1.4 soil stabilization technique mekanis dan kimiawi

8/11/2019 1.4 Soil Stabilization Technique Mekanis Dan Kimiawi

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Use of Locally Available Materialsand Stabilisation Technique


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Soil Stabilization

The soil stabilization means the improvement ofstability or bearing power of the soil by the use of

controlled compaction, proportioning and/or the

addition of suitable admixture or stabilizers.

Basic Principles of Soil Stabilization.

Evaluating the properties of given soil

Deciding the lacking property of soil and chooseeffective and economical method of soil stabilization

Designing the Stabilized soil mix for intended stability

and durability values


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Need for Soil Stabilization

Limited Financial Resources to Provide acomplete network Road System to buildin conventional method

Effective utilization of locally availablesoils and other suitable stabilizing agents.

Encouraging the use of IndustrialWastages in building low cost constructionof roads.


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Methods of Soil Stabilization

Mechanical StabilizationSoil Cement Stabilization

Soil Lime StabilizationSoil Bitumen Stabilization Lime Fly ash Stabilization Lime Fly ash Bound Macadam.


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Mechanical Stabilization

This method is suitable for low volume roads

i.e. Village roads in low rainfall areas.

This method involves the correctlyproportioning of aggregates and soil,

adequately compacted to get mechanically

stable layer

The Basic Principles of Mechanical Stabilization

are Correct Proportioning and Effective

Compaction


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Desirable Properties of Soil-

Aggregate Mix Adequate Strength

Incompressibility

Less Changes in Volume

Stability with Variation in water content

Good drainage, less frost Susceptibility

Ease of Compaction.


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Factors Affecting Mechanical

Stabilization

Mechanical Strength of aggregates

Gradation Properties of the Soil

Presence of Salts

Compaction


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Mechanical Strength

When the soil is used in small proportion to fill

up the voids the crushing strength of aggregatesis important

Gradation

A well graded aggregate soil mix results in a mix

with high dry density and stability values

Properties of soil

A mix with Plasticity Index, results poor stability

under soaking conditions. Hence it is desirable to

limit the plasticity index of the soil


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Presence of Chemicals Presence of Salts like Sulphates and mica

are undesirable

Presence of Calcium Chloride is Beneficial

Compaction

Effective Compaction is desirable to

produce high density and stability mix


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Soil Cement Stabilization

Soil Cement is an intimate mix of soil,

cement and water, compacted to form a

strong base course

Cement treated or cement modified soil

refers to the compacted mix when cement is

used in small proportions to impart some

strength Soil Cement can be used as a sub-base or

base course for all types of Pavements


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Factors affecting soil cement stabilization

Soil

Cement

Pulverisation and Mixing

Compaction

Curing

Additives


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Soil

THE PHYSICAL PROPERTIES

Particle Size Distribution

Clay content

Specific Surface

Liquid limit and Plasticity Index

Cement

A increase in cement content generally

causes increase in strength anddurability


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Pulverisation and Mixing Better the Pulverisation and degree of mixing,

higher is the strength

Presence of un pulverised dry lumps reducesthe strength

Compaction

By increasing the amount of compaction dry

density of the mix, strength and durability also

increases


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Curing

Adequate Moisture content is to be retained in

order to accelerate the strength

Additives

There are some additives to improve properties

Lime

Sodium hydroxide Sodium Carbonate

Calcium Chloride


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Design of SoilCement Mix

Soil Cement specimens are prepared with

various cement contents in constant volumes

moulds

The compressive strength of these specimens

tested after 7 days of curing

A graph is plotted Cement content Vs

compressive strength

The Cement Content Corresponding to a

strength of 17.5 kg/cm2 is taken as design

cement content


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Soil Lime Stabilization

Soil- Lime has been widely used as a

modifier or a binder

Soil-Limeis used as modifier in high plasticity

soils

Soil Lime also imparts some binding action

even in granular soils


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Soil-Lime is effectively used in Expansive

soils with high plasticity index.


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Factors affecting Properties of Soil-Lime

Lime Content

Generally increase in lime content causes

slight change in liquid limit and considerable

increase in Plasticity index

The rate of increase is first rapid and then

decreases beyond a certain limit

The point is often termed as lime fixationpoint

This is considered as design lime content


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Type of Lime

After long curing periods all types of limesproduce same effects. However quick limehas been found more effective thanhydrated lime

Calcium Carbonate must be heated at highertemperature to form Quick lime calciumoxide( CaO)

Calcium oxide must be slaked ( by the

addition of water) to form Hydrated lime

Compaction Compaction is done at OMC and maximum

dry density.


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Curing

The strength of soil-lime increases with curingperiod upto several years. The rate of

increase is rapid during initial period

The humidity of the surroundings also affectsthe strength

Additives

Sodium metasilicate, Sodium hydroxide and

Sodium Sulphate are also found useful

additives


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Soil- Bituminous Stabilization

The Basic Principles of this stabilization areWater Proofing and Binding

By Water Proofing inherent strength and

other properties could be retained

Most Commonly used materials are Cutback

and Emulsion

Bitumen Stabilized layer may be used as

Sub-base or base course for all the roads


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Factors affecting properties of soil-bitumen

Soil

The particle size, shape and gradation of the

soil influence the properties of the soil-bitume

mix.

Types of Bitumen

Cutbacks of higher grade should be preferred

Emulsions generally gives slightly inferior

results than Cutback.


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Amount of Mixing

Increasing proportion of bitumen causes adecrease in dry density but increases the

stability after a certain bitumen content

The optimum bitumen content for maximumstability generally ranges from 4 to 6%

Mixing

Improved type of mixing with low mixing period

may be preferred


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Compaction

Effective Compaction results higher

stability and resistance to absorb water

Additives Anti stripping and reactive chemical

additives have been tried to improve the

properties of the mixes Portland cement can also be used along with

the soil bitumen


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Use of Locally Available Materials

in Road Construction


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Necessity

Scarcity of good qualityaggregates / soil for roadconstruction

Production and accumulation ofdifferent waste materials

Disposal and environmentalproblem

Economical and gainful

utilisation


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Limitations of Using Waste Materials

Quality of waste is not controlled bytheir manufacturers

Characteristics of by-products vary in a

wide range Road construction practice is

accustomed to traditional materials ofsteady quality

Specifications of layers compaction oftraditional materials are not suitable forwaste materials


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General Criteria for Use of WasteMaterials

Amount of yearly produced wastematerial should reach a certain lowerlimit

The hauling distance should beacceptable

The material should not have apoissonous effect

The material should be insoluble inwater

The utilisation should not have apollutional effect to the environment


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Special Requirement for Using WasteMaterials

Free from organic matter

Should not swell or decay asinfluenced by water

Should not be soluble in water

Particles should be moderatelyporous


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Industrial wastes

Thermal Power Stations

* Fly ash

* Bottom ash

* Pond ash

Steel Plants

* Blast furnace slag* Granulated blast furnace slag

* Steel slag


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Utilisation of fly ash

Thermal power - Major role in powergeneration

Indian scenario - Use of coal with highash content

- Negligible utilisationof ash produced

Bulk utilisation - Civil engineeringapplications like

construction of roads &embankments


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Can be used for construction of Embankments and backfillsStabilisation of subgrade and sub-baseRigid and semi-rigid pavements

Fly ash properties vary widely, to becharacterised before use

Major constituents - oxides of silica,aluminum, iron, calcium & magnesium

Environmentally safe material for roadconstruction

Possesses many favourable properties forembankment & road construction



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Favourable properties of fly ash Light weight, lesser pressure on sub-soil

High shear strength

Coarser ashes have high CBR value

Pozzolanic nature, additional strength due to self-hardening

Amenable to stabilisation

Ease of compaction

High permeability

Non plastic Faster rate of consolidation and low compressibility

Can be compacted using vibratory or static roller

Engineering properties of fly ash


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Engineering properties of fly ashParameter Range

Specific Gravity 1.90 2.55

Plasticity Non plasticMaximum dry density (gm/cc) 0.9 1.6

Optimum moisture content (%) 38.0 18.0

Cohesion (kN/m2) Negligible

Angle of internal friction (j) 300 400

Coefficient of consolidation Cv (cm2/sec) 1.75 x 10

-52.01 x10-3

Compression index Cc 0.05 0.4

Permeability (cm/sec) 8 x 10-67 x 10-4

Particle size distribution (% of materials)Clay size fraction

Silt size fraction

Sand size fraction

Gravel size fraction

1 10

8 85

7 90

0 10

Coefficient of uniformity 3.1 10.7

Differences between Indian & US fly


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Differences between Indian & US flyashes

Property compared Indian fly ash US fly ash

Loss on ignition(Unburnt carbon)

Less than 2 percent

5 to 8 per cent

SO3 content 0.1 to 0.2 percent

3 to 4 per cent

CaO content 1 to 3 per cent 5 to 8 per cent

Increase inconcentration ofheavy metals

3 to 4 times incomparison tosource coal

10 times or more incomparison to sourcecoal

Rate of leaching Lower Higher


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Fly ash for road embankment

Ideally suited as backfill material for urban/

industrial areas and areas with weak sub soils Higher shear strength leads to greater

stability

Design is similar to earth embankments

Intermediate soil layers for ease ofconstruction and to provide confinement

Side slope erosion needs to be controlled byproviding soil cover

Can be compacted under inclement weatherconditions

15 to 20 per cent savings in construction cost

depending on lead distance


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Fly ash for road embankment

Earth

CoverEarth

Cover

Bottom ash or

Pond ash

Typical cross section of fly ash road embankment


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Approach embankment for secondNizamuddin bridge at Delhi

Length of embankment - 1.8 km

Height varies from 6 to 9 m

Ash utilised - 1,50,000 cubic metre

Embankment opened to traffic in 1998

Instrumentation installed in theembankment showed very goodperformance

Approximate savings due to usage of flyash is about Rs.1.00 Crore


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Approach embankment for secondNizamuddin bridge at Delhi


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Spreading of pond ash

Compaction of pond ash

Second Nizamuddin bridge approach embankment


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Stone pitching for slope

protection

Traffic plying on theembankment

Second Nizamuddin bridge approach embankment



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Utilisation of fly ashFour laning work on NH-6 (Dankuni to Kolaghat)

Water logged area

(soft ground conditions)

Compaction of fly ash over layer of geotextile

Length of stretch

54 kmHeight of embankment 3 to

4 m

Fly ash utilisation 2 Million

cubic metres


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Reinforced fly ash embankment

Fly ash - better backfill material forreinforced embankments

Polymeric reinforcing materials

Geogrids, friction ties, geotextiles

Construction sequence similar toreinforced earth structures


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Okhla flyover approach embankment

First geogrid reinforced fly ash approachembankment constructed in the country

Length of embankment

59 m Height varied from 5.9 to 7.8 m

Ash utilised 2,700 cubic metre

Opened to traffic in 1996 Performance has been very good


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Pond AshFill

7.8 to5.9 m

Facingpanels

Filtermedium Geogrids

Reinforced foundation mattress of bottom ash



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Erection of facing panels

Rolling of pond ash


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Support provided tofacing panels during

construction

Laying of geogrids



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Hanuman Setu flyover approach embankment

Geogrid reinforced fly ash approachembankment

Length of embankment 138.4 m

Height varied from 3.42 m to 1.0 m

Opened to traffic in 1997


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Sarita Vihar flyover approach embankment

Length of embankment 90 m

Maximum height 5.25 m

Embankment opened to traffic inFeb 2001

Polymeric friction ties used forreinforcement


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Sarita Vihar flyover reinforced approach embankment

Arrangement offriction ties before

laying pond ash

Laying of friction ties


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Compaction usingplate vibrator near

the facing panels

Compaction of pondash using static andvibratory rollers

Sarita Vihar flyover reinforced approach embankment

Fl h f d t ti


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Fly ash for road construction Stabilised soil subgrade & sub-

base/base courses Mixing with soil reduces plasticitycharacteristics of subgrade

Addition of small percentage of lime or

cement greatly improves strength Leaching of lime is inhibited and

durability improves due to addition of flyash

Pond ash & bottom ash can also bestabilised

Lime-fly ash mixture is better alternativeto moorum for construction of WBM /

WMM


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Construction of semi-rigid/ rigidpavements

Lime-fly ash concrete

Dry lean cement fly ash concrete

Roller compacted concrete

Fly ash admixed concrete pavements

Lime-fly ash bound macadam

Precast block paving

High performance concrete

Fly ash for road construction


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WBM Gr II/WMM 150 mm

WBM Gr III/WMM 75 mm

GSB 350 mm

BM 75 mm

DBM 100 mm

Bituminous concrete 40 mm

Typical cross section of flexiblepavementconventional section


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Fly ash + 6% cementstabilised layer 150 mm

Typical cross section of flexiblepavementusing fly ash

WBM Gr III/WMM 75 mm

Pond ash 350 mm

BM 75 mm

DBM 100 mm

Bituminous concrete 40 mm


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Pond ash 300 mm

DLFC 100 mm

Fly ash admixed PQC 300 mm

Typical cross section of rigid pavementusing fly ash

D t ti d j t


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Demonstration road projectat Raichur

Total length of the road 1 km

Five sections of 200 m each with different

pavement sections

Pond ash has been used for replacing moorum

in sub-base course

Stabilised pond ash used for replacing part of

WBM layer One rigid pavement section using DLFC and

RCCP technology was laid

Performance of all the specifications is good


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Mixing of lime

stabilised pond ash

Compaction ofstabilised pond ashusing road roller

Demonstration road project using fly ash at Raichur


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Construction of roller

compacted concretepavement

View of thedemonstration roadstretch after three years

Demonstration road project using fly ash at Raichur

Demonstr

ation road project using fly ash


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A rural road near Dadri in District GautamBudh Nagar, Uttar Pradesh was selected

Total length of road 1.4 km

Bottom ash used as embankment fill

Base course constructed using fly ashstabilised with 8% cement

RCCP Wearing course 10 cm thickness

RCCP Mix proportion 1:2:4 30 per cent of cement and 20 per cent of

sand replaced with fly ash in RCCP

Shoulders 8% cement stabilised fly ash

Demonstration road project using fly ashnear Dadri (U.P)


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Bottom ash

RCCP wearing course - 0.1 m

Stabilised fly ash

base - 0.1 mStabilised fly ash

Shoulder

Soil cover

Demonstration road project using fly ashnear Dadri (U.P) Typical section


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Stabilised base course

Compaction of RCCPMixing & laying of RCCP

Demonstration

road project usingfly ash near Dadri

(U.P)

IRC Guidelines / Specifications


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IRC Guidelines / Specifications

Guidelines available on pavement construction

IRC 60 Tentative guidelines for use of lime flyash concrete as pavement base or sub-base

IRC 68 Tentative guidelines on cement fly

ash concrete for rigid pavement construction

IRC 74 Tentative guidelines for lean cementconcrete and lean cement fly ash concrete asa pavement base or sub-base

IRC 88 Recommended practice for lime flyash stabilised soil as base or sub-base inpavement construction

Guidelines for use of fly ash in road


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Guidelines for use of fly ash in roadembankments

Published recently by Indian Roads Congress(SP- 58:2001)

Includes design aspects also

Handling and construction

Loose layer thickness of 400 mm can beadopted if vibratory rollers are used

Moisture content - OMC + 2 per cent

Use of vibratory rollers advocated

Minimum dry density to be achieved - 95per cent of modified Proctor density

Ash layer and side soil cover to beconstructed simultaneously

l f l l


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Utilisation of steel slags

Total production of slag from steelindustries is about 8.0 million tonnes

Types of slags

Blast furnace slag Granulated blast furnace slag

(GBFS)

Air cooled slag Steel slag

Granulated blast


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Granulated blastfurnace slag

Contains reactive silicaSuitable for lime / cementstabilisation

Air cooled blast

furnace slagNon reactive

Suitable for use as

coarse aggregates

CRRI work on utilisation of


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CRRI work on utilisation ofsteel slags

Characterisation of slags produced atdifferent steel plants

Laboratory studies on Lime-GBFS mixes

Semi-field studies on Lime-GBFS concrete

Test track studies on usage of slags inroad works

Properties of air cooled slag


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p gProperty Durgapur Bhilai Rourkela Delhi

QuartziteSpecificationrequirements

Specific

gravity

2.78

2.82

2.82

3.33

2.97

2.99

2.67 -

Waterabsorption(%)

1.53 1.72

0.58 1.38

0.74 1.29

0.48 2% Max

Los

Angelesabrasionvalue (%)

18.80 25.00 14.28 34.00 40% Max

Impactvalue (%)

15.79 14.80 16.90 24.50 30% Max

Soundnessvalue (%) 1.66 1.17 0.33 0.17 12% Max

Percentagevoids

46.40 43.90 43.10 43.80 -


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Steel slags

Obtained as a waste product duringproduction of steel

Particle size varies from 80 mm to 300microns

Compared to blast furnace slag, steelslag contains lower amount of silica,higher amounts of iron oxide and

calcium oxide Due to presence of free lime, steel slag

should be weathered before using it inconstruction

Road projects executed under CRRI


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Road projects executed under CRRIguidance using slags

Plant roads at Visakhapatnam

Test tracks in collaboration with APPWD using slags from Visakhapatnam

Steel Plant

Test tracks in collaboration with OrissaPWD using slags from Rourkella Plant

Test tracks at R&D Centre for Iron &Steel, Ranchi using Slags from BokaroPlant


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Construction oftest track using

slag at Orissa

Labour based techniquesfor construction of

stabilised layer

Lime


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View of finishedsurface of road

constructedusing slags at

Orissa

Limestabilisationof iron slags

(Orissa)

Processed municipal wastes


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p

Processed municipal wastesutilised for construction oftest track on village roadnear Delhi

Stabilised municipal wasteused for construction of sub-base layer

Performance of stretch isgood

Kimberlite tailings


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Kimberlite tailings

Kimberlite tailings are waste produced from

diamond mining Can be used in base or sub-base course by

adopting mechanical or cement stabilisation

High value of water absorption makes them

1.4 soil stabilization technique mekanis dan kimiawi

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