chapter-4 materials and experimentation...
TRANSCRIPT
54
CHAPTER-4
MATERIALS AND EXPERIMENTATION
4.1 GENERAL
The present chapter deals with the properties of materials used in this
investigation. The various materials used in this investigation are cement, fine
aggregate, metakaolin, phosphogypsum, superplasticizer, various chemicals and
water. This chapter also highlights the testing of materials used in this investigation.
4.2 MATERIALS
The materials used in this experimental investigation include
1. Cement
2. Coarse aggregate
3. Fine aggregate
4. Metakaolin
5. Phosphogypsum
6. Water
7. Super-plasticizer Glenium B-233
8. NaCl, KCl, Na2SO4, CaCO3, Na2CO3, NaHCO3, CaCl2, MgSO4, HCl and
H2SO4 with different concentrations in mixing water.
4.2.1 Cement
Ordinary Portland cement of 53 grade conforming to ISI standards has been
procured. Following tests have been carried out according to IS: 8112 – 1989 on the
cement samples.
a) Specific gravity of Cement
b) Normal Consistency of Cement
c) Initial and Final setting time of Cement
55
d) Compressive Strength of Cement
e) Chemical compositions
The results of above tests are presented in Tables 4.1 and 4.2
Table 4.1: Physical properties of Cement
S.No Property Values
1 Fineness of Cement 225 m2/kg
2 Specific Gravity 3.1
3 Normal Consistency 29 %
4
Setting Time
i) Initial Setting time
ii) Final setting time
105 mins
350 mins
5
Compressive Strength
i) 3 days
ii) 7 days
iii) 28 days
32 N/mm2
46 N/mm2
58 N/mm2
Table 4.2: Chemical composition of cement
Lime (CaO) 63.70 %
Silica (SiO2) 22.00 %
Alumina (Al2O3) 4.25 %
Iron Oxide (Fe2O3) 3.40 %
Magnesia (MgO) 1.50 %
Sulphur trioxide 1.95 %
56
4.2.2 Fine aggregate and Coarse aggregate
The locally available river sand conforming to grading zone-II of Table 4 of IS
383-1970 has been used as Fine Aggregate. Following tests have been carried out as
per the procedure given in IS 383-1970 and the results are presented in Tables 4.3 &
4.4.
a) Specific Gravity
b) Bulk Density
c) Grading
d) Fineness Modulus of Fine Aggregate
The coarse aggregate of sizes 20mm and 12.5mm have been used. The
properties of these are presented in tables 4.5, 4.6 and 4.7.
Table.4.3: Sieve Analysis of Fine aggregate
S.
No.
I.S Sieve
Designation
Weight
retained
gm
Cumulative
weight
retained
Cumulative
percentage
retained
Cumulative
percentage
Passing
1 10mm 0 0 0 100
1 4.75mm 0.021 0.021 2.10 97.9
2 2.36mm 0.039 0.060 6.00 94
3 1.18mm 0.180 0.240 24.00 76
4 600 0.316 0.556 55.60 44.4
5 300 0.355 0.911 91.10 8.9
6 150 0.075 0.986 98.60 1.4
7 Pan 0.014 1 -------- -----------
Total = 277.4
Fineness Modulus = 2.77
57
Table4.4: Physical Properties of Fine aggregate
S. No. Property Value
1 Specific Gravity 2.69
2 Fineness Modulus 2.77
3 Bulk Density
i) Loose
ii) Compacted
14.57 kN/m3
16.25 kN/m3
4 Grading Zone - II
Table 4.5: Physical properties of Coarse aggregate
S.No Property Values
20mm 12.5mm
1 Specific Gravity 2.70 2.70
2
Bulk Density
i) Loose State
ii) Compacted
State
15.36 KN/m3
17.26 KN/m3
14.13 KN/m3
16.88 KN/m3
3 Water Absorption 0.2% 0.3%
4 Flakiness Index 9% 14.22%
5 Elongation Index 12% 21.33%
6 Crushing Value 13.45% 21.43%
7 Impact Value 11.26% 15.5%
8 Fineness Modulus 5.411 4.352
58
Table 4.6 Sieve Analysis of Coarse aggregate (20 mm)
S. No
IS Sieve
Weight
retained
(kg)
Cumulative
Weight
retained
(kg)
Cumulative
% weight
retained
Cumulative
% Passing
1 40 mm 0 0 0 100
2 20 mm o.305 0.305 6.1 93.9
3 16 mm 2.560 2.865 57.3 42.7
4 12.5mm 1.320 4.185 83.7 16.3
5 10mm 0.570 4.755 95.1 4.9
6 4.75 mm 0.200 4.955 99.1 0.9
7 2.36 mm 0.035 4.99 99.8 0.2
8 1.18mm 0.010 5 100 0
Fineness modulous=5.411
Table 4.7 Sieve Analysis of Coarse aggregate (12.5 mm)
S. No
IS Sieve
Weight
retained
(kg)
Cumulative
Weight
retained (kg)
Cumulative
% weight
retained
Cumulative
% Passing
1 20 mm 0 0 0 100
2 16 mm 0.445 0.445 8.9 91.1
3 12.5 mm 1.260 1.705 34.1 65.9
4 10 mm 2.970 4.675 93.5 6.5
5 4.75 mm 0.280 4.955 99.1 0.9
6 2.36mm 0.025 4.980 99.6 0.4
7 1.18mm 0.020 5 100 0
Fineness Modulus = 4.352
59
Fig: 4.1 View of cement, fine aggregate and coarse aggregate
4.2.3 Properties of Metakaolin
Metakaolin obtained from KOAT manufacturing company, Vadodara, Gujarat
has been used. Metakaolin is a dehydroxylated form of the clay mineral
kaolinite.Rocks that are rich in kaolinite are known as china clay or kaolin,
traditionally used in the manufacture of porcelain. The particle size of metakaolin is
smaller than cement particles, but not as fine as silica fume. Metakaolin is
a pozzolanic additive product which can provide many specific features. It is available in
many different varieties and qualities. The purity will define the binding capacity for free
lime. Some of them also provide special reactivity.
Metakaolin is a valuable admixture for concrete applications. Usually 8% - 20%
(by weight) of Portland cement is replaced by metakaolin. Such a concrete exhibits
favorable engineering properties. The pozzolanic reaction starts soon and continues
between 7 to 28 days.
60
Fig. 4.2 View of the metakaolin
Table 4.8: Physical properties of metakaolin (KOAT manufacturing company,
Vadodara, Gujarat)
S.No Property Value
1 Brightness(ISO) 82±2
2 Yellow index 2.2 to 2.5
3 Bulkdensity(gm/L) 300 to 340
4 Average particle size 1.5 to 2.5 micron
5 Residue (>45 micron) (max%) 0.5 to 2 %
6 Moisture content ≤1%
7 Specific surface area BET (m2
/gm) 12-18
Table 4.9: Chemical properties of metakaolin
(KOAT manufacturing company, Vadodara, Gujarat)
S.No Chemical analysis Percentage
1 SiO2 51-54%
2 Al2O
3 41-44%
3 Fe2O
3 0.35%
4 TiO2 0%
5 CaO 0.02%
6 MgO 0.07%
7 K2O 1-2%
8 Na2O 0.13%
61
4.2.4 Properties of Phosphogypsum
The Phosphogypsum used in the investigation was obtained from Coromandel
international Ltd, Ennore, Chennai. The Phosphogypsum passing through 90 sieve
was used throughout the experiment. The specific gravity of Phosphogypsum was
found to be 2.34. The properties of PG used in this study are presented in Table 4.10.
Table 4.10: Chemical composition of phosphogypsum (Coromandel international
Ltd, Ennore, Chennai)
S.No Chemical Percentage
1 CaSO42H2O 92.0-94.0
2 SiO2+insolubles 4.0 max
3 Fe2O3+Al2O3 0.3 max
4 CaO 30.0-31.0
5 MgO 0.1 max
6 Na2O+K2O 0.3-0.4 (0.5 max)
7 Total P2O5 0.6-1.0
8 Total SO3 42.8-44.0
9 Fluorides as F 0.4-0.5(0.7 max)
10 Chlorides as C 0.3-0.5(0.6 max)
11 pH of 10% solution 5.0-6.0(4 min)
62
Fig.4.3: View of phosphogypsum
4.2.5 Properties of Water
Deionised water has been used for mixing as well as curing of concrete in the
present investigation. The characteristics of deionised water, to which various
chemical substances were spiked to obtain neutral salt, strong alkaline, slightly acidic
and acidic water, are presented in the table
Table 4.11: Characteristics of Deionised Water
SI. No. Parameter Amount
1 pH 9.7
2 TDS(mg/L) 6.5
3 Alkalinity(mg/L) 9
4 Acidity(mg/L) 2
5 Hardness(mg/L) 1
6 Sulphates(mg/L) 0.3
7 Chlorides(mg/L) 9
63
The control sample which is prepared with deionised water as mixing water
and did not contain any chemical additives was used as the basis of comparison for
examining the effects of the chemicals on the properties of HPC.
4.2.6 Properties of Superplasticizer
GLENIUM B233 is an admixture of a new generation based on modified
polycarboxylic ether. The product has been primarily developed for applications in
high performance concrete where the highest durability and performance is required.
GLENIUM B233 is free of chloride & low alkali. It is compatible with all types of
cements.
Uses
Production of Rheodynamic concrete
High Performance Concrete for Durability
High early and Ultimate Strength Concrete
High Workability without segregation or bleeding
Precast or Pre-stressed concrete
Concrete containing pozzolans such as microsilica , GGBFS ,PFA including
high volume fly ash concrete
Advantages
Elimination of vibration and reduced labour cost in placing
Marked increase in early & Ultimate Strengths
Higher E modulus
Improved adhesion to reinforcing and stressing steel
64
Better resistance to Carbonate and other aggressive atmospheric conditions
Lower permeability – increased durability
Reduced shrinkage and creep
Dosage
Optimum dosage of GLENIUM B233 was found out by Marsh cone test. A
graph was plotted connecting marsh cone time in seconds and dosage of
superplasticizer. The dose at which the Marsh cone time is lowest is called the
saturation point. That dose is taken as the optimum dosage. In the present
investigation 1% by weight of cement is the optimum dosage.
Typical properties as supplied by the manufacturer:
Aspect: Light brown liquid
Relative Density: 1.08 ± 0.01 at 25°C
pH: >6
Chloride ion content: < 0.2%
Effects of over dosage:
Extension of initial and final set
Bleed/Segregation of mix , quick loss of workability
Increased plastic shrinkage
65
Fig4.4: Chemical admixture GLENIUM B233
4.2.7. Chemical substances
From the past literature various researchers have collected water samples from
different water bodies and also from various industrial chemical effluents were
collected and analysed for chemical and biological components. Among these
components, the most commonly found components were identified along with their
concentrations in treated effluents. Based on this information various chemical
components were selected for the experimental work. The chemical substances were
further categorized in to four major divisions viz., i) Neutral salts ii) Strong Alkaline
substances iii) Slightly Acidic substances and iv) Strong Acids.
Table 4.12 below gives the list of chemical substances along with the range of
concentrations and pH values in effluents.
66
Table 4.12: Classification and details of chemical substances
4.3. EXPERIMENTATION
4.3.1. Test Programme
The details of the specimens used in the experimental work are presented in
Table 4.13. A total of 288 samples of standard moulds used in Vicat’s apparatus were
cast and tested for initial and final setting time experiments. A total of 432 samples of
concrete were used in compaction factor test and 432 samples of concrete were used
in vee-bee time test. A total of 1296 concrete cubes of (15x15x15 cm) 225 cm2 cross-
S. No. Name & symbol Range of
concentration
Range of
pH
1
Neutral salts
a) NaCl
b) KCl
c) Na2SO4
d) CaCO3
0 – 30 g/L
0 – 5 g/L
0 – 20 g/L
0 – 0.3 g/L
7.0-7.01
7.0-7.05
7.0-7.04
6.9-7.1
2
Strong Alkaline
substances
a) Na2CO3
b) NaHCO3
0 – 20 g/L
0 – 20 g/L
8.3-11.20
7.6-9.7
3
Slightly Acidic
substances
a) CaCl2
b) MgSO4
0-2 g/L
0-1.5 g/L
7.2-6.2
7.10-6.13
4
Strong Acids
a)HCl
b)H2SO4
0-800 mg/L
0-800 mg/L
4.3-6.03
4.3-6.03
67
sectional area were tested at 7 days, 28 days and 90 days for compressive strength.
The same number of cylindrical samples of 15x15x30 cm3 were tested for split tensile
strength at 7 days, 28 days, and 90 days.
Table: 4.13: Details of test Programme
SNo.
Chemical Concent
ration
No. Of
Specimens
for
Setting
time test
No. Of
Specimens
for
compaction
factor test
No. Of
Specimens
for vee-
bee time
test
No. Of
Specimens
for
Compression
test
No. Of
Specimen
s
for Split
tensile
test To
tal
1 Deionised water
(control) -
3x2
3x3
3x3
3X 9
3X 9
78
2
NaCl (g/L)
0.5
2.0
4.0
10.0
20.0
30.0
3x2
3x2
3x2
3x2
3x2
3x2
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
78
78
78
78
78
78
3
KCl (g/L)
0.5
1.0
2.0
3.0
5.0
3x2
3x2
3x2
3x2
3x2
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
78
78
78
78
78
4
Na2SO4 (g/L)
0.5
2
4
6
10
20
3x2
3x2
3x2
3x2
3x2
3x2
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
78
78
78
78
78
78
68
5
CaCO3 (g/L)
0.01
0.1
0.2
0.3
3x2
3x2
3x2
3x2
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
78
78
78
78
6
Na2CO3(g/L)
0.5
2
4
10
20
3x2
3x2
3x2
3x2
3x2
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
78
78
78
78
78
7
NaHCO3(g/L)
0.5
2
4
10
20
3x2
3x2
3x2
3x2
3x2
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
78
78
78
78
78
8
CaCl2(g/L)
0.2
0.5
1
2
3x2
3x2
3x2
3x2
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
78
78
78
78
9
MgSO4(g/L)
0.2
0.5
1
1.5
3x2
3x2
3x2
3x2
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
78
78
78
78
10
HCl(mg/L)
50
100
400
800
3x2
3x2
3x2
3x2
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
78
78
78
78
11
H2SO4(mg/L)
50
100
400
800
3x2
3x2
3x2
3x2
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3x3
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
3X 9
78
78
78
78
Total 288 432 432 1296 1296 3744
69
4.3.2 Experimental Procedure
Normal consistency, initial and final setting times are determined by the
Vicat’s apparatus, which measures the resistance of cement paste of standard
consistency of the penetration of a needle under a total load of 300gm. The initial set
is an arbitrary time in the setting process, which is reached when the needle is no
longer able to pierce 40mm deep pat of the cement paste within about 5 to 7 mm from
the bottom. The final set is reached, when the needle makes an impression on the
surface of the paste but does not penetrate.Vicat’s apparatus confirming to IS 5513-
1976 consists of a frame to which a movable rod having an indicator is attached
which gives the penetration. The rod weighs 300 gm and has diameter and length of
10 mm and 50 mm respectively. Vicat’s apparatus includes three attachments –
plunger for determining normal consistency, square needle for initial setting time, and
needle with annular collar for final setting time. Detailed experimental procedures
adopted in the investigation are given in the following sections.
Fig.4.5: Vicat’s apparatus
70
4.3.2.1. Consistency
About 300gm of cement was initially mixed with 27 percent mixing water.
The paste was filled in the mould of Vicat’s apparatus and care was taken such that
the cement paste was not pressed forcibly in the mould and the surface of the filled
paste was not pressed forcibly in the mould and surface of the filled paste was
smoothened and leveled. A square needle of size 1 mm x 1mm x 1mm attached to the
plunger is then lowered gently on to the surface of the cement paste and is released
quickly. The plunger pierces the cement paste and the reading on the attached scale
was recorded. The experiment was performed carefully, away from vibrations and
other disturbances. The test procedure was repeated by increasing the percentage of
mixing water at 0.5% increment until the reading was 5 to 7 mm from the bottom of
the mould. When this condition is fulfilled, the amount of water added was taken as
the correct percentage of water for normal consistency. The entire test was completed
within 3 to 5 minutes. Fresh sample was taken for each repetition of the experiment.
The plunger was cleaned each time the experiment is done.
4.3.2.2 Initial setting time
Lower the needle gently and bring it in contact with the surface of the test
block and quickly release. Allow it to penetrate in to the test block .In the beginning
the needle will completely pierce through the test block. But after some time when the
paste starts losing its plasticity the needy may penetrate only to a depth of 33 – 35mm
from the top .The period elapsing between the time when water is added to the cement
and the time at which the needle penetrates the test block to a depth equal to 33-35mm
from the top is taken as initial setting time.
71
4.3.2.3. Final setting time
The cement shall be considered as finally set when , upon , lowering the
attachment gently cover the surface of the test block ,the center needle makes an
impression , while the circular cutting edge of the attachment fails to do so. In other
words the paste has attained such hardness that the centre needle does not pierce
through the paste more than 0.5mm.
4.3.2.4. Workability
All the mixes were evaluated for workability in terms of compaction factor
and vee-bee time.
4.3.2.4.1. Compaction factor test
The apparatus for conducting compaction factor test is depicted in Fig: 4.6.
The compaction factor test apparatus consists of two hoppers, each in the shape of
frustum of a cone and one cylinder. The upper hopper is filled with concrete this
being placed gently so that no work is done on the concrete at this stage to produce
compaction. The second hopper is smaller than the upper one and is therefore filled to
overflowing. The concrete is allowed to fall in to the lower hopper by opening the trap
door and then into the cylindrical mould placed at the bottom. Excess concrete across
the top of the cylindrical mould is cut and the net weight of the concrete in cylinder is
determined. This gives the weight of partially compacted concrete. Then the
cylindrical mould is filled with concrete in layers of 5cm depth by compacting each
layer fully. The fully compacted weight is then determined and compaction factor
(C.F) is calculated as below.
Weight of partially compacted concrete
C.F. = -----------------------------------------------
Weight of fully compacted concrete
72
Fig. 4.6: View of the test setup for Compaction Factor
4.3.2.4.2 Vee-bee time test
The Vee-Bee consistometer test is suitable for mixes with low workability
whose slump cannot be measured with slump test. Since low water-binder ratios are
adopted in the production of HPC, this V-B test is quite suitable to find out the
workability. The apparatus for conducting Vee-Bee test is depicted in Fig. 4.7.
Placing the slump cone inside the metal cylindrical pot of consistometer the slump
test is performed. The glass disc attached to the swivel arm is turned and placed on
the top of the concrete in the pot. The electrical vibrator is then switched on and
simultaneously a stopwatch is started. The vibration is continued till such a time as
the conical shape of concrete disappears and the concrete attains a cylindrical shape.
This can be judged by observing the glass disc from the top for disappearance of
73
transparency. Immediately when the concrete fully attains a cylindrical shape, the
stopwatch is switched off. The time required for the concrete to change from slump
cone to cylindrical shape in seconds is known as Vee-Bee degree.
Fig.4.7: View of the test setup for Vee-Bee Time
4.3.2.5 Casting of cubes and cylinders
The mix ratio of cement: sand: coarse aggregate is 1:0.76:1.8 with water/ binder ratio
as 0.3. The mix proportion was arrived by trial and error method as suggested by Vaishali
(2008). The dosage of superplasticizer is 1% by weight of cement. Total three mixes were
used. First mix with only OPC, second mix with 20 % replacement of Cement with
Metakaolin and third mix was with 20 % replacement of cement with Phosphogypsum.
The cubes were cast in steel moulds of inner dimensions of 150 x 150 x 150mm and
the cylinders were cast in steel moulds of inner dimensions as 150mm diameter and
300mm height.
The cement, sand, coarse aggregate, metakaolin/phosphogypsum were mixed
thoroughly manually. The Super plasticizer is mixed in half of the water required for
74
casting and the specified chemical is mixed in another half water. After that, 50% of
water with chemical was first added, mixed thoroughly and then the water with
superplasticizer is added and mixed. Care has to be taken in mixing to avoid balling
effect. For all test specimens, moulds were kept on floor and the concrete was poured
into the moulds in three layers by tamping with a tamping rod.
Fig. 4.8: View of the Concrete filled in the Moulds
4.3.2.6 Curing
The moulds were removed after 3 days and the specimens were kept immersed
in deionised water mixed with the specified chemical with specified dosage. After
curing the specimens were tested for 7 days, 28 days and 90 days compressive
strength .The specimens were tested for 90 days compressive strength also are cured
for only 28 days. They are kept outside after 28 days till 90 days testing.
4.3.2.7. Cube compressive strength test
The test set up for conducting cube compressive strength test is depicted in
Fig. 4.9. Compression test on the cubes is conducted on the 2000 KN AIMIL - make
digital compression testing machine. The pressure gauge of the machine indicating the
load has a least count of 1 KN. The cube was placed in the compression-testing
75
machine and the load on the cube is applied at a constant rate up to the failure of the
specimen and the ultimate load is noted. The cube compressive strength of the
concrete mix is then computed. This test has been carried out on cube specimens at 7
days, 28 days and 90days age.
Fig. 4.9: Compressive Strength test set up
4.3.2.8 Split tensile strength
This test is conducted on 2000 KN AIMIL make digital compression testing
machine as shown in Fig. 4.10. The cylinders prepared for testing are 150 mm in
diameter and 300 mm long. After noting the weight of the cylinder, diametrical lines
are drawn on the two ends, such that they are in the same axial plane. Then the
cylinder is placed on the bottom compression plate of the testing machine and is
aligned such that the lines marked on the ends of the specimen are vertical. Then the
top compression plate is brought into contact at the top of the cylinder. The load is
applied at uniform rate, until the cylinder fails and the load is recorded. From this
76
load, the splitting tensile strength is calculated for each specimen. In the present work,
this test has been conducted on cylinder specimens after 7 days, 28 days and 90 days.
Fig.4.10: Split tensile strength test set up
4.3.2.9 Powdered X-ray diffraction studies
Powered X-ray diffraction (XRD) is one of the most widely used and useful
technique for investigation of both quantitative and qualitative phase analysis and
provides information regarding specific components. In the powder diffraction
analysis information relating to the structure of the substance and its allotropic
transformation, transition to different phases and the purity of the substances are
obtained. The samples under investigation for the XRD were grounded well to a fine
powder and a flat specimen was prepared on a glass substrate with each sample using
adhesive material. The specimen was placed on the Gonio-meter and diffracted
77
intensities (peaks) were recorded with powder diffractometer using monochromatic
copper Kα radiation. X-ray diffraction analysis for concrete samples was carried out
at College of chemical technology, Osmania University, Hyderabad.
Fig.4.11: XRD testing machine
4.3.2.10 Scanning electron microscopy (SEM)
The concrete samples were broken in to samples, coated with nickel and
examined under the scanning electron microscope and SEM photographs were taken.
SEM analysis for concrete samples was carried out at College of Chemical
Technology, Osmania University, Hyderabad.
78
Fig.4.12: SEM testing machine
4.4. CLOSURE
Various tests on raw materials viz. cement, fine aggregate, coarse aggregate,
metakaolin and phosphogypsum have been conducted to confirm their suitability for
use in concrete making as per the procedures as in I.S.codes. It is observed that all the
materials satisfy the relevant provisions of Indian Standard code of practice. The
results of various tests are presented in this chapter.
A total of 288 samples were cast and tested for initial setting time and 288
samples for final setting time experiments were casted and tested. A total of 432
samples of concrete were used in compaction factor test and 432 samples of concrete
were used in vee-bee time test. A total of 1296 concrete cubes casted and were tested
at 7, 28 and 90 days for compressive strength. The same number of cylindrical
samples were tested for split tensile strength test at 7, 28 and 90 days. The details of
the experimentation have been presented in this chapter. In the next chapter the details
of experimental investigation and a useful discussion of test results will be presented.