012- Sulphuric Resistant Geopolymer
-
Upload
fcofimeuanl -
Category
Documents
-
view
233 -
download
0
Transcript of 012- Sulphuric Resistant Geopolymer
8/9/2019 012- Sulphuric Resistant Geopolymer
http://slidepdf.com/reader/full/012-sulphuric-resistant-geopolymer 1/11
Indian Journal of Engineering & Materials SciencesVol. 19, October 2012, pp. 357-367
Sulphuric acid resistant ecofriendly concrete from geopolymerisation of blast
furnace slag
N P Rajamanea*, M C Nataraja
b, N Lakshmanan
c, J K Dattatreya
d & D Sabitha
e
aSRM University, Kattankulathur 603 203, India,bDepartment of Civil Engineering, S J College of Engineering, Mysore 570 006, India
cCSIR-Structural Engineering Research Center, Chennai 600 113, IndiadSiddaganga Institute of Technology, Tumkur 572 103, India
eCSIR-National Geophysical Research Institute, Hyderabad 500 007, India
Received 13 July 2011; accepted 11 September 2012
In this study, geopolymer is prepared from ‘ground granulated blast furnace slag’ (GGBS)–a powder from grinding the
by-product of slag waste from blast furnace of steel plants. For comparison, conventional cement, Portland pozzolanacement (PPC) containing fly ash was considered. To achieve simultaneous acidic and sulphate attack, sulphuric acid is usedfor durability studies. The test data indicate that on exposure to 2% and 10% sulphuric acids, the losses in weight, thickness
and strength of geopolymer concrete (GPC) are significantly much less than those for Portland pozzolana cement concrete(PPCC). The GPCs have inorganic polymers of alumino-silicates as binder, generally without any free lime. Therefore,GPCs resist acid attack better than free lime containing conventional concretes containing Portland cement. The bindingaction in GPC is through geopolymerisation of GGBS using alkaline activator solution (AAS) made of sodium hydroxide
and sodium silicate solutions. The geopolymer eliminates use of Portland cement in structural concretes by utilizing theindustrial by-product GGBS, thereby reducing considerably the carbon footprint measured by ‘embodied energy’ and‘embodied carbon’, i.e., ‘CO2e emission’ of concrete.
Keywords: Geopolymer, Sulphuric acid, Portland pozzolana cement, Fly ash, Blast furnace slag powder, Sodium hydroxide,
Sodium silicate
Portland cement, a conventional binder in concretes,has performed satisfactorily in most of the civil
engineering applications1,2. However, this cement is
highly internal-energy-intensive (with high ‘embodied
energy’ contents) and also, its production involves
emission of green house gas of CO22 and concrete
made with this cement were observed to be less
durable in some of the very severe environmental
conditions3,4. These facts have urged engineers to look
for development of alternate concretes. In this regard,
geopolymer concretes (GPCs) have emerged as
potential candidate materials5-12
.
These new concretes utilise industrial wastes in theform of fly ash (FA) and ground granulated blast furnace
slag (GGBS) which are activated by alkaline medium to
produce ambient temperature cured inorganic polymeric
binder (called as geopolymers) in the form of alumino-
silicates. However, in order to make these new concretes
acceptable in practical applications, they should be
shown to possess both adequate strength and durability
characteristics. These aspects were studied in the
extensive investigations carried out at CSIR-SERC,Chennai
13-18. The test results discussed in this paper are
with regards to sulphuric acid resistance of GPC made
from GGBS only. Since the above mentioned industrial
wastes become ‘geopolymeric resource material’, they
can be now considered as by-products, instead of so
called waste. Though the term, ‘geopolymer’ has
become now more common to represent the synthetic
alkali aluminosilicate material (produced by reaction of
a solid aluminosilicate with a highly concentrated
aqueous alkali hydroxide or silicate solution), it is
worthwhile to note that the following nomenclatures are
also reported to describe similar materials: (i) inorganicpolymer19, (ii) low-temperature aluminosilicate glass20-22,
(iii) alkali-activated cement23-25, (iv) alkali-activated
binders26-27
, (v) geocement
28, (vi) alkali-bonded ceramic
29
(vii) inorganic polymer concrete30
, (viii) hydroceramic
31,
(ix) mineral polymers32, (x) inorganic polymer glasses33,
(xi) alkali ash material34, (xii) soil cements35, (xiii) alkali
activated aluminosilicate36
It is seen that ‘geopolymer’ is a versatile binder
being studied by scientists of various backgroundsand expertise, but, having good potential to become
__________*Corresponding author (E-mail:[email protected] )
8/9/2019 012- Sulphuric Resistant Geopolymer
http://slidepdf.com/reader/full/012-sulphuric-resistant-geopolymer 2/11
INDIAN J ENG. MATER. SCI., OCTOBER 2012358
eco-friendly alternate to Portland cement for use incivil engineering applications. But, to understand
various aspects of this new material from the
literature, it is necessary to consider the abovenomenclatures also so that the information available
in various forums is readily utilised. In the presentpaper, more widely used term, ‘geopolymer’ is
adopted for presentation of data and discussion.
Aims of Present Study Since Portland pozzolana cement (PPC) is the most
easily available cement in the market at present, it
was chosen to produce a typical conventional cement
concrete. GGBS based GPC mix was selected based
on the earlier works carried out at CSIR-SERC. The
cylindrical specimens (75 mm dia × 75 mm height)were employed for studying the resistance of
concretes to 2% and 10% sulphuric acid solutions and
100 mm cubes for evaluating compressive strengths.
Besides visual observations, changes in weight and
strength after predetermined exposure periods to acid
were recorded. The sulphuric acid resistance test is a
very severe durability test on concretes since this acid
combines the effects of both acidic and a sulphate
environment simultaneously and therefore, the actual
test duration is much shorter than many otherdurability tests.
GPC being a new material of construction, requiresto be assessed for both strength and durability
characteristics. The GPC utilises industrial by-productof blast furnace slag from steel plants. The test data in
this paper is expected to enable the engineers to
examine the durability aspects of the GPC from
GGBS which is obtained after grinding the slag and
consider them for construction of actual structures.The test data of this study provides a basis for
complete elimination of highly energy intensive
Portland cement from concrete which is the most
widely used construction material. The new concrete
produced from the industrial by-product slag wouldnot only have low carbon footprint with low
‘embodied energy’ and ‘low carbon dioxide
emission’, but also it is more durable material with
higher and faster strength development capability.
Though this paper deals with sulphuric acid
resistance of concretes, it is necessary to look at many
other parameters such as sulphate attack, chloride
diffusion, water absorption, stability of geopolymeric
gel formed, bond strength of GPC with steel bars,corrosion protection to embedded steel, alkalinity
level of matrix formed and flexural and otherstructural behaviour of reinforced concrete sections
are also important. These aspects are covered in many
earlier studies
37-44
. However, we must note that‘geopolymer’ is a very generic word and this can form
from a variety of geopolymeric source materials, suchas fly ash, GGBS, metakaolin, rice husk ash, synthetic
alumina and silica apart from possibility a large
number of activator solution formulations. Therefore,
unlike, Portland cement, careful understanding of
different geopolymeric composites is necessary.
Experimental ProcedureMaterials
Properties of materials are described in Tables 1a-1f.
It may be noted here that any concrete requires fine
aggregates (particles smaller than 4.75 mm) andcoarse aggregates (particles larger than 4.75 mm) so
that a packing of these two inert filler materials
creates minimum space for binder paste in the
concrete mix and this is required from economic point
of view also since binder portion is generally the most
expensive in any concrete mix. The river sand as fine
aggregate and crushed granite stone as coarse
aggregate are very commonly adopted for
conventional concrete mixes and the same were
chosen for GPC mixes. The test data also showed that
the chosen aggregates act satisfactorily as almost inert
filler system in both types of concretes.The fly ash described in Table 1c is Class F and
was obtained from North Chennai Thermal Power
Plant where fly ash is being collected dry through
electrical precipitators.
Preparations of test specimens
The mix proportions (Table 2) were arrived by trial
mixes, so that the satisfactory workability with a
slump cone value of at least 100 mm is achieved and
the mix was easily compactable by a laboratory table
Table 1a—Properties of Portland pozzolana cement (PPC)
Sl.No
Descriptions PPC
1 Fineness (cm2 /g) 306
2 Normal consistency (%) 31
3 (a) Initial setting time (min) 55
(b) Final setting time (min) 100
4 (a) Soundness Le Chatelier expansion (mm) 0.5
(b) Soundness autoclave expansion (%) 0.08
5 Compressive strength (MPa) at 28 Days 56
6 Specific gravity 3
9 Loss on ignition (%) 1.31
8/9/2019 012- Sulphuric Resistant Geopolymer
http://slidepdf.com/reader/full/012-sulphuric-resistant-geopolymer 3/11
RAJAMANE et al.: GEOPOLYMER CONCRETE 359
vibrator. Ingredients were weighed in digital balances;
mixing was done in a pan mixer for a minimum period
of 5 min to achieve the uniformity in the mix. Thefreshly prepared mix was weighed for density and
placed into the steel mould in three layers andcompacted using a laboratory table vibrator. The
specimens were demoulded after 24 h of casting. GPC
specimens were self cured by storing them openly underambient laboratory conditions (temperature 25-35ºC,
relative humidity of 65-85%). The conventional
Portland pozzolana cement concrete (PPCC) specimens
were kept submerged in water for effective curing.
The alkali activator solution (AAS) mentioned inTable 2 is made from the mixture of sodium
hydroxide solution and sodium silicate solution. The
quantity of this liquid AS taken was 55% by weight of
binder which, in the present case of GPC is GGBS.
This binder/AAS ratio of 0.55 provided sufficientworkability to the fresh GPC mix. The AAS can be
considered to be consisting of Na2O and SiO2 besideswater. As Na2O is more important from
geopolymerisation point of view, its content with
reference to geopolymeric binder was computed andthis was found to be about 5% as mentioned in Table 2.
Acid attack test on concrete specimens
The concentrated sulphuric acid (98% concentration
and density of 1.84 g/cc) was used to prepare thesulphuric acid of 2% and 10% concentrations. For this,
following formula was used:
Table 1b—Properties of ground granulated blast furnace slag (GGBS)
Chemical compositionLoss ofignition %
Glasscontent %
Finenesscm2 /g
Specificgravity CaO SiO2 Al2O3 Na2O KO MgO LOI
2.1 85 4000 2.92 40.3 43.4 12.5 0.9 0.6 1.5 2.1
Table 1c—Properties of fly ash
S. No Components IS 3812 (2003)Specifications
Fly ash used
1 SiO2 + Al2O3 +Fe2O3 70% min 98%
2 SiO2 35% min 59%
3 Al2O3 - 31%
4 Fe2O3 - 8%
5 MgO 5% max 0.22-0.34%
6 Total sulphur as SO3 2.75% max -
7 Alkalis as Na2O 1.5 % max 0.54%
8 LOI 12% max 1.05-1.08%
9 CaO - 0.86-1.02%
10 Specific gravity - 2.2
11 Bulk density - 950 kg/m3
12 Fineness (Blaine) - 3435 cm2 /gm
Table 1f—Properties of Sodium hydroxide flakes (SHf)
Property Literature* Present study
Molecular formula NaOH NaOH
Molar mass 39.9971 g/mol 40 (used for computation)
Appearance White solid White solid
Density and phase 2.1 g/cm³, solid 2.1 g/cm³, solid
Solubility in water 111 g/100 mL (20°C) Could easily dissolve 100 g in 100 mL of distilled waterat ambient temperature of 30°C
Melting point 318°C Not determined
Boiling point 1390°C Not determined
Basicity (pKb) -2.43 -Not determined
Exposure to air Highly hygroscopic in nature Observed to be highly hygroscopic
Amount of heat liberated
when dissolved in water
44.45 kJ/mol = 1.1111 kJ/g = 266 calories/gram Not determined
Storage Air tight container (absorbs CO2 from the air) Stored in air tight container
* http://www.answers.com/library/Wikipedia-cid-76614
Table 1d—Properties of aggregates
Sl. No Property Coarse aggregate Fine aggregate
1 Specific gravity 2.72 2.65
2 Water absorption 1.20 % 0.50 %3 Fineness modulus 6.68 2.44 Bulk density 1650 kg/m3 1550 kg/m3
5 Source Crushed granite stone River bed
Table 1e—Properties of sodium silicate solution
Property Literature* Present study
Specific Gravity 1.56-1.66 1.62Na2O 15.5-16.5 16.1
SiO2 31-33 32.1Weight ratio 2.2 2.0Molar ratio 2.2 1.94Iron content, ppm <100 58
*Source : http://www.pqcorp.com (URL4)
8/9/2019 012- Sulphuric Resistant Geopolymer
http://slidepdf.com/reader/full/012-sulphuric-resistant-geopolymer 4/11
INDIAN J ENG. MATER. SCI., OCTOBER 2012360
R = D1 * [(C1 / C2) - 1] … (1)
where, C1 is %concentration of commercially
available conc. sulphuric acid, D1 is density of conc.
sulphuric acid of concentration C1 (g/mL), C2 is%concentration of desired diluted sulphuric acid for
testing, R is volume of water added per mL of
sulphuric acid of concentration, C1 to get diluted
sulphuric acid of concentration, C2
Thus, it was noted that about 11 mL of 98%
concentrated sulphuric acid (conc. H2SO4) was
required to be mixed with 989 mL of distilled water to
get 1 L of 2% acid solution for test. On the other
hand, 1 L of 10% acid solution is obtained by mixing
58 mL of 98% concentrated sulphuric acid (conc.
H2SO4) with 942 mL of distilled water. The
cylindrical specimens were submerged in acidsolution kept in a plastic tubs such that there was a
minimum of 30 mm depth of acid over the top surface
of specimens. The pH of the solution was monitored
periodically using pH meter and also by titration with
standard alkaline solution. The specimens are taken
out from acid tank at the end of each test period for
visual observation for deteriorations and washed in
the tap water before weighing in digital balance of 0.1
mg accuracy and then testing for compressive strength
in an UTM.
Results and Discussion
Fresh concrete properties
The workability of all the concrete mixes (measured
by Abram’s Slump Cone following the procedure
given in IS:1199) was more than 100 mm which wassufficient for satisfactory compaction by use of table
vibrator. The mixes were also cohesive with almost
zero or very little bleeding. The fresh concrete density
of GPC and PPCC were almost similar (Table 2).
Though setting times of GPC were not measured
explicitly, however, they were found to be satisfactory
for GPC mix by observing that the minimum working
time available for fresh GPC mix was about 45 min
and the demoulding operations could be easily carriedout after 24 h of casting.
Efflorescence in GGBS based geopolymer was not
observed in the present study, though it has beenreported by some workers. But, during study on several
GPC mixes, depending upon the formulation of alkali
activator solution, authors noticed that sometimes,
greenish layer gets formed on surface of test specimens
made of some GPCs. This did not affect the structural
properties of GPCs. OPC based concretes, however,
did not show noticeable efflorescence.
The shrinkage characteristics of the mixes were not
measured directly in the present study. However, by
careful inspection of the different mixes prepared, it
Table 2—Details of concretes
1 Mix Id GPC PPCC
% Fly ash 0 28
% GGBS 100 0
2 Binder composition (% by mass)
% Portland Cement 0 72
3 Binder/ Activator solution 0.55 0.40
4 Activator solution (AS) AAS Water
5 Na2O in AS* as % binder 5.6 0
6 Superplasticiser % Binder 0 1.00
7 Slump, mm 120 115
8 Density, kg/m3 2375 2380
9 Ingredient contents of concretes, kg/m3
Fly ash 0 110
Ground granulated blast furnace slag (GGBS) 428 0
Portland cement 0 283
Binder 428 393Sand 642 814
Coarse aggregate 1070 1015
Activator solution, kg/m3 235 157
Alkali activator solution specific gravity 1.16 1.00
Activator solution, L/m3 203 157
GPC = Geopolymer Concrete, PPCC=Portland Pozzolana Cement Concrete, AAS=Alkali Activator solution
8/9/2019 012- Sulphuric Resistant Geopolymer
http://slidepdf.com/reader/full/012-sulphuric-resistant-geopolymer 5/11
RAJAMANE et al.: GEOPOLYMER CONCRETE 361
could be observed that the GPC mixes were almost
similar to Portland cement based concrete mixes.
Though some authors had reported noticeable
shrinkage of GPCs, the present formulation of the
GPC mix did not result in exhibition of shrinkage
related effects of the mixes.
Compression strength
The average 28 days compression strength of GPCwas 63 MPa which increased only marginally to 65
MPa at 90 days; corresponding values for PPCCs
were 48 and 74 MPa (Table 3a, Fig. 1a). Thus, GPC
had gained almost its full strength at the end of 28
Table 3a—Test data on concretes
1 Mix Id GPC PPCC
% Fly ash 0 28
% GGBS 100 0
2 Binder Composition (% by mass)
% Portland Cement 0 723 Binder/ Activator solution 0.55 0.40
4 Activator solution (AS) AAS Water
5 Na2O in AS* as % binder 5.6 0
Compressive Strength, MPa 1 day, fc1d 30 10
7 day, fc7d 44 24
28 day, fc28d 63 48
6
90 day, fc90d 65 74
Rate of strength development
fc1d /fc28d (%) 48 21
fc7d /fc28d (%) 70 50
fc28d /fc28d (%) 100 100
7
fc90d /fc28d (%) 103 154
Table 3b—Test data on concretes1 Mix Id GPC PPCC % Reduction in GPC*
Col(1) Col(2) Col(3)
% FA 0 28
% GGBS 100 02 Binder composition
%OPC 0 72
3 Binder/AS 0.55 0.40
4 Activator solution (AS) AAS Water
5 Na2O in AS* as % binder 5.6 0
Exposure to 2%H2SO4
30 days 0.1 2.3 96
60 days 2.7 6.3 576 Weight loss (%)
90 days 4.5 8.7 48
30 days 0.02 0.38 95
60 days 0.46 1.05 567 Thickness loss (mm)90 days 0.75 1.44 48
30 days 3.7 17.4 79
60 days 10 31.4 688 Strength loss (%)
90 days 11.1 36.2 69
Exposure to 10%H2SO4
30 days 2 4.4 55
60 days 5.3 21.8 769 Weight loss (%)
90 days 7.2 22.6 68
30 days 0.33 0.73 55
60 days 0.88 3.63 7610 Thickness loss (mm)
90 days 1.19 3.77 68
30 days 15.2 31.6 52
60 days 51.1 77.1 3411 Strength loss (%)
90 days 72.1 82.4 13
Note: Binder/AS ratio in PPCCs is water-binder ratio or water-cement ratioAS= Activator solution for GPC is made from mixture of sodium silicate (molar ratio 2.2) and sodium hydroxide solutions
GPC = Geopolymer cement concrete, PPCC=Portland pozzolana cement concrete% Reduction in GPC = 100*(OPCC-GPC)/OPCC
8/9/2019 012- Sulphuric Resistant Geopolymer
http://slidepdf.com/reader/full/012-sulphuric-resistant-geopolymer 6/11
INDIAN J ENG. MATER. SCI., OCTOBER 2012362
days where as PPCCs continued to gain considerable
strength after 28 days also (Fig. 1b). It may be noted
that these strength levels are quite adequate when
compared with the minimum structural grade
recommended in IS 456-2000 for ‘extreme’ exposure
condition. In present study, the 1 day strength of GPC
was about 30 MPa which is quite high and hence, the
present GPC may be considered as high early strength
concrete, which is useful in faster construction of
structures since the GPC studied does not require any
external curing and only ambient conditions are
enough for the geopolymerisation reactions and
subsequent strength gain. In contrast, OPC based
concretes need always careful curing through
exposure to moisture or water.
The data in Table 3a and Fig. 1b show that the
GPC has higher ratios of f 1d /f c28d and f 7d /f c28d than
those of PPCC indicating faster rate of development
than PPCC. The strength increase beyond 28 day up
to 90 day in case of PPCC is 54% which is substantial
as compared to this value being only about 3% forGPC, thereby confirming that the GPC develops fast
its ultimate strength compared to PPCC. This is a
useful and desirable property in structural concretes.
Sulphuric acid attack
Figures 2a-2c show a contrast between acid
resistances of GPC and PPCC specimens at for 30, 60
and 90 days of exposure to 2% sulphuric acids and the
difference increases with exposure time. The
percentages weight and strength losses for the mixes
and also estimated thickness loss due to attack by 2%
sulphuric acid increases with increased exposureperiod (Table 3b). At the end of 90 days, the PPCC
specimens were found to be in highly deteriorated
state with almost complete loss of integrity, but, theGPC specimens had almost maintained their integrity
with minor visible distress seen on the surface whenexamined visually, even though there were substantial
losses of strength (Figs 2a and 2b, 3a-3c). The %
strength losses in GPC after exposure of 30, 60 and 90
days to 2% H2SO4 were 3.7%, 10% and 11.1%
(corresponding weight losses being 0.1%, 2.7% and4.5%) respectively and these numbers for PPCC were
quite high at 17.4%, 31.4% and 36.2% (corresponding
weight losses being 2.3%, 6.3% and 8.7%) (Table 3b).
Fig.1a—Compressive strength of concrete mixes
Fig.1b—Compressive strength development
Fig. 2a—Percent weight loss on exposure to H2SO4
Fig. 2b—Thickness loss on exposure to H2SO44
Fig. 2c—Strength loss on exposure to H2SO4
8/9/2019 012- Sulphuric Resistant Geopolymer
http://slidepdf.com/reader/full/012-sulphuric-resistant-geopolymer 7/11
RAJAMANE et al.: GEOPOLYMER CONCRETE 363
Similar observations can be made in respect of depthof deterioration (thickness loss) also.
The above observations were valid also when the
loss of weight was converted into estimated averagedepth of deterioration due to penetration of sulphuric
acid computed using the following formula:
p = 1 - [{1 - 2 * (T /H1)} * {(1 - (T / R1) ^2}] … (2)
where,
T = estimated average depth of deterioration =Change in radius
H1 = initial height of specimen
R1 = initial radius of specimen before acid exposure
(R1 – T) = radius of specimen after exposure
(H1 – 2 * T) = height of specimen after exposure
P = fractional weight loss = (W1 – W2)/W1 =
weight loss/initial weightW1 = initial weight of specimen before acid exposure
W2 = weight of specimen after acid exposure
W1, W2, H1 and R1 are known, and T can be computed
from above equation. These values are given in Table
3b and Fig. 3a.
After 90 days, the PPCC specimens had typically
external exposure of the coarse aggregate; the
surfaces were rough and yellowish in colour (Figs 3b
and 3c). The expansive nature of chemical reaction
has happened in the PPCC specimens since aperceptible increase in porosity of specimens was
noticed. The free lime available in the hydrated
cement matrix get reacted by acid resulting in
formation of gypsum and also the calcium aluminate
phases of both hydrated and the unhydrated portions
of cement in the matrix also get attacked by sulphate
ions leading to formation of ettringite which is anexpansion creating compound3,4,43. These PPCC
specimens could be considered to have reached their
ultimate level of very existence itself. In contract, the
GPC specimens were almost intact even though
significant strength losses had occurred. This isevident from the estimated depths of deterioration
which were 0.02, 0.5 and 0.8 mm only, for 30, 60 and
90 days of 2% H2SO4 acid exposure for GPC whereas
these numbers for PPCC were as much as about 0.4,
1.1 and 1.5 mm (Fig. 2b).The above observations made on 2% sulphuric acid
are almost similarly valid for attack by 10% sulphuric
acid also (Fig. 2b). Thus, it is clear that GPC had
comparatively very high resistance to sulphuric acid
attack. The reductions in deterioration in respect of
Fig. 3a—Percent reduction of deterioration in GPC relative to PPCC
Fig. 3b—Specimens after exposure to 2% H2SO4
Fig. 3c—Specimens after exposure to 10% H2SO4
8/9/2019 012- Sulphuric Resistant Geopolymer
http://slidepdf.com/reader/full/012-sulphuric-resistant-geopolymer 8/11
INDIAN J ENG. MATER. SCI., OCTOBER 2012364
weight loss, deterioration depth, and strength loss can
be as much as 48% to 96% if PPCC is replaced by
GPC for 2% acid attack and this range becomes 13%
to 76% in case of 10% acid attack (column 3 in Table
3b, Fig. 3a). This can be attributed to the fact that the
GPCs do not have free lime content in its matrix and
geopolymers themselves are not easily attacked by
acids5.
Even though free lime was not measured in the
present case, published literature indicate that because
of nature of chemical reactions occurring ingeopolymer concretes, possibility of free lime is very
less and instead of calcium silicate hydrate (C-S-H)
gel (which is a binder portion in Portland cement
based matrix) aluminosilicate polymeric system isformed and this involves no evolution of free lime.
Superior acid resistances (particularly to sulphuric
acid) of geopolymer concretes in general have been
reported by many researchers44-45
. The PPCC do
contain free lime content in its matrix due tohydration reactions of Portland cement portion of the
PPC and this free lime and also the hydrated Portland
cement matrix C-S-H gel of the matrix are easily
attacked by acids in general, especially more by the
sulphuric acid 2,43
.
Ecological Analysis of ConcretesEmbodied energy (EE) and embodied carbon
(ECO2e) of concretes were computed to examine the
ecological effects of the concretes47,48
. The EE is the
energy consumed for the raw material extraction,
transportation, manufacture, assembly, installation,disassembly and deconstruction for any product system
over the duration of a product’s life. The embodied
carbon (ECO2e) is the CO2e released for the raw
material extraction, transportation, manufacture,
assembly, installation, disassembly and deconstruction
for any product system over the duration of a product’s
life. The data on EE and EC for the ingredients and the
concretes were taken from the literature47-53
. The
computations are shown in Table 4a and the benefit of
GPC over PPCC are given in Table 4b (Fig. 4).
Table 4a—Ecological analysis of concretes
Type of concrete Data for each material EE ECO2e Cost
GPC PPCC EE ECO2e Cost GPC PPCC GPC PPCC GPC PPCC
Ingredient kg/m3
kg/m3
MJ/kg kgCO2e/kg Rs/kg MJ/m3
MJ/m3
kgCO2e/m3
kgCO2e/m3
Rs/m3
Fly ash 0 110 0.1000 0.0080 1.00 0.00 11.00 0.00 0.88 0.00 110.00
GGBS 428 0 1.6000 0.0830 3.00 684.8 0.00 35.52 0.00 1284.00 0.00
Binder
Portlandcement
0 283 5.5000 0.9300 5.00 0 1556.50 0.00 263.19 0.00 1415.00
SHf 23.5 0 3.0000 0.0150 20.00 70.5 0.00 0.35 0.00 470.00 0.00
SSS 47 0 3.0000 0.0150 12.00 141 0.00 0.71 0.00 564.00 0.00
DistilledWater
164.5 0 0.0100 0.0008 2.00 1.645 0.00 0.13 0.00 329.00 0.00
Activatorsolution
Water 0 157 0.0100 0.0008 0.01 0 1.57 0.00 0.13 0.00 1.57
Sand 642 814 0.1500 0.0051 1.00 96.3 122.10 3.27 4.15 642.00 814.00Aggre-gates Coarse
Aggregate1070 1015 0.0830 0.0048 1.00 88.81 84.25 5.14 4.87 1070.00 1015.00
Processing 2375 2379 0.0140 0.0180 0.50 33.25 33.31 42.75 42.82 1187.50 1189.50Total for concrete 2375 2379 1116 1809 88 316 5547 4545
EE = Embodied energy, ECO2e = Embodied CO2 emitted, GGBS=Ground granulated blast furnace slag, SHf=Sodium hydroxide flakes,SSS=Sodium silicate solution, AS=Activator Solution (water for PPCC)
Table 4b—Benefits of geopolymer concrete (GPC) relative to Portland pozzolana cement concrete (PPCC)
GPC PPCC AdvGPC (%) Remarks
Compressive strength at 28 day, fc28, MPa 63 48 31 GPC is stronger
Embodied energy (EE) MJ/m3 1116 1809 -38 GPC needs lower energy
Embodied carbon dioxide emission (
ECO2e)
kgCO2e/m3 88 316 -72 GPC involves less emission of ‘green house gas’
(GHG)
Cost of per cubic meter (indicative) Rs/m3 5547 4545 22 GPC is costlier on unit volume basis
EE/fc28 MJ/MPa 18 38 -53 GPC needs less energy for unit strength
ECO2e/fc28 kgCO
2e/MPa 1 7 -79 GPC produces less GHG for unit strength
Cost/fc28 Rs/MPa 88 95 -7 GPC is economical on unit strength basis
8/9/2019 012- Sulphuric Resistant Geopolymer
http://slidepdf.com/reader/full/012-sulphuric-resistant-geopolymer 9/11
RAJAMANE et al.: GEOPOLYMER CONCRETE 365
The EEs of GPC and PPCC were 1116 and 1809
MJ/m3 (Table 4) and thus the GPC was 38% lower in
energy requirement (Fig. 4). The ECs of GPC and
PPCC were 88 and 316 kgCO2e/m3 and thus the GPC
was 72% lower in CO2 emission. Therefore, the GPCcan be considered as more ecofriendly. It may benoted here that the PPCC considered here itself had
28% fly ash and if the conventional concrete is made
of OPC only (which is often the case still in many
projects), the GPC would still look more
advantageous. Because of high cost of AAS, the GPCis found to be about 22% costlier, but, it had much
higher early strengths at 1 day and 7 day there by
offering many construction advantages which are not
accounted here in costing. Moreover, if the present
PPCC is modified and re-designed to possess same
strength as that of GPC at 28 day, the cost of PPCCwould be higher than the present estimate thereby
reducing the difference between the costs of the two
concretes.
However, if 28 day strength is taken as criterion,
the energy required to produce one MPa of concrete
strength is about 18 MJ/m3 only which is 53% less
than required for PPCC. Similarly, the CO2e emitted
to produce one MPa of strength is about 1 kg/m3 only
which is 79% less than that of PPCC (Table 4b, Fig. 4).
Thus, the GPC is ecologically superior to PPCC fromconsideration of energy required for strength also. It
may be concluded here that the GPC is alwaysadvantageous ecologically as compared to PPCC.
Ecological analysis of concretes presented in this
paper can be taken as only indicative in nature and
actual computations needs to consider manyparameters such as transportation costs, etc. It is
worthwhile to note here that geopolymer being a
relatively new binder, it becomes a necessity for
engineers to study the literature published by eminent
scientists before adopting the same in any practicalapplication36,54-56.
ConclusionsThe following conclusions can be drawn from the
study presented in this paper:
(i) It was seen that the geopolymer concrete(GPC) mix could be produced easily using
equipment similar to those available for
conventional cement concretes. GGBS, when
used as geopolymer source material, produced
geopolymer binder due to addition of sodium
hydroxide-silicate based activator solution.
The geopolymers formed in the reactions
produced high grade structural concretes by
self-curing mechanisms only. The strength
level achieved are much more than theminimum grade specified for “extreme”
exposure condition of IS 456-2000.(ii) The GPC is found to be more acid resistant,
since the specimens even after 90 days of
immersion in both 2% and 10% sulphuric acidsolutions, remained almost intact. In contrast,
the Portland pozzolana cement (PPC) based
PPCC specimens had deteriorated with very
obvious external damaged surfaces
accompanied by noticeable bulging. It may berecognised here that PPCC mix has both
pozzolanic fly ash and Portland cement as
binder and this concrete is reported to the
better than OPC based concretes. Therefore,GPC could be considered as superior to bothOPC and PPC concretes from the durability as
well as strength considerations.
(iii) The industrial by-product of GGBS based
GPC of the present study, was found to
possess much higher acid resistance when
measured in terms of loss of weight and
reduction in compressive strength on acid
attack, as compared to PPCC. The test data
presented in this paper confirms that the GPC
is a good candidate material of constructions
from both strength and durabilityconsiderations. It is to be noted here that the 1
day strength of 30 MPa recorded in GPC here
is actually indicative of GPC being a high
early strength concrete since this strength level
is generally very difficult to achieve in
Portland cement based conventional concretes.
The rate of strength development of GPC is
also higher since the ratio of 1 day strength to
28 day strength and also the ratio of 7day
strength to 28 day strength are both much
Fig. 4—Ecological advantages of GPC relative to PPCC
[100 * (PPCC – GPC)/PPCC]
8/9/2019 012- Sulphuric Resistant Geopolymer
http://slidepdf.com/reader/full/012-sulphuric-resistant-geopolymer 10/11
INDIAN J ENG. MATER. SCI., OCTOBER 2012366
higher than those observed for PPCCs. Thus, itis seen that the GPC offers many advantages in
actual constructions also.
(iv) Since the GPC does not have any Portlandcement, it can be considered as less energy
intensive (i.e., low ‘embodied energy’), incontrast, Portland cement based concrete is
very highly energy intensive material since
Portland cement is one of the very high
‘embodied energy’ which is reported to be
next only to aluminium and steel. Apart fromless energy intensiveness (actually very low
‘embodied energy’), the GPC utilises the
industrial by-product for producing the binding
system in concrete, therefore, GPC should be
considered as highly eco-friendly material of
construction.
AcknowledgementsThe cooperation and help received from the
scientific and technical staff including several student
project trainees of Advanced Materials Laboratory
(formerly Concrete Composites Laboratory), CSIR-
SERC in the preparation of this paper are gratefully
acknowledged.
References1 Shetty M S, Concrete Technology-Theory and Practice, (S C
Chand Company, New Delhi), 2006.2 Mehta P K & Monteiro P J M, Concrete: Microstructure,
Properties and Materials, 3rd ed, (McGraw-Hill, New York),2005.
3 Neville A M, Properties of concrete, 4th ed, (Addison-Wesley Longman Ltd.) 1995, p 844.
4 Hewlett P C, Lea's Chemistry of Cement and Concrete,(Butterworth-Heinemann, Technology & Engineering), 2003,p 1092.
5 Bakharev T, Sanjayan J G, & Chen Y B, Cem Concr Res,
33(10) (2003) 1607-1611.6 Davidovits J, J Therm Anal, 37 (1991) 1633-1656.7 Davidovits J, presented in IntWorkshop on Geopolymer
Cement and Concrete, Annamalai University,
Annamalainagar, 8-10 December 2010..
8
Cheng T W & Chiu J P, Miner Eng, 16(3) (2003) 205-210.9 Rangan B V & Hardjito D, Development and Properties of
Low-Calcium Fly Ash-based Geopolymer Concrete,
Research Report GC1, Faculty of Engineering, CurtinUniversity of Technology, Perth, 2005.
10
Rangan B V & Sumajouw M D J, Low-Calcium Fly Ash-
Based Geopolymer Concrete: Reinforced Beams and
Columns, Research Report GC3, Faculty of Engineering,Curtin University of Technology, Perth, 2006.
11
Rangan B V & Wallah S E, Low-Calcium Fly Ash-Based
Geopolymer Concrete Long-Term Properties, ResearchReport GC2, Faculty of Engineering, Curtin University ofTechnology, Perth, 2006.
12 Rangan B V, Fly ash-based geopolymer concrete, ResearchReport GC 4, Curtin. University of Technology, Perth,Australia, 2008.
13
Rajamane N P & Sabitha D, Studies on geo-polymer mortars
using fly ash and blast furnace slag powder , presented in IntCongress on Fly Ash, New Delhi, India, 2005.
14
Rajamane N P, Nataraja M C, Lakshmanan N & Ambily P S,GGBS based geopolymer concretes with and without fly ash ,
presented Nat Seminar on Engineered Concretes, 28-29March, Bangalore, 2007, 26-35.
15 Rajamane N P, Lakshmanan N & Nataraja M C, Civil Eng
Constr Rev, 22 (2) (2009) 70-77.
16 Rajamane N P, Nataraja M C, Lakshmanan N & Ambily P S, New Build Mater Constr World , 16(5) (2010) 242-247.
17
Rajamane N P, Nataraja M C, Lakshmanan N & Dattatreya JK, Indian Concrete J , 85(11) (2011) 11-14.
18
Rajamane N P, Nataraja M C, Lakshmanan N & Dattatreya JK, Int J 3R’s, 3(1) (2012) 378-388.
19 van Wazer John R, Inorg Macromolecules Rev, 1 (1970) 89.
20
Rahier H, Mele B V, Biesemans M, Wastiels J & Wu X, J Mater Sci, 31(1) (1996) 71-79.
21 Rahier H, Mele B V & Wastiels J, J Mater Sci, 31(1) (1996)80-85.
22
Rahier H, Simons W, Mele, B V & Biesemans M, J Mater
Sci, 32(9) (1997) 2237-2247.
23
Roy Della M, Cem Concr Res, 29(2) (1999) 249-254.
24 Palomo A & López dela Fuente J I, Cem Concr Res, 33(2)(2003) 281-288.
25 Palomo A & Palacios M, Cem Concr Res, 33(2) (2003) 289-295.
26
Torgal Fernando Pacheco, Joa˜o Castro-Gomes & Said Jalali,Constr Build Mater , 22(7) (2008) 1305-1314.
27 Torgal Fernando Pacheco, Joa˜o Castro-Gomes & Said Jalali,
Constr Build Mater , 22(7) (2008) 1315-1322.28 Krivenko P V, Alkaline cements, in Proc 1st Int ConfonAlkaline Cements, Concretes, edited by Krivenko P V,VIPOL Stock Company, Kiev, Ukraine, Vol 1 (1994)11-129.
29 Mallicoat S, Sarin P & Kriven W M, Novel, alkali-bonded,
ceramic filtration Membranes, Ceramic Engineering and
Science Proc, 26 (4) (2005) 37-41.
30
Sofi M, van Deventer J S J, Mendis P A & Lukey G C, J
Mater Sci, 42(9) (2007) 3107-3116.
31
Bao Y, Grutzeck M W & Jantzen C M, J Am Ceram Soc,88(12) (2005) 3287-3302.
32 Davidovits J, US Patent 4349386, http://www.freepatents-online.com/4349386.html, (1980).
33 Rahier H, Denayer J F & Mele B V, J Mater Sci, 38(14)
(2003) 3131-3136.34
Rostami H & Brendley W, Environ Sci & Technol, 37(15)
(2003) 3454-3457.
35
Glukhovsky V D, Soil silicates, Their Properties,
Technology and Manufacturing and Fields of Application,Doct Tech Sc. Degree thesis. Civil Engineering Institute,Kiev, Ukraine, (1965)
36 Provis J L & van Deventer J S J (Ed), Geopolymers:
Structures, processing, properties and industrial
applications, ISBN-13: 978 1 84569 449 4, (2009) 464.
37 Rajamane N P, Nataraja M C, Lakshmanan N & Dattatreya JK, Applicability of Acceptance Criteria of IS:456-2000 to
GGBS based Self Curing Geopolymer Concrete, Proc Nat
8/9/2019 012- Sulphuric Resistant Geopolymer
http://slidepdf.com/reader/full/012-sulphuric-resistant-geopolymer 11/11
RAJAMANE et al.: GEOPOLYMER CONCRETE 367
Conf on Advances in Materials and Structures(AMAS-2011), Pondicherry, 3-4 Feb 2011, 370-378.
38 Rajamane N P, Nataraja M C, Lakshmanan N & Dattatreya JK, Flexural Behaviour of Reinforced Geopolymer Concrete
Beams, Proc 7th Structural Engineering Convention SEC2010, Annamalai University, Annamalainagar, 8-10December 2010, 617-625.
39 Rajamane N P, Nataraja M C, Lakshmanan N & Dattatreya J
K, Pull –Out Tests for Strengths of Geopolymer Concretes,Proc Nat Conf on Advances in Materials and Structures(AMAS-2011, Pondicherry, 3-4 Feb 2011, 350-358.
40 Rajamane N P, Nataraja M C, & Lakshmanan N,
Geopolymer mortar-an ecofriendly zero-Portland cement
matrix for ferrocement , Proc Nat Conf on Ferrocement,Pune, 13-14 May 2011, 53-60.
41 Rajamane N P, Nataraja M C, Lakshmanan N, & Dattatreya J
K, Indian Concr J , 85(10) (2011) 21-26.42 Rajamane N P, Nataraja M C, Lakshmanan N & Dattatreya J
K , Int J 3R' , 2(2) (2011) 246-252.
43
Dinakar P, Babu K G & Manu Santhanam, Cem ConcrCompos, 30(10) (2008) 880-886.
44 Thokchom Suresh, Partha Ghosh, & Somnath Ghosh, Int J
Recent Trends Eng, 1(6) (2009) 36-40.45
Tognonvi Monique Tohoué, Julien Soro & Sylvie Rossignol,
New J Glass Ceram, 2(2) (2012) 85-90.
46 Sata Vanchai, Apha Sathonsaowaphak & Prinya
Chindaprasirt, Cem Concr Compos, 34(5) (2012) 700-708.
47 Sustainable concrete, ISBN 978-0-9584779-4-9 (Cement &
Concrete Institute, Midrand, South Africa), 2011, 37.
48
URL1, http://www.sustainableconcrete.org.uk/49 URL2, http://www.cnci.org.za/Uploads/CandCI_Footprint_
Report_V16.pdf
50 URL3, https://wiki.bath.ac.uk/display/ICE/Home+Page
51 BCA CSMA UKQAA, Embodied CO2 of UK cement,additions and combinations. Information Sheet P1, P2,November (2008).
52 Flower D J M & Sanjayan J G, Int J LCA, 12(5) (2007)282-288.
53 Hammond Geoff & Craig Jones, Inventory of Carbon &Energy (ICE), Version 2.0, Sustainable Energy Research
Team (SERT), Department of Mechanical Engineering,University of Bath, UK, 2011.
54
Davidovits J, Geopolymer Chemistry and Applications, 3rded, Institut Géopolymère, Saint-Quentin, France, 2011, 632.
55 Sindhunata, A conceptual model of geopolymerisation, Ph D
Thesis, The University of Melbourne Melbourne (2006).
56 Shi Caijun, Della Roy & Pavel Krivenko, Alkali-Activated
Cements and Concretes, (Taylor & Francis), 2006, 392.