soil stabilisation and methods

7/24/2019 soil stabilisation and methods

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Soil Stabilization

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The soil stabilization means the improvement of stability

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 choose

effective and economical method of soil stabilization

• Designing the Stabilized soil mix for intended stability and

durability valueswww.ustudy.in



Reducing the volume of voids =

reducing the porosity.

Filling the voids that cannot be

eliminated = reducing the

permeability.

ncreasing the bonding between

grains = increasing the mechanical

strength.

OBJ!T"#$



%eed for $oil $tabilization

!imited Financial Resources to Provide a

complete networ" Road System to build in

conventional method

#$ective utilization of locally available

soils and other suitable stabilizing agents.

#ncouraging the use of ndustrial%astages in building low cost construction

of roads.

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&ethods of SoilStabilization

'&echanical Stabilization

'Soil (ement Stabilization

'Soil !ime Stabilization

'Soil Bitumen Stabilization

'!ime Fly ash Stabilization

'!ime Fly ash Bound &acadam.

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&echanical stabilization is accomplished by

mi)ing or blending soils of two or more

gradations to obtain a material meeting the

re*uired speci+cation. ,he soil blending may

ta"e place at the construction site- a central

plant- or a borrow area. ,he blended material is

then spread and compacted to re*uired densities

by conventional means.

&echanical Stabilization



Factors Affecting Mechanical

Stabilization

• &echanical Strength of aggregates

• radation• Properties of the Soil

• &ineral (omposition

• (ompaction

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&echanical Strength

' %hen the soil is used in small proportion to

+ll up the voids the crushing strength ofaggregates is important

radation

' / well graded aggregate soil mi) results in ami) with high dry density and stability values

Properties of soil

' / mi) with Plasticity nde)- results poorstability under soa"ing conditions. 0ence it isdesirable to limit the plasticity inde) of the soil

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PHYSICAL

STABILISATION

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23,# 4F,#1 S4&# /55,6#S &/7 /!S4 B# /55#5 F4R ,0#P3RP4S#.

.CEMENT STABILISATION

2. LIME STABILISATION

3. BITUMEN STABILISATION

4. CHEMICAL STABILISATION

5. RESIN STABILISATION



Soil (ement Stabilization

' Soil (ement is an intimate mi) of soil-cement and water- compacted to form astrong base course

' (ement treated or cement modi+ed soilrefers to the compacted mi) when cementis used in small proportions to impart some

strength' Soil (ement can be used as a sub9base or

base course for all types of Pavements



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Factors a$ecting soil cementstabilization

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' Soil

' Cement

' Pulverization and Mixing

' Compaction

' Curing

' Additives



Soil

THE PHYSICAL P!PETIES

' Particle Size 5istribution

' (lay content

' Speci+c Surface

' !i*uid limit and Plasticity nde)

(ement

A increase in cement content

generall" causes increase in strengt# and durabilit" www.ustudy.in



Pulverisation and &i)ing' Better the Pulverisation and degree of

mi)ing- higher is the strength

' Presence of un pulverised dry lumps reducesthe strength

(ompaction

' By increasing the amount of compaction drydensity of the mi)- strength and durabilityalso increases

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( i



(uring

/de*uate &oisture content is to be retainedin

order to accelerate the strength

/dditives

,here are some additives to improveproperties

' !ime

' Sodium hydro)ide

' Sodium (arbonate

' (alcium (hloridewww.ustudy.in



Soil !ime Stabilization

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' Soil9 !ime has been widely used as a

modi+er or a binder

' Soil9!ime is used as modi+er in highplasticity

soils' Soil !ime also imparts some bindingaction

even in granular soils



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When lime reacts with soil there isexchange of

cations in the absorbed water layer

and a decreasein the plasticity of the soil occurs.

The resulting material is more friablethan the

original clay, and is, therefore moresuitable as sub-

F t $ ti P ti f S il



Factors a$ecting Properties of Soil9

!ime

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!ime (ontent

' enerally increase in lime content causesslight change in li*uid limit andconsiderable increase in Plasticity inde)

' ,he rate of increase is +rst rapid and then

decreases beyond a certain limit

' ,he point is often termed as lime +)ationpoint

,his is considered as design lime content



,ype of !ime

/fter long curing periods all types of limes

produce same e$ects. 0owever *uic" limehas been found more e$ective than hydratedlime

(alcium (arbonate must be heated at higher

temperature to form 2uic" lime calciumo)ide: (a4; (alcium o)ide must be sla"ed : by the

addition of water; to form 0ydrated lime

(ompaction (ompaction is done at 4&( and ma)imum

dry density.

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(uring

' ,he strength of soil9lime increases withcuring

period upto several years. ,he rate ofincrease is rapid during initial period

' ,he humidity of the surroundings alsoa$ects the strength

/dditives' Sodium metasilicate- Sodium hydro)ide and

Sodium Sulphate are also found useful

additives www.ustudy.in



Soil9 BituminousStabilization

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' ,he Basic Principles of this stabilization are%ater Proo+ng and Binding

' By %ater Proo+ng inherent strength and

other properties could be retained

' &ost (ommonly used materials are(utbac" and #mulsion

' Bitumen Stabilized layer may be used as

Sub9base or base course for all the roads



Factors a$ecting properties of soil9bitumen

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Soil

' ,he particle size- shape and gradation of thsoil in<uence the properties of the soil9bitumen mi).

,ypes of Bitumen

' (utbac"s of higher grade should be preferre

' #mulsions generally gives slightly inferiorresults than (utbac".



/mount of &i)ing

' ncreasing proportion of bitumen causes adecrease in dry density but increases thestability after a certain bitumen content

' ,he optimum bitumen content for ma)imumstability generally ranges from to >?

&i)ing

' mproved type of mi)ing with low mi)ingperiod

may be preferred

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(ompaction

' #$ective (ompaction results higher

stability and resistance to absorbwater

/dditives

' /nti stripping and reactive chemical

additives have been tried toimprove the properties of the mi)es

' Portland cement can also be used

along with the soil bitumenwww.ustudy.in



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T#eEnd

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soil stabilisation and methods