geopolymer related study

1. STUDY OF PROPERTIES OF
GEOPOLYMER ECO BRICKS
Submitted by
SENTHIL KUMAR

2. ABSTRACT
The purpose of the present study is to investigate the behavior of
Fly ash based Geopolymer eco Bricks and its Durability, the size
of the bricks were adopted was 200mm x 200mm x 400mm.
The brick were cast with fly ash to river sand and eco-sand
(silica sand) with the ratio of 1:2.5 by weight.
Sodium fume solution was used as the alkaline activators. The
binder solution consists of NaOH solution in the ratio of 1:2.5

3.  The optimum water/ binder ratio of 0.416 was selected as per
available literature. The water/binder ratio is the ratio of solution
(NaOH and water) to fly ash. Bricks will be casted in this study
under ambient curing.
 The blocks will cast with different types of sand with river sand,
eco-sand (silica sand). The experimental results obtained were
compared with locally available Cement Solid Blocks.

4. INTRODUCTION
GENERAL
 In our country India of total 329 million hectares of land, it is
estimate that 175 million hectares of land is degraded. The extent of
land under agriculture is 143 mha and again 56% of its suffers from
varying degrees of degradation
 The burnt clay bricks industry in India produces over 360 billion
bricks annually with strong admissions adverse impact on soil
erosion and unprocessed
 Another concern of degradation of soil is about the less utilization of
fly ash, which is produced by the Thermal Power Plant (TPP)

5.  Geopolymer has the potential to reduce green house emissions by
80%. Concrete is till now the most popular material for construction
on earth. To act as binder ordinary Portland cement (OPC) is most
widely used with other materials like water and aggregates
 This paper presents the technology of making geopolymer Solid
Blocks using low-calcium (Class F) dry fly ash as its source material
and presents the results of Physical and Durability studies on this
material

6. THEORETICAL BACKGROUND
 Materials
Fly Ash
 In this Geopoly mer blocks, fly ash is obtained from power plant.
Fine Aggregate
River Sand
 In this investigation, the river sand, which were available in Karur river
sand were used in which it belongs Zone III was used as fine aggregates and
the following table 3.3 as per IS: 2386-1968 Part III.

7. Manufactured sand
 In the present investigation, the manufacture sand, which was available near
Coimbatore, which belong zone II was used as fine aggregate and the
following tests were carried out as per IS:2386-1968 Part III.
Eco Sand
 In the present investigation, The Eco sand is a byproduct from cement
industry, for construction purposes this Eco-sand can be a better alternative
to river sand and it can used as fine aggregates.
Coarse Aggregate
 Locally available crushed blue granite stones conforming to graded
aggregate of nominal size 12.5 mm as per IS 383 – 1970 with the specific
gravity of 2.77.

8. BRICKS
 A moulded rectangular block of clay baked by the sun or in a kiln
until hard and used as building and paving materials (or) a brick is a
block or a single unit of a ceramic material used in masonry
construction.
 They have been regarded as one of the longest lasting and strongest
building materials used throughout history
 In a less clinical and more colloquial sense, bricks are made from
dried earth, usually from clay bearing subsoil. In some cases, such as
adobe, the brick is merely dried. More commonly it is fired in a kiln
of some sort to form a true ceramic.

9. TYPES OF BRICKS
SOLID BRICK
 A Clay brick manufactured with less than 25% perforations
by volume, which is in solid rectangular shape.
PERFORATED BRICK
 A clay brick manufactured with vertical perforations to reduce
weight improve insulating properties and reduce capillary attraction
through a wall.

10. FROGGED BRICK
 A clay brick manufactured with 25% perforation by volume.
The term “frog” for the indentation on one bed of the brick of the
brick is a word that often explains the cavity made o the brick.

11. 1.Silica(sand)-50% to 60% by weight
2. Alumina(clay)-20% to 30% by weight
3. Lime -2 to 5% by weight
4. Iron oxide- <7% by weight
5. Magnesia – less than 1% by weight

12. BRICK MANUFACTURING PROCESS
BRICK INDUSTRY
 Indian brick industry with an estimated coal consumption of 15-
20Million tons per year is the third largest consumer of coal in the
country after power plants and steel industry.
 Modern clay bricks are formed in one of these three processes
1.Soft mod method
2.Dry pressed method
3.Extruded method

13. INGREDIENTS OF BRICKS
1.Silica(sand)-50% to 60% by weight
2. Alumina(clay)-20% to 30% by weight
3. Lime -2 to 5% by weight
4. Iron oxide- <7% by weight
5. Magnesia – less than 1% by weight

14. ECO BRICKS
 Eco bricks are a type of brick, which can be manufacture in
the absence of firing.
 Theses eco bricks are made in a process called microbial-
induced calcite precipitation, or MICP.
 In a chain of chemical reactions, the microbes on sand are
joined together like glue.

15. UREA
 Urea or carbamide is an organic compound with the chemical
formula CO(NH2)2. The molecule has two—NH2 groups
joined by a carbonyl (C=O) functional group.
 Urea serves an important role in the metabolism of nitrogen-
containing compounds by animals and is the main nitrogen-
containing substance in the urine of mammals.
 It is a colourless, odourless solid, highly soluble in water and
practically non-toxic(LD50 IS 15 g/kg.

16. CULRURE OF GROWTH MEDIUM
 A growth medium or culture medium is a liquid or gel
designed to support the growth of micro organisms or cells, or
small plants like the moss .
 Physcomitrella patens. There are different types of media for
growing different types of cells.

17. MATERIALS AND METHODS
Mud
 The soil is taken from the site available at Padur lake in brick
chamber and sieved in 4.65 mm size sieve.
Water
 Locally available portable water confirming to IS 456 is used.
Microorganisms
 Bacillus subtilis- this standard bacterial strain was obtained from
armats biotech laboratory situated in guindy.

18. ISOLATION OF CALCITE
PRECIPITATIONG BACTERIA FOR
MICROBIAL BRICKS
Isolation and cultivation of bacterial species
 The samples were suspended in a sterile saline solution(0.85% NaCl),
serially diluted(fig:3.2) .
 And inoculated by pour technique on precipitation agar containing
urea(20g/1), NaHCO3(2.12g/1), NH4Cl910 g/l), Nutrient broth(3g/l),
CaCl2(25 g/l). PH was maintaioned alkaline in the range of (7.5- 8.0).

19. BIOCHEMICAL TECHNIQUE
Urease test
 Peptone 1.0g/lt
 Sodium chloride 5.0g/lt
 Potassium dihydrogen phosphate 2.0g/lt
 Agar 20.0g/lt
 Distilled water 1000ml

20. CALCULATION OF
GENERATION TIME
 The generation time for the different bacterial isolates was
calculated by direct method, where the nutrient broth was
prepared in a conical flask and sterilized
 The different bacterial isolates were inoculated aseptically
into different conical flask and un-inoculated broth was kept
as control to set the colorimeter to zero.
 At an interval or every 30 mins OD was taken at 760nm till
the OD values doubled.

21. UREASE ASSAY
 The urease activity was determined for all the bacterial
isolates in Urease media by measuring the amount of
ammonia released from urea according to the phenol-
hypochlorite assay method ( Natarajan, 1995), Ammonium
chloride(100ug/ml) was used as the standard.
 One unit of urease is defined as the amount of enzyme
hydrolyzing one moles urea per min.

22.  A loop of microbial cultures were inoculated into calcite precipitation media
(Urea:20g/lt and Calcium chloride:49 g/lt) in separate conical glass of 250ml
.
 And incubated at 370c in an incubator and studied for amount of calcite
precipitation at regular intervals.
2HCl(aq)+CaCo3(s)---Ca2+(aq)+CO2(g)+H20+2Cl(aq)

23. MASS CULTIPLICATION OF THE
BACILLUS SUBTILIS
 About 500ml of nutrient broth was prepared and sterilized
aseptically the pure culture of the bacillus subtilis were
inoculated into different conical flasks and incubated at 370
for 3-4 days.
 The cell concentration was measured by direct microscopic
method using haemocytometer and further used for
application the brick specimens.
PREPARATION OF MEDIA
 The nutrient media contains Peptone: 5g/lt, beef Extract: 3
g/lt, NaCl: 5 g/lt, Urea: 20g/lt, Calcium source: 49 g/lt.

24. METHOD OF TREATMENT
 The bacteria were cleaned from culture residues by
repeated centrifugation
 and re-suspension of obtained cell pellet in clean tap
water before the treatment process.
 Before using the number of bacteria cells in
suspensions were quantified my microscopic analysis,.
 and number of bacteria in resulting specimen amounted
to bacillus subtilis 7.2x105 cells/ml.

25. CURING OF BRICKS (28 & 14 DAYS)
 The bricks were cured for 14 and 28 days by addition of
nutrient media (say 20 and 10 ml) for fourteen bricks.
 The nutrient media was distributed uniformly throughout the
brick so that the bacteria stimulates and produces calcite
precipitation which strengthens the brick.
 After 14th day and 28th day curing, the bricks were kept in
sunlight for air drying and then in were tested in UTM
machine to determine its compressive strength.

26. COMPRESSIVE STRENGTH TEST
 The cubes were tested in 2000kN capacity, compressive
testing machine loaded at constant rate of loading at
200kg/cm2/min as per standard procedure explained in
IS: 516-1959(1999) to get the compression strength of
concrete.
Calculation
Max. Load at failure
Compressive strength --------------------------------
Area of brick

27. The following observations are made on each
test specimen:
 Identification mark
 Date of test
 Age of specimen
 Airing conditions, including date of manufacture of specimen in the
field
 Weight of specimen

28.  Dimensions of specimen
 Cross-sectional area
 Maximum load
 Compressive strength and
 Appearance of the failure observed under the UTM machine

29. APPARATUS
 Bricks
 Oven
 Venire caliper
 Scale

30. CONCLUSION
1. Water absorption
2. Porosity
3. Compressive strength
All specimen will prepared with replacement of cement by fly ash
with ratio of 10%, 15% & 20% and all the specimen will be tested
on 3rd day, 7th day and 21st day from brick casted.