It also

has 10 - 60% passing a

0.42mm (No. 40) sieve, 0 -

10% passing a 0.075mm (No.

200) sieve, and a top size

usually above 19mm.

For categorization given in BS

882: 1992 based on percentage

passing the 600μm sieve,

between 55% to 100% would

defined it as fine sand.

The grading requirements for

ADVANTAGES OF USING COAL BOTTOM

ASH.

1. It is possible to produce lightweight concrete

with a density in the range of 1560-

1960 kg/m3 and a 28 day compressive strength in

the range of 20-40 N/mm2 [30]. Though, the

strength development is slow at the beginning but

with extended curing days, maximum strength can

be achieved.

2. Bottom ash may be used as a partial

replacement of natural aggregates, with finer

bottom ash used as sand. The percentage of

bottom ash that can be used in a mixture

composition depends upon its quality and required

strength of the product [34].

Future research on the use

of coal bottom ash in

construction should focus

on the following:

1. An established set of

standards that spells out

guidelines on its usage

and regulates it if need be.

2. Long-term study on the

effect of durability and

strength properties of

concrete and mortar using

coal bottom ash is

required.

30

3. The influence

of different types,

amounts and sources

of CBA on the

strength and bulk

density of concrete

is discussed.

4. The setting time,

workability and

consistency as well as

the advantages and

disadvantages of

using CBA in

construction

materials are also

highlighted.

fine aggregates has been

described into four zones in BS

882: 1973 and it was done

based on the percentage

passing the 600μm (No. 30

ASTM) sieve.

2. Specific gravity of bottom

ash is a function of chemical

composition, with higher

carbon content resulting in

lower specific gravity.

Coal Bottom ash with a low

specific gravity, has a porous

or vesicular texture, a

characteristics of popcorn

particles that readily degrade

under loading or compaction

[13].

3. Inclusion of bottom ash has a more pronounced

influence on tensile resistance than on

compressive strength, reduction of splitting tensile

strength is hardly noticed, as long as a minimum

cement content of 365 kg/m3 is utilized [28].

4. Drying shrinkage decreased with an increase in

bottom ash content. Concrete made from bottom

ash exhibits a reduced drying shrinkage in

comparison with that of the control samples [28].

5. Due to increased demand for mixing water,

bottom ash mixture displayed a much higher

degree of bleeding than the control concrete [28].

6. High fire resistance: for protection against fire,

those materials that retain large quantity of water

are more desirable, since when they are exposed

to a fire, part of this water evaporates and is

3. The influence of

constituent materials on

the water absorption [19].

4. Chloride transport and

Corrosion effect of coal

bottom ash concrete.

31

5. An effective

utilization of CBA in

construction

materials will

significantly reduce

the accumulation of

the by-products in

landfills and thus

reduce environmental

pollution.

Bottom ash with a porous or

hollow ash may present a

specific gravity as low as or

even lower than 1.6 [14].

The range of the specific

gravity of this bottom ash

might be different depending

on coal type, origin, size,

handling, processing technique,

boiler size, disposal and

storage methods or other

criteria [15].

All these factors mentioned

have a commanding influence

on the specific gravity property

of bottom ash, as reported by

[16],

transported from the fire exposed surface to the

interior of the material, where the water cools and

condenses again [35].

7. Fly and bottom ashes increase the fire

resistance of blocks, and are principally due to the

wide evaporation plateau that those ashes incur as

a result of increase water intake of the porous

aggregates [21]

DISADVANTAGES OF USING COAL

BOTTOM ASH.

1. The early strength development of coal bottom

ash has been shown to be very slow at the

beginning, but as the curing period is extended

beyond 28 days, a dramatic increase in strength is

noticed [6].

32

When they investigated the

physical properties of bottom

ash specimen taken from

different disposal points in a

disposal pond. “There is a

difference of Gs between the

sample taken from nearest to

slurry disposal point and one

taken farther away”

3. CHEMICAL PROPERTIES

The chemical analysis of CBA

either using X-ray energy

dispersive spectrometry (EDS)

or X-ray fluorescence (XRF)

will reveal that the main

chemical compounds include

2. Bottom ash mixtures display a lower modulus

of elasticity than the control mixes. The empirical

relationship between static modulus of elasticity,

unit weight and compressive strength is slightly

lower than that suggested by the American

Concrete Institute (a=31.2) [28].

3. Due to high water absorption rate, angular

shape and very porous surface of the bottom ash,

higher water content is required to achieve the

degree of lubrication needed for a workable mix.

The increase water demand has a moderate effect

on early-age characteristics of bottom ash

concretes [28].

4. The inclusion of bottom ash has been shown to

delay the setting time of the mixture with increase

in percentage of bottom ash, the initial setting

time is further delayed. This can be attributed to

33

Silicates (SiO3), Aluminates

(Al2O3) & Iron oxide (Fe2O3)

with a host of other compounds

in smaller percentages.

4. INFLUENCE OF COAL

BOTTOM ASH ON THE

MECHANICAL

PROPERTIES OF

CONCRETE & MORTAR.

According to [6],

“Bottom ash has a large

particle size and a high porous

surface, resulting in higher

water requirement and lower

compressive strength”. The

water retention capacity of

bottom ash has also

the reduction in the quantity of C3S as a result of

adding bottom ash and the amount of mixing

water required to maintain a workable mix.

34

been highlighted by [21] &

[22] that “additions increase

the capacity of aerated block to

retain water since Bottom ash

is a porous material, thereby

improving the moisture

transport behavior

within the block during fire”

Method Standard Onjective Type of

sample

Day testing No of

sample/

cubes/slabs

35