Post on 07-Nov-2014
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GEOPOLYMERGEOPOLYMER
The term “geopolymer” was firstly applied to describe a family of
alkaline Aluminosilicate binders formed by the alkali activation of
alumino silicate minerals.
Geopolymer technology was introduced by Prof: Joseph Davidovits Joseph Davidovits
in 1978.
The formation of geopolymeric materials is the result of a complicated
heterogeneous chemical reaction occurring between Al-Si materials
and strongly alkaline silicate solutions.
Constituents of Geopolymer ConcreteConstituents of Geopolymer Concrete
Source materials
Materials which are rich in aluminum and silica can be used as source
material.
Ex: Fly ash, GGBS, Silica fumes, Rice husk ash etc..
Alkaline liquids
The most commonly used alkaline liquids are combinations of
sodium hydroxide with sodium silicate or potassium hydroxide with
potassium silicate.
GEOPOLYMER CONCRETEGEOPOLYMER CONCRETE
The oxides of silicon and aluminium present in the source material
reacts with alkaline liquids to form Geopolymer paste which binds
the coarse and fine aggregate to form Geopolymer concrete.
In present experimental work, Geopolymer concrete prepared by
using fly ash and GGBS as source material
Alkaline solution prepared by using Sodium hydroxide flakes and
sodium silicate solution (14M).
GEOPOLYMERIZATIONGEOPOLYMERIZATION
Geopolymerization can transfer large scale alumino-silicate wastes into value-
added geopolymeric products with sound mechanical strength and high acid,
fire and bacterial resistance
The average density of fly ash-based geopolymer concrete is similar to
that of OPC concrete.(Hardjito & Rangan B.V.)
The slump increases with increase in water content (Hardjito &
Rangan B.V.)
Higher the mixing time (up to 20 minutes) higher would be the
compressive strength. (Hardjito and Rangan.B.V)
The effective curing period of 24hours with temperature of 60°C
produces higher compressive strength of geopolymer concrete. The
temperature beyond the 60° C wouldn't find any significant increase in
strength. (Hardjito & Rangan B.V.)
General Properties of Geopolymer concrete
Alkali-activated fly ash mortars, regardless of the type of activator
used, are generally more durable than OPC mortars (P. Chindaprasirt;
T. Chareerat; S. Hatanaka; and T. CaoIn)
The optimal temperature duration of curing at 65°C for GPC was 20
hours beyond which the strength increase was marginal. (Ranganath,
R.V., and Mohammed Saleh)
The ratio of sodium silicate solution to sodium hydroxide solution
was varied from 0.5 to 4.5. The maximum strength was obtained
when the ratio was 2.5 at one, three and seven days. (Ranganath,
R.V., and Mohammed Saleh)
The Poisson’s ratio of fly ash-based geopolymer concrete with
compressive strength in the range of 20 to 35 MPa falls between 0.12
and 0.25. These values are similar to those of OPC concrete. (Uma.K,
Anuradha.R and Venkatasubramani.R )
The indirect tensile strength of fly ash-based geopolymer concrete is a
fraction of the compressive strength, as in the case of Portland cement
concrete. (M. D.J. Sumajouw and B. V. Rangan)
As the longitudinal tensile reinforcement ratio increased, the flexural
capacity of the beams increased significantly. (Sumajouw &
Rangan.B.V).
The flexural property and crack pattern is similar to portland cement
concrete (Sumajouw & Rangan.B.V).
Structural properties of Geopolymer concrete
The crack patterns and failure modes observed for RGPC beams
were found to be similar to the RPCC beams. The total number of
the flexural cracks developed was almost same for all the beams.
(Dattatreya, Rajamane, Sabitha, Ambily, and M.C. Nataraja)
The crack widths, crack spacing and no. of cracks were comparable
for both RPCC and RGPC beams. (Dattatreya, Rajamane, Sabitha,
Ambily, and M.C. Nataraja)
The measured deflections of beams and the predicted deflections
using ANSYS 12.0 show fair agreement. (Uma.K, Anuradha.R and
Venkatasubramani.R )
AIM OF THE RESEARCHAIM OF THE RESEARCH
The present study deals with the preparation of geopolymer concrete
using fly ash and GGBS.
To study the influence of binder content on compressive strength,
density & workability of GPC.
To study the optimum usage of GGBS along with fly ash to develop
GPC
To determine the compressive strength of GPC cubes and selecting the
value of optimum fck
Based on the above results the study was conducted on reinforced
geopolymer concrete beam for the optimum mix.
OBJECTIVE OF THE RESEARCHOBJECTIVE OF THE RESEARCH
Casting of geopolymer concrete cubes, cylinders and prisms for the optimum value of fck
Testing for compressive strength, split tensile strength &flexural strength from cubes, cylinders and prisms specimens.
Casting of six simply supported RGPC beams for the optimum value with longitudinal tensile reinforcement as the variable.
To study the flexural behaviour, crack patterns, surface strain measurement and load deflection behaviour of reinforced geopolymer concrete beams under two point loading.
Materials required for developing GPC
Fly ash
GGBS
Coarse aggregate
Fine aggregate
Sodium hydroxide
Sodium silicate
Super plasticizer
Physical and chemical properties of fly ash Class F fly ash is used in this experiment is brought from RTPS Karnataka.
Sl No
Description ValuesRequirement as per 3812:2003
Physical property
1 Specific gravity 2.10 ------------
2Fineness (Blain’s air permeability) -m2/Kg
480 320
Chemical properties
3 SiO2 (% by mass) ) (Minimum) 61.98 35
4SiO2 + Al2O3 + Fe2O3 (% by mass)
(Minimum)94.24 70
5 Mg O (% by mass) (Maximum) 0.79 5
6Total sulphur as sulphur trioxide SO3
(% by mass) (Maximum)0.14 3
7 LOI (% by mass) (Maximum) 0.31 5
Physical and chemical composition of GGBS GGBS used for the experimental work is brought from RMC plant of ultratech
in Bangalore.
Sl No Description Values
Physical Composition
1 Specific gravity 2.10
2Fineness (Blain’s air permeability) m2/Kg
480
3Wet sieve analysis % retained on (45µ)
2.9 %
Sl No
Description Values
Chemical Composition
1 SiO2 (silicon dioxide) 33.78%
2 Al2O3 (Aluminum oxide) 17.08%
3 CaO (Calcium oxide) 39.87%
4 Mg O (Magnesium oxide) 7.10%
Coarse aggregate
The locally available crushed granite of 20mm down size was used
as the coarse aggregate.
Specific gravity of coarse aggregate = 2.64
Water absorption = 0.27 %
Fine aggregate
Locally available clean river sand was used as fine aggregate
Fineness modules of fine aggregate = 3.07
Specific gravity = 2.62
Fine aggregate test confirm to Zone-II as per IS :383-1970
Sodium hydroxide
For this experiment sodium hydroxide is used in the form of flakes.
Sodium silicate
Commercially available sodium silicate was used for the
experimental work with water content of 39.42% and specific
gravity of 1.61.
Super plasticizer
Conplast SP 430 (FOSROC chemicals)
GEOPOLYMER CONCRETE MIX DESIGN GEOPOLYMER CONCRETE MIX DESIGN
PARAMETERS PARAMETERS Wet density of geopolymer concrete- 2400 Kg/m3
Sodium silicate/ Sodium hydroxide- 2.5
Total water content- 140 Kg/m3
Water content in Sodium silicate- 39.42 %
Sodium hydroxide used- 14 Molar
Amount of binder used- 23 to 29%
Proportion of Coarse to fine aggregate =56%: 44%
DESIGN PARAMETERS VALUE UNIT Exp.. work
The wet density of geopolymer concrete 2400 Kg/m3 Constant
Ratio of Sodium silicate to Sodium Hydroxide
solution2.5 Constant Constant
The water content Chosen for Mix 140 Litres Constant
The water content in Sodium silicate 39.42% Percentage Constant
Amount of Binder used (Fly ash & GGBS) 23% to 29% Percentage Variable
Fly ash percentage 100% to 70% Percentage Variable
GGBS percentage 0% to 30% Percentage Variable
Coarse aggregate percentage 56% Percentage Constant
Fine aggregate percentage 44% Percentage Constant
Molarity of prepared Alkaline solution 14M Molarity Constant
Dosage of super plasticizer 2% Percentage Constant
Total water content - 140 lit/m3
Percentage variation of Fly ash and GGBS in the total binder content
29% Binder is used
Binder Content = 2098.26*0.29= 608.49 kg/m3
For 75% of Fly ash =0.75* 608.49 =456.37 kg/m3
For 25% of GGBS=0.25* 608.49 =152.12 kg/m3
The proportion of coarse aggregate to fine aggregate based on least void content
Therefore
Coarse aggregate = 0.56*1490= 834.4 kg/m3
Fine aggregate = 0.44*1490 = 655.6 kg/m3
And also 2% of super plasticizer (Conplast SP 430) was used
The final proportions for one cubic meter of Geopolymer concrete
Particulars Fly ash GGBS C.A F.A NaoH Na2Sio3
Super plasticizer dosage
Dosage ml
Kg/m3 456.38 152.12 834.4 655.6 86.21 215.53 2% 153
Ratio 1 0.33 1.83 1.44 0.19 0.47
MIX DESIGN OF GEOPOLYMER CONCRETEMIX DESIGN OF GEOPOLYMER CONCRETE
Mix proportionsMix proportionsTotal Binder
content Kg/m3 Proportion of Binder Fly ash GGBSFine
AggregateCoarse
AggregateAlkali Solution(kg/m3)
23%
Fly ash GGBS Kg/m3 Kg/m3 Kg/m3 Kg/m3 NaOH Na2Sio3
100% 0% 482.6 0 710.89 904.77 86.21 215.5395% 05% 458.47 24.13 710.89 904.77 86.21 215.53
90% 10% 434.34 48.26 710.89 904.77 86.21 215.53
85% 15% 410.21 72.39 710.89 904.77 86.21 215.53
80% 20% 386.08 96.52 710.89 904.77 86.21 215.53
75% 25% 361.95 120.65 710.89 904.77 86.21 215.53
70% 30% 337.25 144.78 710.89 904.77 86.21 215.53
Geopolymer concrete 140 liter mix
Total Binder content Kg/m3 Proportion of Binder Fly ash GGBS
Fine Aggregate
Coarse Aggregate
Alkali Solution(kg/m3)
25%
Fly ash GGBS Kg/m3 Kg/m3 Kg/m3 Kg/m3 NaOH Na2Sio3
100% 0% 524.6 0 692.41 881.25 86.21 215.5395% 05% 498.37 26.23 692.41 881.25 86.21 215.53
90% 10% 472.14 52.46 692.41 881.25 86.21 215.53
85% 15% 445.91 78.69 692.41 881.25 86.21 215.53
80% 20% 419.68 104.92 692.41 881.25 86.21 215.53
75% 25% 393.45 131.15 692.41 881.25 86.21 215.53
70% 30% 367.22 157.38 692.41 881.25 86.21 215.53
Geopolymer concrete 140 liter mix
Total Binder content Kg/m3 Proportion of Binder Fly ash GGBS
Fine Aggregate
Coarse Aggregate
Alkali Solution(kg/m3)
27%
Fly ash GGBS Kg/m3 Kg/m3 Kg/m3 Kg/m3 NaOH Na2Sio3
100% 0% 566.5 0 673.97 857.79 86.21 215.53
95% 05% 538.175 28.325 673.97 857.79 86.21 215.53
90% 10% 509.85 56.65 673.97 857.79 86.21 215.53
85% 15% 481.525 84.975 673.97 857.79 86.21 215.53
80% 20% 453.2 113.3 673.97 857.79 86.21 215.53
75% 25% 424.875 141.625 673.97 857.79 86.21 215.53
70% 30% 396.55 169.95 673.97 857.79 86.21 215.53
Geopolymer concrete 140 liter mix
Total Binder content Kg/m3 Proportion of Binder Fly ash GGBS
Fine Aggregate
Coarse Aggregate
Alkali Solution(kg/m3)
29%
Fly ash GGBS Kg/m3 Kg/m3 Kg/m3 Kg/m3 NaOH Na2Sio3
100% 0% 608.49 0 655.50 834.27 86.21 215.53
95% 05% 578.066 30.425 655.50 834.27 86.21 215.53
90% 10% 547.641 60.85 655.50 834.27 86.21 215.53
85% 15% 517.217 91.274 655.50 834.27 86.21 215.53
80% 20% 486.792 121.698 655.50 834.27 86.21 215.53
75% 25% 456.368 152.123 655.50 834.27 86.21 215.53
70% 30% 425.943 182.547 655.50 834.27 86.21 215.53
Geopolymer concrete 140 liter mix
PREPARATION OF GEOPOLYMER CONCRETEPREPARATION OF GEOPOLYMER CONCRETE
Preparation of Alkaline solution
Sodium hydroxide solution was added with sodium silicate solution
one day before the mixing of concrete.
Mixing
First aggregates and binder ( fly ash and GGBS) are mixed in tilting
drum mixer for about 3 minutes.
Then alkaline liquid is added to the dry mix and mixing is continued
for about 4 minutes.
TESTS ON FRESH GEOPOLYMER CONCRETETESTS ON FRESH GEOPOLYMER CONCRETE
Workability test
Slump test
Workability tests are conducted according to IS:1199-1959.
Workability test results for 140 lit mix Total Binder content
23%
Slumpmm
Total Binder content25%
Slumpmm
Proportion of Binder Proportion of Binder
Fly ash GGBS Fly ash GGBS
100% 0% 216 100% 0% 211
95% 05% 210 95% 05% 202
90% 10% 203 90% 10% 196
85% 15% 195 85% 15% 190
80% 20% 187 80% 20% 182
75% 25% 180 75% 25% 174
70% 30% 170 70% 30% 165
Total Binder content27%
Slumpmm
Total Binder content29%
Slumpmm
Proportion of Binder Proportion of Binder
Fly ash GGBS Fly ash GGBS
100% 0% 203 100% 0% 195
95% 05% 195 95% 05% 188
90% 10% 188 90% 10% 183
85% 15% 180 85% 15% 176
80% 20% 172 80% 20% 170
75% 25% 164 75% 25% 157
70% 30% 158 70% 30% 150
Slump test
Effect of 23% binder content on slump value Effect of 25% binder content on slump value
Effect of 27% binder content on slump value Effect of 29% binder content on slump value
Casting of specimens
Cube (150mmx150mmx150mm): 90 No’s
Prism (100mmx100mmx500mm) :9 No’s
Cylinder (150mmx300mm) :9 No’s
The fresh geopolymer concrete was cast into moulds immediately
after mixing.
Compaction is achieved by giving sixty manual strokes for each
layer by using tamping rod.
Rest period and CuringRest period and Curing
After casting, all the specimens were covered using plastic cover
to avoid the quick evaporation of water.
One days rest period was given for initial hardening of specimen.
After one day, specimens were kept in HACC (Hot air curing
chamber) and cured at 600 C for 24 hours.
After heat curing, specimens were kept in room temperature until
the date of testing.
Detailed arrangement of HACCDetailed arrangement of HACC
Circuit diagram of HACCCircuit diagram of HACC
The main features of HACCThe main features of HACC
Economical compared with Steam curing chamber.
Less maintenance.
Easy to carry, dismantle and install.
Specimen casting can done inside the chamber.
Chamber can place over the specimens.
Temperature source can place in any direction.
Uniformity in the temperature in all the direction.
Curing in HACC
Temperature checking in HACC Casting of specimens
Following tests were conducted on the harden geopolymer concrete
1. Compressive strength test
2. Split tensile strength test
3. Flexural strength test
Tests are conducted according to the IS: 516-1959
All the specimens were tested after 7th day from the date of casting the specimen.
Compression strength
Split tensile Strength
Flexural strength
Rest period- 1 Day
Binder content
Variation of fly ash to GGBS %DensityKg/m3
Load in KN
Compressive strength N/mm2
Average compressive
strength N/mm2Fly ash GGBS
23% 100 0
2328 640 27.9
29.792288 690 30.08
2297 720 31.39
23% 95 05
2316 950 41.42
39.672348 900 39.24
2308 880 38.37
23% 90 10
2308 1000 43.6
43.742316 970 42.29
2347 1040 45.34
23% 85 15
2270 1050 45.78
48.682334 1160 50.58
2310 1140 49.70
23% 80 20
2346 1180 51.45
53.342390 1290 56.24
2358 1200 52.32
23% 75 25
2374 1410 61.48
59.152344 1310 57.12
2345 1350 58.86
23% 70 30
2293 1100 47.96
51.302289 1180 51.45
2348 1250 54.50
23% binder content compressive strength
25% binder content compressive strength Rest period- 1 Day
Binder content
Variation of fly ash to GGBS %
Density
Kg/m3Load in KN
Compressive
strength N/mm2
Average
compressive
strength N/mm2Fly ash GGBS
25% 100 0
2297 740 32.26
34.182288 830 36.19
2285 780 34.08
25% 95 05
2265 1010 44.04
41.422256 820 35.75
2266 1070 46.65
25% 90 10
2286 1080 47.09
46.072278 1050 45.78
2331 1040 45.34
25% 85 15
2308 1220 53.19
51.162324 1200 52.32
2307 1100 47.96
25% 80 20
2335 1460 63.66
58.862330 1330 57.99
2315 1300 56.68
25% 75 25
2320 1340 58.42
63.812351 1560 68.02
2322 1490 64.96
25% 70 30
2375 1430 62.35
56.542327 1210 52.76
2354 1250 54.50
27% binder content compressive strength
Binder content Variation of fly ash to GGBS % Density
Kg/m3
Load in KN Compressive
strength N/mm2
Average compressive
strength N/mm2Fly ash GGBS
27% 100 0
2216 830 36.19
38.512297 900 39.24
2270 920 40.11
27% 95 05
2327 1100 47.96
45.492317 1050 45.78
2316 980 42.73
27% 90 10
2359 1070 46.65
49.562372 1260 54.94
2346 1080 47.09
27% 85 15
2267 1200 52.38
55.522281 1320 57.55
2276 1280 55.81
27% 80 20
2260 1360 59.30
62.672306 1520 66.27
2274 1430 62.35
27% 75 25
2262 1490 64.96
67.852297 1540 67.14
2334 1590 69.32
27% 70 30
2312 1390 60.60
60.172341 1480 64.53
2309 1270 55.37
Rest period- 1 Day
29% binder content compressive strength Rest period- 1 Day
Binder content
Variation of fly ash to GGBS %
Density
Kg/m3Load in KN
Compressive
strength N/mm2
Average
compressive
strength N/mm2Fly ash GGBS
29% 100 0
2320 1000 43.60
41.562319 900 39.24
2316 960 41.85
29% 95 05
2286 1170 51.01
50.282246 1100 47.96
2346 1190 51.88
29% 90 10
2259 1230 53.63
53.632260 1190 51.88
2282 1270 55.37
29% 85 15
2253 1410 61.48
57.412245 1220 53.19
2273 1320 57.55
29% 80 20
2335 1490 64.96
64.092302 1450 63.22
2296 1470 64.09
29% 75 25
2394 1620 70.63
69.472352 1560 68.02
2372 1600 69.76
29% 70 30
2356 1490 64.96
62.782351 1440 62.78
2320 1390 60.60
Variation of compressive strength for varying % of fly ash & GGBS
Effect of binder content on compressive strength
Based on the higher compressive strength 29% binder content i.e., (75:25) mix were selected for the split tensile strength and flexural strength test.
Total Binder 29%
Mix Casted
Load P
(kN)
Split tensile
strength
fct=2P/πld
(N/mm2)
Average split
tensile
strength
(N/mm2)
Fly ash GGBS
75% 25%Before casting
of beam
280 4.46
4.46260 4.14
300 4.77
75% 25%Casted along
with beam
250 3.98
4.30290 4.62
270 4.29
75% 25%Casted along
with beam
300 4.77
4.98310 4.93
330 5.25
Split tensile strength of cylindrical specimens
Flexural strength of prism specimens
Total Binder
29%Mix Casted
Load P
(kN)
Flexural strength
fcr=PL/bd2
(N/mm2)
Average
Flexural
strength
(N/mm2)Fly ash GGBS
75% 25%Before casting of
beam
15 6.0
5.3314 5.6
11 4.4
75% 25%Casted along
with beam
16 6.4
5.6012 4.8
14 5.6
75% 25%Casted along
with beam
16 6.4
5.7315 6.0
12 4.8
Based on the higher compressive strength i.e., optimum fck was selected
and same mix is used for casting beam specimens.
Geometry and reinforcement arrangement
BeamMix used
29%Binder
Beam Dimension
ReinforcementTensile
Reinforcement ratio (%)Compression Tension
B1,B2,B3 75:25 125X200X1300 2 # 8 2 # 10 0.75
B4,B5,B6 75:25 125X200X1300 2 # 8 2 # 12 1.08
Beam details
Form work for casting the beam specimen
Casting of beams Beams curing in HACC
Beams after curing in HACC
Schematic diagram for flexure test on beam
Photographic view of the test specimen before testing Demec gauge reading
Beam after testing
Crack patterns of -B1,B2 and B3 beams
Crack patterns of –B4,B5 and B6 beams
Cracking moment of test beams
Beam% of tensile
Reinforcement
compressive
strength fck
(N/mm2)
Modulus of rupture
(N/mm2)
fcr= 0.7√fck
Moment at first crack
Mc (kN-m)
Theoretical Cracking
moment
Mr=(fcr x
Igr/Yt)
(kN-m)
Ratio
Mc/Mr
B1 0.75 69.17 5.82 8.82 4.85 1.82
B2 0.75 69.17 5.82 9.2 4.85 1.89
B3 0.75 69.17 5.82 9.2 4.85 1.89
B4 1.08 69.17 5.82 9.2 4.85 1.89
B5 1.08 69.17 5.82 11.12 4.85 2.29
B6 1.08 69.17 5.82 11.50 4.85 2.37
Effect of tensile reinforcement ratio on the cracking moment of beams
Load versus mid span deflections of beam-B1
Load versus mid span deflections of beam-B2
Load versus mid span deflections of beam-B3
Load versus mid span deflections of beam-B4
Load versus mid span deflections of beam-B5
Load versus mid span deflections of beam-B6
Load versus mid span deflection of beams-B1,B2,B3
Beam% of tensile
Reinforcement
service load Ps
(kN)
Tested Mid span deflection at service load
δs(mm)
Maximum Deflection as
per IS :456:2000
δ
=le/250
(mm)
B1 0.75 72 4.602 4.6
B2 0.75 72 4.603 4.6
B3 0.75 84 4.550 4.6
Deflection of test beam
Load versus mid span deflection of beams-B4,B5,B6
Deflection of test beam
Beam% of tensile
Reinforcement
service load Ps
(kN)
Tested Mid span deflection at service load
δs(mm)
Maximum Deflection as
per IS :456:2000
δ
=le/250
(mm)
B4 1.08 92 4.578 4.6
B5 1.08 104 4.993 4.6
B6 1.08 100 5.030 4.6
Moment v/s Strain curve for Beam –B1
Moment v/s Strain curve for Beam –B2
Moment v/s Strain curve for Beam –B3
Moment v/s Strain curve for Beam –B4
Moment v/s Strain curve for Beam –B5
Moment v/s Strain curve for Beam –B6
Surface strain at service load of RGPC Beams
Beam designation
Working load Surface strain
Compression Tension
B1 72 0.00858 0.00372
B2 72 0.000260 0.001329
B3 84 0.000651 0.001103
B4 92 0.000411 0.001111
B5 104 0.000595 0.002042
B6 100 0.000742 0.001751
Flexural capacity of test Beams
Beam% of tensile
Reinforcement
compressive
strength fck
(N/mm2)
Mid span deflection at failure(mm)
Theoretical ultimate moment
Muc
Tested ultimate
moment Mut
B1,B2,B3 0.75 69.17 17.125 9.0 22.10
B4,B5,B6 1.08 69.17 16.780 12.74 28.49
Effect of Tensile reinforcement ratio on the ultimate moment of beams
The average density of geopolymer concrete is very similar to that
of normal conventional concrete.
The slump value of the fresh geopolymer concrete decreases with
the increase in total binder content of the mixture.
The experimental investigation have shown that using Fly ash
along with GGBS as source material, it is possible to produce
geopolymer concrete of compressive strengths (7 days) in the
range of 44-70 N/mm2.
GGBS as a source materials results in early initial strength and it
makes possible to de-mould the specimen’s very early. This is an
important applications of geopolymer concrete in the industry.
As the total binder content increases the compressive strength
also increases.
By using 25% GGBS (75% fly ash) in the total binder content
The early strength development of geopolymer concrete under
HACC conditions showed better strength properties.
Reinforced geopolymer concrete beams crack pattern shows
most of the cracks in the pure bending zone and all the beams
failed in flexure.
As per IS 456:2000 provision, the maximum strain at working
load should not exceed 0.0035. The maximum strain in all the
geopolymer concrete beams is well within this range.
The experimental crack load is much higher than the calculated
crack loads for all the six beams tested.
The flexural capacity of the beam increases with the increase in
longitudinal tensile reinforcement ratio, the tested ultimate
moment capacity of beams were found 2.4 times more than
theoretical ultimate moment capacity.
The experimental value of the ultimate load is much higher than
the calculated load for all the geopolymer concrete beams.
The further study on the geopolymer concrete can be focused on
trying with different water content of the mix. For finding the
optimum percentage of binder content.
A detailed cost analysis can be done to determine the financial
and environmental impact on the production of GPC.
Investigation has to be made with the use of different fibers in
reinforced geopolymer concrete.
The work has to be carried out on the long term properties of the
geopolymer concrete.
The geopolymer concrete containing proportionate mixture of
GGBS and fly ash has to be studied under ambient curing
conditions.
The study can be conducted using 100% GGBS for the
manufacture of geopolymer concrete under ambient curing
conditions which could be an important practical application.
Investigation has to be made on the shear behavior of
geopolymer concrete beams.
The study can be conducted on geopolymer concrete slabs.
References Hardjito, D. and Rangan, B.V. (2005). "Development and Properties of
low calcium fly ash based geopolymer concrete." Research report GC 1,
Curtin University of technology Perth, Australia.
Wallah, S.E., and Rangan, B.V. (2006). "Low calcium fly ash based
Geopolymer concrete: Long term properties." Research report GC2,
Curtin University of technology Perth, Australia.
Sumajouw, M.D.J., and Rangan, B.V. (2006). "Low calcium fly ash
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