Evaluating the Strength and Durability Properties of Geopolymer-

Stabilized Soft Soil for Deep Mixing Applications

ZAHRAA TAWFIQ NAEEM1, AHMED RAAD AL-ADHADH2, THAIR HUMMOD WAZI3

1Department of Civil Engineering,

College of Engineering, Al-Muthanna University,

Al- Muthanna,

IRAQ

2Department of Civil Engineering,

College of Engineering, Al-Muthanna University,

Al- Muthanna,

IRAQ

3Al Muthanna Government,

Muthanna Water Directorate,

IRAQ

Abstract: - Soft soil poses serious challenges and is unsuitable for engineering projects because of its

insufficient bearing capacity, low shear strength, and high compressibility. Deep soil mixing (DSM) is one of

the most popular methods of enhancing soft soil qualities, such as increased bearing capacity and reduced

settling, which are critical for building any structure. The environmental effects of creating binders such as

cement and lime make it crucial to identify alternative materials for geotechnical applications. This study

employed fly ash (class C) --based geopolymer to investigate its effectiveness as an environmentally friendly

substitute for cement for DSM applications. The experimental program included unconfined compressive

strength, flexure strength, and durability tests. The parameters in the study are binder content (10, 15, and 20%)

and activator/binder ratio (0.4, 0.6). Results revealed that UCS and flexural strength, GP-treated soil were in the

range of 0.9–5.3 and 0.8–1.5 MPa, respectively (depending on the ratio of fly ash and activator). These

strengths were even higher than those of cement-stabilized soil. The geopolymer-treated specimens exhibited

excellent endurance over the wetting-drying cycle, with a modest weight loss of less than 4.5%. A binder

dosage of more than 10% and an AC ratio of 0.6 were recommended to meet DSM application guidelines. The

current study concludes that employing a fly ash-geopolymer binder to stabilize soft soil is an effective

alternative to cement in DSM applications.

Key-Words: - Fly ash class C, wetting-drying test, UCS, DSM, geopolymer, Flexure, SEM.

Received: June 7, 2024. Revised: October 16, 2024. Accepted: November 15, 2024. Published: December 3, 2024.

1 Introduction

Soft soil is generally defined as having low

permeability, little compressibility, and significant

shear strength. It becomes necessary to stabilize it

when building structures over them. This can be

done using established physical or chemical

stabilization techniques to stabilize the treated soil

and transfer loads. Deep stabilization techniques

like electro-osmosis, grouting, stone columns,

preloading with vertical drains, and so forth must be

used if the soft soil deposits reach greater depths,

[1]. One of these methods is the deep soil mixing

(DSM) method, a cutting-edge method with various

global applications. To support low- to medium-

load structures, this technique essentially entails

installing soil binder columns-columns made of

mixed binder, either wet or dry—below the ground

surface with augers. These columns reinforce the

soft ground, enhancing its effectiveness by reducing

settlements and increasing bearing capacity, [1], [2].

The DSM approach has several advantages over

other deep stabilization systems, including ease of

use, a wide variety of applications, the ability to

place columns in various patterns such as the wall,

block, and grid, and significantly decreased sludge

removal during column installation.

WSEAS TRANSACTIONS on ENVIRONMENT and DEVELOPMENT

DOI: 10.37394/232015.2024.20.72

Zahraa Tawfiq Naeem,

Ahmed Raad Al-Adhadh, Thair Hummod Wazi

E-ISSN: 2224-3496

757

Volume 20, 2024

For DSM applications, traditional cementitious

binders, including cement, lime, and their mixes, are

frequently utilized as binders, [3], [4]. However,

because ordinary Portland cement (OPC) is

incompatible with current and future sustainability

and durability criteria, its usage for soil

stabilization, precast structural parts, and concrete

becomes dubious. In addition, the production of

cement and lime poses a serious environmental risk

due to its high carbon emissions. For instance, the

cement industry produces about seven percent of

CO2 emissions, [5]. Therefore, there is a need for

sustainable and cost-effective alternatives to cement.

Research on alkaline cement (which is also known

as alkaline cement, inorganic polymers, geo cement,

alkali-activated binders, and geopolymers) from the

last few decades validate these substances as a

suitable alternative for traditional cement because

they use industrial byproducts such as fly ash,

metakaolin, and so on, [6], [7] Alkali-activated

binder creates 60-80% less CO2 and requires 60%

less energy during manufacture than OPC, [6].

Geopolymers offer several

advantages, including high early strength, rapid

hardness, low shrinkage and permeability, high

resistance to chemical corrosion, and fire resistance,

[8]. There are certain drawbacks to geopolymer

materials, such as loss of workability owing to

alkaline solutions, the hazardous nature of the

ingredients utilized in these solutions and issues

such as the material's high alkalinity, [9]

Some recent research has been conducted on

using geopolymers as soil stabilizers, [10].

Geopolymer binder helped soil particles create a

more compact microstructure, improving soil's

volume stability and mechanical characteristics,

[11]. Fly ash is used as a geopolymer to replace

cement for soil stabilization, [12]. The study

discussed using activated fly ash to improve soft

soils. Cement and geopolymer samples have

equivalent unconfined compressive strength (UCS)

at curing 28 days. The properties of FA-based

geopolymer for high-plastic soil are investigated,

[13]. The UCS quickly increased by 400%.

Geopolymer stabilization enhances the resilience

modulus by increasing the activator dose, [14], [15].

The effects of metakaolin and alkali-activator on the

mechanical properties of the geopolymer-clay soil

are investigated by [16]. According to the

experimental results, the unconfined compression

strength of the geopolymer-improved soil improves

initially and then declines with metakaolin and

alkali-activator content. The geopolymer-improved

soil's strength performance and stabilizing effect

were investigated further by comparing it to pure

clay soil, lime soil, and regular Portland cement soil

using unconfined compression strength tests, direct

shear tests, and Brazilian split-cylinder tests. The

results demonstrate that the geopolymer-improved

soil has higher unconfined compression, shear, and

Brazilian splitting strength than the other three soil

types. [9] Investigated the application of activated

high calcium class C fly ash for sand soil

stabilization. The results showed that GP-treated

soil had higher UCS and flexural strength than

cement-stabilized soil. [14], studied the durability

and permanent deformation of several fly ash-

geopolymer mixtures. Despite varying permanent

deformation, soil with different fly ash amendments

exhibited equal resilience modulus. SEM images

were used to evaluate the interaction of industrial

waste and soil particles, the reaction of geopolymer

to temperature variations, and the geopolymer

proportion. The microstructure of soil-geopolymer

reveals that the strong bonding of calcium silicate

hydrate (C-S-H) and calcium aluminate hydrate (C-

A-H) is the explanation for the improved strength,

[17]. As a result, the geopolymer can be used for

both shallow-depth soil stabilization and deep soil

mixing applications, [18], [19]. Although fly ash

geopolymers are energy efficient and

environmentally friendly, they require a high

alkaline atmosphere and high curing temperatures

(60-90 °C) to activate reactions. This research

project aimed to enhance geopolymer

responsiveness by applying fly ash with high Ca

content at ambient temperature.

It has been discovered that geopolymers have

higher mechanical characteristics. However, nothing

is known regarding the long-term performance of

soil- geopolymers. The investigation does not

indicate the amount of geopolymer required to

produce the durability specified for OPC soils. One

of the most significant impediments to the

widespread adoption of this potential ground

improvement technique is a lack of comprehensive

study into the durability performance of soil-treated

geopolymers. This study aims to assess the

durability and strength of soft clay stabilized with

geopolymer, compare it to traditional OPC at high

binder dosages, and validate geopolymer

combinations in fulfilling DSM standards.

2 Experimental Program Materials

used Soil

The soil employed in this investigation is low plastic

clayey (Cl). The sample was obtained at a depth of

around 2 meters. Figure 1 shows the grain size

WSEAS TRANSACTIONS on ENVIRONMENT and DEVELOPMENT

DOI: 10.37394/232015.2024.20.72

Zahraa Tawfiq Naeem,

Ahmed Raad Al-Adhadh, Thair Hummod Wazi

E-ISSN: 2224-3496

758

Volume 20, 2024

distribution of the soil. Table 1 lists the soil

parameters, while Table 2 shows its chemical

composition.

3 Geopolymer (GP) Materials

GP binder employed in this investigation was a

combination of fly ash and a liquid sodium

activator. Fly ash (FA) was derived from coal-fired

power plants. Table 2 includes the chemical

compositions assessed using energy dispersive

spectroscopy (EDS). FA can be categorized as high

calcium CFA based on its chemical composition as

described in ASTM standard C618 as described in

ASTM standard C618, with Al2O3, SiO2, and Fe2O3

levels over 50% and Ca content greater than 20%.

The activator (hence known as AC) was a mixture

of sodium silicate (Na2SiO3) and sodium hydroxide

(NaOH). NaOH was immersed in distilled water for

no less than 24 hours with a molar concentration of

10 M before combining with Na2SiO3. To optimize

early strength and generate a massively alkaline

environment, the mass ratio of Na2SiO3/NaOH was

set to 2.0, [20].

4 Preparation of Samples and

Methodology

Samples were prepared using the same mixing

procedure throughout all tests. To ensure uniformity

and form the entire dry material, fly ash was mixed

with dry soil at a percentage replacement (by

weight) for five minutes. Subsequently, an activator

was created by combining sufficient NaOH and

Na2SiO3 for five minutes. To achieve the 10 Molar

concentration of the solution, NaOH was dissolved

in distilled water for at least 24 hours before mixing

with sodium silicate. It was diluted with more free

water before mixing with dry materials to create the

perfect moisture level for compaction. The final

mixture was compressed in layers with controlled

weight/thickness so that every sample could reach

the correct density. Cement-treated samples were

created by mixing cement paste (produced with a

water/cement ratio of 0.4) into the soil. Table 3

illustrates the testing schedule for the current

laboratory investigation.

The Unconfined Compressive Strength (UCS)

test is a fast and simple method to determine how

different factors, like the quantity and type of

stabilizer, affect the strength enhancement of treated

soil. The UCS tests were performed after a 28-day

cure time. The UCS test samples were created using

cylindrical tubes made of (PVC) measuring 50 mm

in diameter and 100 mm in height, providing a 2:1

height-to-diameter ratio as per (ASTM D1633-00,

2007), [21]. The test was conducted using a uniaxial

machine with a loading capacity of 50 kN and 0.1

mm per minute displacement rate.

For the flexural strength test, Treated samples

were prepared in rectangular molds with dimensions

of 50, 50, and 200 mm and tested after 28 days of

curing as per ASTM D1635/D1635M-19, [22]. The

following equation was used to determine the

samples' flexural strength:

   

 (1)

where fs is the flexural strength (MPa), l is the span

of the simple supports (mm), P is the max load (N),

b is the width of the sample (mm), and d is the

thickness of the sample (mm).

For durability tests, After 28 days of curing, the

specimens with 101.6 mm in diameter and 116.4

mm in height were immersed in water for 5 hours of

wetting before being oven-dried at 80 °C for 42

hours, completing one cycle of wetting and drying

according to ASTM D559-03, [23]. The durability

test involved 12 cycles of wetting and drying. The

weight of the samples was measured after each

wetting-drying cycle to calculate the mass change.

The specimens were brushed with a steel brush

across their whole surface before being weighed till

the cycle was complete. UCS tests were performed

on 45x90mm samples after 3, 6, 9, and 12 durability

cycles to determine soil residual strength. UCS

testing is not a standard technique for evaluating

durability; rather, it provides a signal for estimating

the deterioration caused by the treated materials.

Fig. 1: Particle size distribution curve of the soil

WSEAS TRANSACTIONS on ENVIRONMENT and DEVELOPMENT

DOI: 10.37394/232015.2024.20.72

Zahraa Tawfiq Naeem,

Ahmed Raad Al-Adhadh, Thair Hummod Wazi

E-ISSN: 2224-3496

759

Volume 20, 2024

Table 1. Soil properties

Table 2. Chemical compositions of the soil and FA using EDS

Table 3. Materials and testing program

Parameters

Binders

Geopolmer

Cement

Materials

Fly ash class C

OPC

Activator (AC)

Na2SiO3 and NaOH

Water

Binder content (%)

(10,15,20)

10,15,20

Activator/ fly ash or W/C ratio

0.4, 0.6

0.4

Test conducted

UCS, flexure, durability

5 Results and Discussion

5.1 Unconfined Compressive Strength

UCS

The findings are shown in Figure 2, where it is clear

that the specimens treated with GP had more UCS

than the specimens treated with cement at the same

dose. This is explained by the fact that, in contrast to

cement-treated mixes that only had pozzolanic

reactions, GP-treated mixes had higher levels of

both pozzolanic and polymeric processes. In other,

the GP- soil exhibits a higher rate of cementitious

product development than the soil- cement. These

results are consistent with the outcomes mentioned

by [9], [16], [19], [24].

The UCS significantly increased when the

activator at geopolymer-treated samples was

increased from 0.4 to 0.6. This is because an

enhancement in activator content caused an increase

in the leaching processes of aluminum and silicon

from the fly ash's amorphous phase.

Due to an increase in pH. This, consequently,

increased the formation of cementitious products

between the soil particles, such as N-A-S-H and C-

A-S-H, and, as a result, strengthened the soil even

more.

The findings of the UCS test demonstrate that

samples treated with 10% fly ash content and an AC

ratio of 0.4 could only satisfy the minimal UCS

threshold of 1.034 Mpa for DSM applications. As a

result, samples treated with 10% fly ash and Ac =

0.4 were not accepted for further testing.

Fig. 2: UCS for mixtures with various geopolymer

(GP) binder content and activator (AC) ratios

GP- AC 0.4 GP- AC 0.6 cement

UCS (Mpa)

10%

binder

15%

binder

Soil property

Standard

Value

Liquid Limit (LL), %

ASTM D 4318

46.3

Plastic Limit (PL), %

22.2

Plasticity index, %

24.1

Sand content, %

ASTM D 422

Clay content, %

40. 9

Silt content, %

30.9

Soil classification

ASTM D 2487

Optimum moisture content, %

ASTMD 1557

12.1

Max dry density (gm/cm³)

1.82

UCS (MPa)

ASTM D1633-00

0.189

Element

Na2O

MgO

Al2O3

SiO3

K2O

CaO

Fe2O3

other

soil

2.77

8.1

16.89

29.03

5.1

6.65

12.4

19.06

Fly ash

2.02

3.2

19.16

37.08

1.9

25.13

4.09

7.42

WSEAS TRANSACTIONS on ENVIRONMENT and DEVELOPMENT

DOI: 10.37394/232015.2024.20.72

Zahraa Tawfiq Naeem,

Ahmed Raad Al-Adhadh, Thair Hummod Wazi

E-ISSN: 2224-3496

760

Volume 20, 2024

6 Modulus of Elasticity

The stiffness of the specimens treated with GP and

OPC was determined using Secant Modulus (E50), a

stress-to-strain ratio referred to as Young's Modulus

at 50% UCS. The E50 values for all treated samples

follow the same trend as the UCS, as shown in

Figure 3. The relationship between the treated

specimens' UCS and E50 in this study is seen in

Figure 4. It demonstrates a correlation of E50 =

167*UCS for specimens treated with GP and E50 =

184*UCS for specimens treated with cement; these

values are in good accord with the range proposed

by earlier researchers [19], [25], [26]. [19], results

reveal a correlation of E50 = 164*UCS for GP-

treated specimens and E50 = 187*UCS for cement-

treated specimens.

Fig. 3: E50 for mixtures with various binder content

Fig. 4: Variation of E50 with UCS for soil-treated

mixes

7 Flexural Strength (fs)

After 28 days of curing, rectangular beam

specimens treated with 10, 15%, and 20% binder

contents were tested for flexural strength at AC

ratios of 0.4 and 0.6 (except for FA10%, AC 0.4).

Figure 5 shows the results of the flexural strength

test. The relationship between fs values and

geopolymer content followed a pattern similar to

those of UCS values, with a rise in GP content

attributed to greater flexural strength.

When comparing the Fs of geopolymer and

cement-soil samples. Fs of GP samples exceeded

that of OPC-treated samples. When the beams were

subjected to flexural testing, the top and lower

sections sustained compressive and tensile stresses,

respectively. Both tension and compression

contributed to the beam failure, while tensile stress

had a greater impact on the flexural failure [26]. A

previous study has demonstrated that when

geopolymer binders were used in concrete, they had

both higher and lower flexural strength than cement,

depending on the composition and ratio of source

materials, [27]. Cement-stabilized mixtures had

lower flexural strength than geopolymer-stabilized

mixtures, implying that they had lower tensile

strength.

Fig. 5: Flexural strength values for mixtures with

different GP binder and cement

8 Durability

As part of the durability assessment process, the

specimens treated with cement and geopolymer

underwent wetting and drying cycles to determine

the mass loss and strength loss of each treatment.

Mass loss

The mass loss (%) of the stabilized samples exposed

to the w-d cycles is shown in Figure 6. Figure 6

shows that the samples underwent only a slight

weight loss of less than 4.5% during the 12 wetting-

drying durability cycles. The geopolymer gel that

holds the soil particles together is comparatively

strong since the mass loss was not significant.

100

200

300

400

500

600

700

800

900

1000

GP- AC 0.4 GP- AC 0.6 cement

E 50 (Mpa)

e50 10%

binder

e50 15%

binder

E50= 167 UCS

R² = 0.9828

E50= 184 UCS

R² = 0.923

100

200

300

400

500

600

700

800

900

1000

0 2 4 6

E50, Mpa

UCS, Mpa

0,2

0,4

0,6

0,8

1,2

1,4

1,6

1,8

GP- AC 0.4 GP- AC 0.6 Cement

Flexure strength, Mpa

10%

binder

15%

binder

WSEAS TRANSACTIONS on ENVIRONMENT and DEVELOPMENT

DOI: 10.37394/232015.2024.20.72

Zahraa Tawfiq Naeem,

Ahmed Raad Al-Adhadh, Thair Hummod Wazi

E-ISSN: 2224-3496

761

Volume 20, 2024

Regarding mixtures treated with cement, The

durability test was not passed by soil treated with

10% cement. As per ASTM D559, soil cement that

exhibits a mass change of more than 10% is deemed

unsuitable for the durability test. The GP-treated

mixes showed better endurance in terms of mass

loss than the cement-treated ones. The findings

indicate that soft soil treated with a geopolymer

binder based on fly ash can pass both wet and dry

durability tests.

9 Strength Loss

UCS testing was achieved on samples treated with

cement and geopolymer after 3, 6, 9, and 12

durability cycles to investigate strength deterioration

for wetting-drying processes of survived treated soil

(Figure 7).

Fig. 6: Wetting-drying changes in mass after twelve

cycles for geopolymer-treated soil and cement-soil

Fig. 7: Effect of wetting-drying cycles on UCS

values of soil-geopolymer and soil cement mixtures

After 12 cycles, a deterioration tendency was

identified for geopolymer-soil, with an overall value

of 23% at the sample with fly ash content of 15%

and an activator of 0.4. While the strength increased

in the third cycle, there was a slight deterioration in

other geopolymer samples. This may suggest that

the high temperatures of the durability drying cycle

accelerate the geopolymerization and the

corresponding gel formation/hardening of the soil,

which is then followed by a cumulative effect of the

durability cycle that degrades the stabilized soil

structure. It should be illustrious that the

geopolymerization and subsequent strength growth

are accelerated by heat curing, [28]. The alkali

activation succeeded in forming denser and less

porous/permeable materials, reducing the possibility

of water absorption and subsequent sample

deterioration owing to shrinkage and swelling

caused by wetting–drying cycles. According to

Figure 7, all of the GP-treated specimens met the

criterion for a minimum UCS of 1.034 MPa. Thus,

based on the durability results, the GP-treated

specimens were shown to be resistant to wetting and

drying in terms of mass loss and residual strength.

10 Microstructure

To further understand the mechanism of geopolymer

strength growth, the microstructure texture of

geopolymer-treated soil was examined using

scanning electron microscopy (SEM).

The composition of the FA-geopolymer is

principally determined by the dissolution of

aluminum silicate in fly ash by alkaline solutions

generated by polycondensation. The geopolymer

product is created by leaching Si4+ and AL3+ from

activator and fly ash reactions, solidifying over time

and cementing soil particles. SEM examination

reveals the degree of geopolymerization by

identifying etching on FA surfaces (Figure 8).

Where the geopolymerization reaction is indicated

by the cementitious product offerings on the fly ash

surfaces by silica and aluminum decomposition, the

etched holes in FA surfaces are often filled with

cementitious products and tiny particles, resulting in

a compact matrix.

GP-…

Cem…

10%

binder

15%

binder

20%

binder

4,2 3,8

3,87

32,87

10,2

7,2

2,9

GP- AC 0.4

mass loss (%)

WSEAS TRANSACTIONS on ENVIRONMENT and DEVELOPMENT

DOI: 10.37394/232015.2024.20.72

Zahraa Tawfiq Naeem,

Ahmed Raad Al-Adhadh, Thair Hummod Wazi

E-ISSN: 2224-3496

762

Volume 20, 2024

Fig. 8: SEM analysis for soil-geopolymer mixtures

11 Conclusions

The original motivation for the research comes from

the following points:

1. As civilization advances and soft soils become

more common, soil stabilization becomes

increasingly important.

2. The need to look for environmentally friendly

and sustainable alternatives to traditional soil

stabilization materials (e.g., OPC and lime), as

evidenced by the high carbon footprint and

other negative environmental effects associated

with sourcing and overexploiting non-renewable

raw materials.

3. More research is needed to determine the most

effective amount of geopolymer components for

stabilizing soft soils and improving their

mechanical and durability properties.

4. Solutions must address various practical issues

with geopolymers, such as processing

temperature and high content, which limit their

use in the field.

This research has focused on using fly ash with

a high calcium concentration (high-calcium Class C

fly ash) to increase the reactivity of the geopolymer

and maintain efficient ambient temperature curing.

Strength and durability tests were conducted on

mixtures treated with cement and geopolymer to

determine the effectiveness of this stabilizing

approach for soft soils. This paper reports on the

outcomes of the experimental study. A comparison

was also made between the effectiveness of GP-

treated and cement-treated specimens under

compression, flexure, and wetting-drying cycles.

The current experimental inquiry yielded the

following conclusions:

1. In unconfined compression, the GP-treated

specimens displayed more UCS than the

cement-treated specimens with the same dose,

which could reflect the combined effect of GP's

geopolymeric and pozzolanic processes.

2. E50 values for all treated samples show a

similar pattern to the UCS. GP-treated samples

had a lower E50 than cement-treated samples at

the same UCS, indicating they were less brittle.

There was significant agreement between the

correlation established by previous studies and

the anticipated relationship between E50 and

UCS of treated specimens in this study.

3. The improvement in flexural strength values

follows the same trajectory as the increase in

compressive strength. The flexural strength of

the GP-treated soil was found to be between 0.6

and 1.5 MPa, even greater than those of the

OPC-stabilized soil.

4. The geopolymer samples displayed high

durability. The treated samples were described

successfully, mainly bypassing 12 wetting-

drying cycles and a weight change of less than

4.5% with some residual strength.

The findings above suggest that fly ash class C-

based geopolymer stabilization can be a more

effective method for treating soft soils than cement

stabilization. This makes the use of FAC-

geopolymer-based stabilizers a sustainable

alternative for deep soil mixing applications.

12 Proposed Area for Future Research

Future research on geopolymer-stabilized soils will

most likely focus on a few key areas to improve

their performance and broaden their uses. Among

the possible topics for more research are:

WSEAS TRANSACTIONS on ENVIRONMENT and DEVELOPMENT

DOI: 10.37394/232015.2024.20.72

Zahraa Tawfiq Naeem,

Ahmed Raad Al-Adhadh, Thair Hummod Wazi

E-ISSN: 2224-3496

763

Volume 20, 2024

1. Continued study to optimize soil geopolymer

mix design, including soil type selection,

geopolymer precursors, and activating solutions.

2. Investigating the utilization of alternative waste

or byproduct resources as additional

cementitious materials or geopolymer

precursors.

3. Long-term durability of soil geopolymers was

investigated under various environmental and

service circumstances, including chemical

exposure, high temperatures, and freeze-thaw

cycles.

4. Creating established rules and best practices for

the large-scale use of soil geopolymers in

diverse geotechnical and building projects.

Declaration of Generative AI and AI-assisted

Technologies in the Writing Process

The authors wrote, reviewed and edited the content

as needed and they have not utilised artificial

intelligence (AI) tools. The authors take full

responsibility for the content of the publication.

References:

[1] B. B. Broms, “Stabilization of soil with lime

columns,” in Foundation engineering

handbook, Springer, 1991, pp. 833–855.

[2] Puppala, Anand J., Raja Sekhar

Madhyannapu, Soheil Nazarian, Deren

Yuan, and Laureano R. Hoyos. Deep soil

mixing technology for mitigation of

pavement roughness. No. FHWA/TX-08/0-

5179-1. 2008.

[3] S. Pourakbar and B. K. Huat, “A review of

alternatives traditional cementitious binders

for engineering improvement of soils,”

International Journal of Geotechnical

Engineering, vol. 11, no. 2, pp. 206–216,

2017.

[4] G. P. Makusa, “Soil stabilization methods

and materials,” Lulea University of

Technology, 2012.

[5] S. Rios, C. Ramos, A. Viana da Fonseca, N.

Cruz, and C. Rodrigues, “Mechanical and

durability properties of a soil stabilised with

an alkali-activated cement,” European

Journal of Environmental and Civil

Engineering, vol. 23, no. 2, pp. 245–267,

2017, doi:

10.1080/19648189.2016.1275987.

[6] S. Rios, N. Cristelo, A. Viana da Fonseca,

and C. Ferreira, “Structural performance of

alkali-activated soil ash versus soil cement,”

Journal of Materials in Civil Engineering,

vol. 28, no. 2, p. 4015125, 2016.

[7] J. Davidovits, “Geopolymer Chemistry and

Applications. 2nd,” Institute Geopolymere,

France, 2008.

[8] J. Davidovits, “Geopolymers and

geopolymeric materials,” Journal of

thermal analysis, vol. 35, no. 2, pp. 429–

441, 1989.

[9] A. H. J. Al-Rkaby, N. A. Odeh, A. Sabih,

and H. Odah, “Geotechnical

characterization of sustainable geopolymer

improved soil,” J Mech Behav Mater, vol.

31, no. 1, pp. 484–491, 2022.

[10] J. Davidovits, “Properties of geopolymer

cements,” in First international conference

on alkaline cements and concretes, Kiev

State Technical University, Ukraine:

Scientific Research Institute on …, 1994,

pp. 131–149.

[11] M. Zhang, H. Guo, T. El-Korchi, G. Zhang,

and M. Tao, “Experimental feasibility study

of geopolymer as the next-generation soil

stabilizer,” Constr Build Mater, vol. 47, pp.

1468–1478, 2013.

[12] Cristelo N, Glendinning S, Fernandes L,

Pinto AT. Effects of alkaline-activated fly

ash and Portland cement on soft soil

stabilisation. Acta Geotechnica. 2013 Aug;

8: 395-405. doi: 10.1007/s11440-012-0200-

[13] B. Adhikari, M. J. Khattak, and S. Adhikari,

“Mechanical and durability characteristics

of flyash-based soil-geopolymer mixtures

for pavement base and subbase layers,”

International Journal of Pavement

Engineering, pp. 1–20, 2019.

[14] X. Kang, G.-C. Kang, K.-T. Chang, and L.

Ge, “Chemically stabilized soft clays for

road-base construction,” Journal of

Materials in Civil Engineering, vol. 27, no.

7, p. 4014199, 2015.

[15] A. Mohammadinia, A. Arulrajah, J.

Sanjayan, M. M. Disfani, M. Win Bo, and

S. Darmawan, “Stabilization of demolition

materials for pavement base/subbase

applications using fly ash and slag

geopolymers,” Journal of Materials in Civil

Engineering, vol. 28, no. 7, p. 4016033,

2016.

[16] S. Wang, Q. Xue, Y. Zhu, G. Li, Z. Wu, and

K. Zhao, “Experimental study on material

ratio and strength performance of

geopolymer-improved soil,” Constr Build

Mater, vol. 267, p. 120469, 2021.

WSEAS TRANSACTIONS on ENVIRONMENT and DEVELOPMENT

DOI: 10.37394/232015.2024.20.72

Zahraa Tawfiq Naeem,

Ahmed Raad Al-Adhadh, Thair Hummod Wazi

E-ISSN: 2224-3496

764

Volume 20, 2024

[17] C. Teerawattanasuk and P. Voottipruex,

“Comparison between cement and fly ash

geopolymer for stabilized marginal lateritic

soil as road material,” International Journal

of Pavement Engineering, vol. 20, no. 11,

pp. 1264–1274, 2019, doi:

10.1080/10298436.2017.1402593.

[18] Abdullah, Hayder Hasan. "An experimental

investigation on stabilisation of clay soils

with fly-ash based geopolymer." PhD diss.,

Curtin University, 2020.

[19] V. Bhavita Chowdary, V. Ramanamurty,

and R. J. Pillai, “Experimental evaluation of

strength and durability characteristics of

geopolymer stabilised soft soil for deep

mixing applications,” Innovative

Infrastructure Solutions, vol. 6, no. 1, 2021,

doi: 10.1007/s41062-020-00407-7.

[20] N. A. Odeh and A. H. J. Al-Rkaby,

“Strength, Durability, and Microstructures

characterization of sustainable geopolymer

improved clayey soil,” Case Studies in

Construction Materials, p. e00988, 2022.

[21] ASTM International, “ASTM D1633 -

00(2007) Standard Test Methods for

Compressive Strength of Molded Soil-

Cement Cylinders,” ASTM international,

West Conshohocken, PA, USA, pp. 1–15,

2007.

[22] A. D. 1635/D1635M-19, “ASTM

D1635/D1635M-19 (2019) Standard test

method for flexural strength of soil-cement

using simple beam with third-point loading.

ASTM International, West Conshohocken,”

2019.

[23] ASTM International, “ASTM D 559-03 —

Standard test methods for wetting and

drying compacted soil-cement mixtures,”

pp. 1–7, 2003.

[24] H. H. Abdullah, M. A. Shahin, and P.

Sarker, “Use of Fly-Ash Geopolymer

Incorporating Ground Granulated Slag for

Stabilisation of Kaolin Clay Cured at

Ambient Temperature,” Geotechnical and

Geological Engineering, vol. 37, no. 2, pp.

721–740, 2019, doi: 10.1007/s10706-018-

0644-2.

[25] A. Arulrajah, M. Yaghoubi, M. M. Disfani,

S. Horpibulsuk, M. W. Bo, and M. Leong,

“Evaluation of fly ash-and slag-based

geopolymers for the improvement of a soft

marine clay by deep soil mixing,” Soils and

foundations, vol. 58, no. 6, pp. 1358–1370,

2018.

[26] G. A. Lorenzo and D. T. Bergado,

“Fundamental characteristics of cement-

admixed clay in deep mixing,” Journal of

materials in civil engineering, vol. 18, no. 2,

pp. 161–174, 2006.

[27] P. Nath and P. K. Sarker, “Flexural strength

and elastic modulus of ambient-cured

blended low-calcium fly ash geopolymer

concrete,” Constr Build Mater, vol. 130, pp.

22–31, 2017.

[28] I. García-Lodeiro, A. y Palomo, and A.

Fernández-Jiménez, “Alkali–aggregate

reaction in activated fly ash systems,” Cem

Concr Res, vol. 37, no. 2, pp. 175–183,

2007.

Contribution of Individual Authors to the

Creation of a Scientific Article (Ghostwriting

Policy)

The authors equally contributed to the present

research at all stages, from formulating the problem

to the final findings and solution.

Sources of Funding for Research Presented in a

Scientific Article or Scientific Article Itself

No funding was received to conduct this study.

Conflict of Interest

The authors have no conflicts of interest to declare.

Creative Commons Attribution License 4.0

(Attribution 4.0 International, CC BY 4.0)

This article is published under the terms of the

Creative Commons Attribution License 4.0

https://creativecommons.org/licenses/by/4.0/deed.en

_US

WSEAS TRANSACTIONS on ENVIRONMENT and DEVELOPMENT

DOI: 10.37394/232015.2024.20.72

Zahraa Tawfiq Naeem,

Ahmed Raad Al-Adhadh, Thair Hummod Wazi

E-ISSN: 2224-3496

765

Volume 20, 2024