Shear strength of compacted soils using geopolymer

Shear Strength Enhancement of
Compacted Soils Using Geopolymer
Soe Thiha
M5640010
A Thesis Submitted of the Requirement for the Degree of
Master of Engineering in Geotechnology
Suranaree University of Technology
25 May 2015

 Background and rationale
 Research objectives
 Scope and limitations
 Research methodology
 Literature review
 Sample preparation and collection
 Basic property test
 Compaction test
 Direct shear test
 Conclusion
 Future study
Outline

Back Ground and Rationale
www.kimberlayaustralia.com
www.panoramio.comwww.maquinaco.com.br
www.siemens.com www.indepent.ie

Back Ground and Rationale …
 To increase the strength of soil properties
 To decrease the permiability.
 To decrease soil slope failure.
www.texas.construction.comwww.ceer.iastate.edu.comwww.civilengineersforum.com www.globalroadtechniligy.com

Back Ground and Rationale …
Source
Material
 Cutting the world’s carbon.
 Low price of materials
 Better compressive
strength.
 Fire proof.
 Low permeability.
 Eco-friendly.
 Excellent properties within
both acid and salt
environments.
Advantages
ww.slideshare.net

Research Objective
 This study is to experimentally assess shear strength
enhancement of compacted soil using geopolymer in three-
ring shear testing device.
 The test results from the research will figure out how shear
strength of compacted soil samples (with water and with
geopolymer) between curing and non-curing under room
temperature (27  30 C).

Scope and Limitations
 Three types of soils are used.
 The soil samples are mixed with water and with geopolymer.
 Geopolymer is a mixture of fly ash and alkaline liquid with
equal amount of Na2Sio3 and NaOH.
 Na2Sio3 and NaOH are liquid state.
 The curing time has two stages as non-curing (for 0 day) and
curing (7 days) under room temperature.
 Normal stresses (n) are 0.4, 0.6, 0.8 and 1 MPa.

Research Methodology
Geopolymer
Basic Properties Tests Three-ring direct shear test
Sample Collection and Preparation
Literature Review
Resolving and Comparison
Discussions and Conclusion
Thesis Writing
Water

Literature Review
 Bagherzadeh-Khalkahali and Mirghasemi (2009) studied the
effects of particle size on macro and micro mechanical
behavior of coarse-grained soils. The results showed that the
internal friction angle the sample dilation increases with
growing the particle size.
 Bhat et al. (2003) researched the effect of shearing rate on
residual strength of kaolin clay and showed that hardly
increases in residual strength with increase shearing rate of
kaolin clay (0.233 - 0.586 mm/min).

Literature Review …
 Begrado et al. (2006) proposed that the internal frictional
angle of compacted clay is high at low normal stress and
decreases with increasing normal stress.
 Sonsakul et al. (2013) proposed the performance
assessment of three-ring compaction and direct shear testing
device and found that shear strength and MDD obtained
from three-ring mold are higher than ASTM standard mold.

 Davidovits (1978) coined the geopolymer which are new
material explored in many scientific fields and industrial
disciplines.
 Moayedi et al. (2011) reported that the effect of Na2SiO3 on
UCS of soft clay become less and less with longer curing
time. Temperature and curing period are significant in
influence of strength development.

 Sukmak et al. (2013) studied the geopolymerization
decreases with increasing moisture content due to the
reduction of alkaline liquid activator (L). At low moisture
content, low strength is obtained by inadequate L.
 Phummiphan et al. (2014) found that the optimum liquid
alkaline activators for lateritic soil – fly ash geopolymer
specimens decreases as NaOH solution increases. The fly
ash geopolymer could improve the mechanical properties of
the marginal soil.

 Chimoye (2014) studied the strength of soft Bangkok clay
improved by palm fuel ash geopolymer and found that higher
percentage of NaOH or palm fuel ash would give higher
compressive strength of Bangkok clay.
 Chanprasert et al. (2014) studied the strength and
microstructure of water treatment sludge-fly ash geopolymer.
The geopolymerization increases with heat duration and
weld clay and FA particles, and fill up the pore spaces..

Sample Collection and Preparation
 In this study, the soil samples are mixed together with
geopolymer blended raw materials, fly-ash and alkaline liquid
activator homogenously.
 Raw materials are collected as three types of soils:
 from Bang Nong Bong, Muang district, Nakhon
Ratchasima.
 from Bang Khen water treatment plan, Bangkok.
 from Dan Keen, Chock Chai district, Nakhon
Ratchasima.

Sample Collection and Preparation …
 Fly ash (FA) is a by-product of waste materials obtained from
Mae Moh Power Plant in Northern Thailand. According
ASTM D618, FA is classified as class F.
 Alkaline liquid is a mixture of Na2SiO3 and NaOH.
 Na2SiO3 is composed of 15.5% of NaOH, 32.75% of
SiO2 and water of 51.75% by weight.
 NaOH is 12.5 molars in solution.

Sample Collection and Preparation …
Fly-ash (FA) Sodium Hydroxide
(NaOH)
Sodium silicate
(Na2SiO3)
0 10 20 305 15 25 mm

Basic Property Test
 All basic property tests are followed ASTM standards and
procedures. They are included as follow as:
 Natural water content (ASTM D2216)
 Specific gravity (ASTM D854)
 Atterberg’s limit (ASTM D4318)
 Grain size analysis (ASTM D422)
 Unified soil classification system (ASTM D2487)

0
20
40
60
80
100
0.000.010.101.00
PercentPassing(%)
Particle Size (mm)
10.00
Silty Sand (SM)
Sludge (MH)
Clay (CH)
Basic Property Test …
Grain size distribution curve for three types of soils
0.075
4.75

Soil plasticity chart (Casagrande, 1942)
Silty sand (SM)
Passing (no.4) - 100%
LL - 12.7%
PI - 0.6%
Sludge (MH)
LL - 58%
PI - 25.5%
High plasticity clay (CH)
Passing (no.200) - 93.2%
LL - 68%
PI - 39.2%
U-line
PI =
0.9
(LL-8)
0 10 20 30 40 50 60 70 80 90 100
0
10
20
30
40
50
60
70
CL-ML
CL
or
OL
ML
or
OL
CH
or
OH
MH
or
OH
A-line
Liquid limit
Plasticityindex
0 10 20 305 15 25 mm
0 10 20 305 15 25 mm
0 10 20 305 15 25 mm

Table. Basic property test results of soil samples
Locations W (%) SG LL(%) PI(%) Soil Types
Ban Nong Bong 3.0 2.68 12.7 0.6 Silty sand (SM)
Dan Keen 10.5 2.67 68.0 39.2
High plasticity
clay (CH)
Bang Khen
Water Treatment
Plant
5.6 2.56 55.0 23.0
High plasticity
silt (MH)

Compaction Test
 Compaction is essential in many geotechnical applications to
improve the engineering properties of soils (Horpibulsuk et
al., 2013).
 Proctor (1933) proposed the compaction test for MDD and
OMC, known as Proctor compaction test.
 The proctor compaction test is easy to perform in the
laboratory due to workability of simple equipment.

Compaction Test …
 To find OMC and MDD of compacted soils, the empirical
equations are used as follow as:
 =
𝑊
𝑉 𝑚
(1)
 𝑑 =

1+
𝑤 (%)
100
(2)
Where  = moist unit weight, W = moist weight of soil,
Vm = moist volume of soil, d = dry unit weight,
w = water content of soil

Compaction Test …
Table1. Modified compaction test (ASTM D1557)
Method A Method B Method C
Material
≤ 20%
retained on
sieve No.4
>20% retained on
No.4 and ≤ 20%
retained on sieve 3/8”
>20% retained on
sieve 3/8” and <30%
retained on sieve 3/4”
Passing Sieve No.4 Sieve 3/8” Sieve 3/4”
Mold Dia. 4” 4” 6”
Layer No. 5 5 5
No. of
Blow/Layer
25 25 56

116.43
mm
Ø 114.3 mm
Ø 101.6 mm
Lower
Ring
Upper
Ring
457 mm
Standard mold and dropped hammer (ASTM D1557)
Compaction Test (cont.)

 Two types of samples are prepared as sample with water
and sample with geopolymer.
 For sample with water, soil sample and water are mixed
together as a normal way.
 For sample with geopolymer, fly ash and dry soil are mixed
together with a ratio FA/soil = 0.1 for five minutes. Then, the
mixture of liquid activator and water (LA/water = 0.1) is
added to soil-fly ash mixture and blending for next ten
minutes to be homogenous.
Compaction Test …

Mix design for test samples
Compaction Test …
Soil Water
Mixture with water
Sample with
Water
ASTM Compaction Test
OMC & MDD
FA/Soil = 0.1 AL/Water = 0.1
Mixture with geopolymer
Sample with
Geopolymer
(GP)

Compaction Test …
3
2
1
 Soil mixing process take a time for almost 15 minutes to get
homogenous mixture for compaction test sample.

Silty sand compaction results between sample with water and
sample with geopolymer
Sample with water
MDD – 1940 kg/m3
OMC – 7.8 %
Sample with geopolymer
MDD – 1925 kg/m3
OMC – 9.5 %
1780
1820
1860
1900
1940
1980
0 2 4 6 8 10 12 14
Water content (%)
Drydensity(kg/m3
)
Compaction Test …

High plasticity clay compaction results between sample with
water and sample with geopolymer
1400
1450
1500
1550
1600
1650
0 5 10 15 20 25 30 35
Water content (%)
Drydensity(kg/m3
)
Sample with water
MDD – 1634 kg/m3
OMC – 21 %
MDD – 1571 kg/m3
OMC – 19 %
Compaction Test …

Sludge compaction results between sample with water and
sample with geopolymer
900
1000
1100
1200
1300
1400
0 20 30 40 50
Water content (%)
Drydensity(kg/m3
)
6010
Sample with water
MDD – 1360 kg/m3
OMC – 26 %
MDD – 1250 kg/m3
OMC – 33 %
Compaction Test …

Soil Type
Compaction
Characteristic
OMC (%) MDD (kg/m3)
Silty sand
(SM)
Water 7.8 1940
Geopolymer 9.5 1925
High plasticity
clay (CH)
Water 21 1634
Geopolymer 19 1573
Sludge
(MH)
Water 26 1360
Geopolymer 32 1250
Table. Compaction parameters of three types of soils
Compaction Test …

Direct shear test
 Direct shear test is the oldest and simplest form in laboratory
and it is used to measure shear strength of soil (Das, 2010).
 Cohesion and friction are main parameters and they are
calculated by Mohr-Coulomb failure criterion.
f = c + n tan  (3)
Where f = shear strength in failure, n = normal stress,
c = cohesion of soil,  = friction angle of soil

 In this study, the shear strength is measured by using three-
ring direct shear test device.
 Three-ring direct shear test has an advantage to measure
shear strength after compaction without sample disturbance
due to changing mold (Sonsakul et al., 2013).
 Three-ring direct shear testing device has two portions:
 Three-ring compaction and shear mold
 Direct shear frame
Direct shear test …

Ø107.6 mm
Ø101.6 mm
50.8
mm
50.8
mm
50.8
mm
Upper ring
Middle ring
Lower ring
Three-ring compaction and shear mold

Method A
(ASTM D1557)
Three-ring Compaction
(Sonsakul et al., 2013)
Material
≤ 20% retained on
sieve No.4
-
Passing Sieve No.4
Under 10 mm
(max. grain size)
Mold Dia. 4” 4”
Layer No. 5 6
No. of Blow/Layer 25 27
Energy 2700 kN-m/m3 2700 kN-m/m3
Table. Comparison between ASTM and Three-ring method

Three-ring direct shear testing device
Vertical Dial
gauge
Normal load
Three-ring
mold
Shear force
load cell
Shear force
dial gauge
Hydraulic
hand pump

Side view of three-ring direct shear testing device
Normal
force
Shear
force

 Three-ring direct shear test is performed to measure the
shear strength of two kinds of soil samples under two curing
condition.
 As two kinds of soil samples,
 sample with water and sample with geopolymer
 As two curing conditions,
 non-curing (0 day) and curing (7 days)

ASTM Compaction Test
Three-ring Compaction
Curing (7 days) Non-curing (0 day)
Direct Shear Test
FA/Soil = 0.1 AL/Water = 0.1
Mixture with geopolymer
Sample with
Geopolymer
(GP)
Water
Mixture with water
Sample with
Water
Soil
OMC & MDD

 The test samples for curing are under ambient temperature
(27  30C) in laboratory for 7 days before shearing.
 For non-curing samples, they are sheared directly after
compacting in three-ring mold with the normal forces (0.4,
0.6, 0.8 and 1.0 MPa).
 The shear displacement rate is 1 mm/min (approximately) to
be obvious different outcome in shearing soil grains.

0.0
0.4
0.8
1.2
1.6
2.0
0 1 2 3 4 5 6 7 8
Shearstress(MPa)
Shear displacement (mm)
n = 1.0 MPa
0.8 MPa
0.6 MPa
0.4 MPa
n = 1.0 MPa
0.0
0.4
0.8
1.2
1.6
2.0
0 1 2 3 4 5 6 7 8
Shearstress(MPa)
0.8 MPa
0.6 MPa
0.4 MPa
0.0
0.4
0.8
1.2
1.6
2.0
0 1 2 3 4 5 6 7 8
Shearstress(MPa)
n = 1.0 MPa
0.8 MPa
0.6 MPa
0.4 MPa
0.0
0.4
0.8
1.2
1.6
2.0
0 1 2 3 4 5 6 7 8
Shearstress(MPa)
n = 1.0 MPa
0.8 MPa
0.6 MPa
0.4 MPa
Shear stresses and shear displacements of silty sand
Water (7 days)
Geopolymer (7 days)
Water (0 day)
Geopolymer (0 day)
Under
shear
rate
1mm/min

0.0
0.4
0.8
1.2
1.6
0 1 2 3 4 5 6 7 8
Shearstress(MPa)
n = 1.0 MPa
0.8 MPa
0.6 MPa
0.4 MPa
n = 1.0 MPa
0.0
0.4
0.8
1.2
1.6
0 2 4 6 8
Shearstress(MPa)
0.8 MPa
0.6 MPa
0.4 MPa
n = 1.0 MPa
0.8 MPa
0.6 MPa
0.4 MPa
0.0
0.4
0.8
1.2
1.6
0 2 4 6 8
Shearstress(MPa)
n = 1.0 MPa
0.8 MPa
0.6 MPa
0.4 MPa
0.0
0.4
0.8
1.2
1.6
0 2 4 6 8
Shearstress,MPa
Shear displacement, mm
Shear stresses and shear displacements of sludge
Water (7 days)
Geopolymer (7 days)
Water (0 day)
Geopolymer (0 day)
Under
shear
rate
1mm/min

0.0
0.4
0.8
1.2
1.6
0 2 4 6 8
Shearstress(MPa)
n = 1.0 MPa
0.8 MPa
0.6 MPa
0.4 MPa
n = 1.0 MPa
0.8 MPa
0.6 MPa
0.4 MPa
0.0
0.4
0.8
1.2
1.6
0 2 4 6 8
Shearstress(MPa)
0.0
0.4
0.8
1.2
1.6
0 2 4 6 8
Shearstress(MPa)
n = 1.0 MPa
0.8 MPa
0.6 MPa
0.4 MPa
0.0
0.4
0.8
1.2
1.6
0 2 4 6 8
Shearstress(MPa)
n = 1.0 MPa
0.8 MPa
0.6 MPa
0.4 MPa
Direct shear test (cont.)
Shear stresses and shear displacements of high plasticity clay
Water (7 days)
Geopolymer (7 days)
Water (0 day)
Geopolymer (0 day)
Under
shear
rate
1mm/min

Curing sample with geopolymer ( 7 days )
Non-curing sample with water ( 0 day )
Sludge
High Plasticity Clay
Silty Sand
Silty Sand Sludge
High Plasticity Clay
0 5 10 in 0 5 10 in 0 5 10 in
0 5 10 in 0 5 10 in 0 5 10 in

Soil
Type
Curing
time
(days)
Tested
samples with
Peak Residual
cp (MPa) p ( ) cr (MPa) r ( )
Silty
Sand
(SM)
0
Water 0.20 37.8 0.11 32.5
Geopolymer 0.22 43.3 0.12 37.3
7
Water 0.23 36.7 0.11 32.4
Geopolymer 0.59 51.4 0.13 45.1
Normal stress (MPa)
0.0
0.4
0.8
1.2
1.6
2.0
Residualshearsterength(MPa)
0.0 0.8 1.0 1.20.2 0.4 0.6
-
Res - G7
Res - G 0
Res - W 7
Res W0
Peak -G7
Peak -G0
Peak - W7
-Peak W0
0.2 0.4 0.6 0.8 1.0 1.2
Peakshearstrength(MPa)
Normal stress (MPa)
0.0
0.4
0.8
1.2
1.6
2.0

Soil
Type
Curing
time
(days)
Tested
samples with
Peak Residual
cp (MPa) p ( ) cr (MPa) r ( )
Sludge
(MH)
0
Water 0.32 25.0 0.25 23.8
Geopolymer 0.30 27.2 0.19 26.8
7
Water 0.37 25.4 0.21 23.3
Geopolymer 0.29 41.3 0.08 40.5
0.0 0.2 0.4 0.6 0.8 1.0 1.2
Normal stress (MPa)
Peak-G7
Peak-G0
Peak-W7
-Peak W0
0.0
0.4
0.8
1.2
1.6
2.0
0.0 0.2 0.4 0.6 0.8 1.0 1.2
Residualshearstrength(MPa)
Normal stress (MPa)
Res -G7
Res -G0
Res -W7
-Res W0
0.0
0.4
0.8
1.2
1.6
2.0

Soil
Type
Curing
time
(days)
Tested
samples with
Peak Residual
cp (MPa) p ( ) cr (MPa) r ( )
Clay
(CH)
0
Water 0.38 26.5 0.23 18.0
Geopolymer 0.17 32.4 0.21 26.2
7
Water 0.48 26.2 0.14 17.4
Geopolymer 0.66 41.8 0.24 25.2
0.0
0.4
0.8
1.2
1.6
2.0
0.0 0.2 0.4 0.6 0.8 1.0 1.2
Normal stress (MPa)
Peak -G7
Peak -G0
Peak - W7
-Peak W0
0.0 0.2 0.4 0.6 0.8 1.0 1.2
Residualshearstrength(MPa)
Normal stress (MPa)
Res -G7
Res -G0
Res -W7
-Res W0
0.0
0.4
0.8
1.2
1.6
2.0

Conclusions
 For silty sand and sludge, the soil samples with fly ash
geopolymer are increase optimum moisture content and
decrease maximum dry density.
 For high plasticity clay, fly ash geopolymer decreases
optimum moisture content corresponding with decrease of
maximum dry density.
 The compaction results point out that fly ash based
geopolymer cannot improve the maximum dry density.

Conclusions …
 The results of three-ring direct shear tests give higher
strengths in shearing when soil samples are mixed with
geopolymer and more higher strengths are attained through
the curing state.
 After compacting with fly ash geopolymer, the soils are
attained a harden state depending upon the curing period.

Conclusions …
 The more laboratory strengths based on curing period under
ambient temperature (27 – 30 C) point out that field strength
can be attained after construction because of chemical
reaction under ambient temperature in actual condition.
 The short time interval of mixing process of soil samples
reflects the advantages on field condition as in-situ mixing
process can be performed as fast as possible.

 Although clay soils are normally low internal friction angle,
the compacted condition with geopolymer gives higher
internal friction angle.
 The geopolymer can increase the shear strength of high
plasticity clay almost double.
Conclusions …

 The compacted soil mixed with geopolymer transform to
more brittle behavior in strain softening.
 Fly ash based geopolymer enhances the shear strength of
soils by increasing of cohesion and friction angle.
“ Soil improvement techniques using geopolymer can be applied
for strengthening the soil embankment, soil slope and earth dam
foundation.”
Conclusions …

Recommendations for future study
 The more soil specimens should be used to experimentally
perform three-ring direct shear test with various shearing
rates.
 The various ratios of geopolymer and raw materials might be
performed under high ambient temperature (>30 C) and
more curing periods (>7 days).

 The soil specimens may be under wet-dry cycle process
according to ASTM standard before shearing the sample in
direct shear device.
 Microscopic studies as SEM and XRD may be employed
when shearing for soil specimens with geopolymer.
Recommendations for future study …

Shear strength of compacted soils using geopolymer

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Viewers also liked

Viewers also liked (6)

Similar to Shear strength of compacted soils using geopolymer

Similar to Shear strength of compacted soils using geopolymer (20)

Recently uploaded

Recently uploaded (20)

Shear strength of compacted soils using geopolymer

Editor's Notes