Stabilization of soil using bitumenous emulsions

Stabilization of soil using

BITUMENOUS EMULSIONS

Presented by:

k.Prashanth kumar

Introduction:

For any land-based structure, the foundation is very important

and has to be strong to support the entire structure. in order for the

foundation to be strong, the soil around it plays a very critical role.

so, to work with soils, we need to have proper knowledge about their

properties and factors which affect their behavior. the process of soil

stabilization helps to achieve the required properties in a soil needed

for the construction work.

From the beginning of construction work, the necessity of

enhancing soil properties has come to the light. Ancient civilizations

of the Chinese, Romans and Incas utilized various methods to

improve soil strength etc., some of these methods were so effective

that their buildings and roads still exist.

Here, in this project, soil stabilization has been done with the help

of randomly distributed polypropylene fibers obtained from waste

materials. the improvement in the shear strength parameters has

been stressed upon and comparative studies have been carried out

using different methods of shear resistance measurement.

Definitions and Terminology:

SOIL

CLAY

LIME

CEMENT

ATTERBERG LIMITS

LL (LIQUID LIMIT)

PL (PLASTIC LIMIT)

SL (SHRINKAGE LIMIT)

DENSITY

PI (PLASTICITY INDEX OR IP)

STABILIZING ADDITIVE

Soil – soil is sediment or other unconsolidated accumulation of solid particles produced by the physical and/or chemical disintegration of rock, soil may or may not contain organic material (ASTMD2487).

Clay – Clay is type of cohesive soil composed of very fine material particles; clay is one of the fine-grained soils defined by the Unified Soil Classification System.

Lime – Lime is a white or grayish-white, odorless, lumpy, very slightly water soluble solid, CaO, that when combined with water forms Calcium Hydroxide (Slaked Lime). Calcium Hydroxide is chiefly used in mortars, plasters, and cements.

Cement – Portland cement is hydraulic cement made by heating limestone and clay mixture in a kiln and pulverizing the resulting material.

Atterberg Limits – The Atterberg Limits are a basic measure of the natureof a fine – grained soil. Depending on the water content of the soil, itmay appear in four states: solid, semi-solid, plastic and liquid. In eachstate the consistency and behavior of a soil is different and thus so, areits engineering properties. Thus, the boundary between each state canbe defined based on soil behavior. These limits were put forward byAlbert Atterberg, a Swedish chemist, in the late 1800’s, and laterredefined by Arthur Casagrande.

ll (liquid limit) – The liquid limit of a fine-grained soil is a boundary between the liquid and plastic state of that particular soil, expressed as a moisture content percentage (by weight).

Pl (plastic limit) – The plastic limit of a fine-grained soil is the boundary between the plastic and semi-solid states for that particular soil, expressed as a moisture content percentage (by weight).

SL (Shrinkage Limit) – The shrinkage limit of a fine grained soil is

defined as the moisture content at which no further volume

change occurs with further reduction in moisture content (SL

represents the amount of water required to fully saturated the soil

(100% of Saturation))

density – density is the measure of the relative weight of any material compared to its occupied volume, expressed in kilograms per cubic meter (pounds per cubic foot). the increase in density is limited only by the degree of solidity that can be achieved in a material by total elimination of voids between the particles in the mass.

PI (plasticity index or ip) – PI is the numerical difference of liquid limit and plastic limit of a fine grained soil.

Ip= wl - w p

Stabilizing additive – A stabilizing additive is a mechanical, chemical or bituminous additive (or other material) used to maintain or increase the strength and durability, decrease the moisture sensitivity, or otherwise improve the engineering properties of a soil or other materials used for construction.

SOIL STABLIZATION:

PRINCIPLES OF SOIL STABILIZATION

Evaluating the soil properties of the area under

consideration.

Deciding the property of soil which needs to be altered

to get the design value and choose the effective and

economical method for stabilization.

Designing the Stabilized soil mix sample and testing it in

the lab for intended stability and durability values.

Advantages: It Improves The Strength Of The Soil, Thus, Increasing The Soil Bearing Capacity.

It Is More Economical Both In Terms Of Cost And Energy To Increase The Bearing

Capacity Of the Soil Rather Than Going For Deep Foundation Or Raft Foundation.

It Is Also Used To Provide More Stability To The Soil In Slopes Or Other Such Places.

Sometimes Soil Stabilization Is Also Used To Prevent Soil Erosion Or Formation Of Dust,

Which is Very Useful Especially In Dry And Arid Weather.

Stabilization Is Also Done For Soil Water-proofing; This Prevents Water From Entering Into

The soil And Hence Helps The Soil From Losing Its Strength.

It Helps In Reducing The Soil Volume Change Due To Change In Temperature Or

Moisture content.

Stabilization Improves The Workability And The Durability Of The Soil.

Methods of stabilization:

I. Mechanical Method Of Stabilization.

II. Additive method of stabilization:

a. Cementation Stabilization.

b. Bituminous Stabilization.

c. Argillation Stabilization.

d. Silicification Stabilization.

e. Electrochemical Stabilization.

f. Thermal Stabilization.

g. Fiber Reinforcements.

Oriented Fiber Reinforcement.

Random Fiber Reinforcement.

Uses of stabilization:

Quality Improvement: The most common improvements achievedthrough stabilization include better soil gradation, reduction of plasticityindex or swelling potential, and increases in durability and strength. inwet weather, stabilization may also be used to provide a workingplatform for construction operations. these types of soil qualityimprovement are referred to as soil modification

Thickness reduction: The strength and stiffness of a soil layer canbe improved through the use of additives to permit a reduction indesign thickness of the stabilized materials compared with anunsterilized or unbound material. Procedures for designingpavements that includes stabilized soils are presented in TM 5-822-5/AFM 88-7, Chap. 3, TM 5-825-2/AFM 88-6, Chap. 2, TM 5-825-3/AFM 88-6, Chap. 3. The design thickness of abase or sub-basecourse can be reduced if the stabilized materials meet thespecified gradation, strength, stability and durability requirementsindicated in this Technical Manual for the particular type ofmaterial.

Soil Stabilization Process

Stabilization with

BITUMENOUS EMULSIONS

What are emulsions?

An emulsion is a dispersion Of small droplets of one liquid in another liquid.

Emulsions can be formed by any two immiscible liquids, but in most emulsions one of the phases is water.

Oil-in-water (O/W) emulsions are those in which the continuous phase is water and the disperse (Droplet) phase is an “oily” liquid. Water-in-oil (W/O) “inverted” emulsions are those in which the continuous phase is an oil and the disperse phase is water.

Types of emulsions:

A. O/W emulsion,

B. W/O emulsion,

C. multiple W/O/W

Bitumen Emulsion Is A 2-phase System Consisting Of

Bitumen

Water

Other Additives

• The bitumen is dispersed throughout the water phase in form of

discrete globules, held in suspension by electrostatic charges

stabilized by emulsifier

• The Emulsion contains 40-75% of bitumen,.1-2.5%emulsifier,25-

60%water and other ingredients

• Typically of .1 – 50 µm in diameter.

• It is mainly dark brown in color after breaking changes to black.

WHY BITUMEN EMULSIONS ?

Primary Objective Is To Use For Road Surfacing Without Much

Heating.

As main advantages this improves the handling of bitumen at

room temperature.

Promotes surface interactions .

Its mixture with the aggregate attains full strength.

Economical and saves energy .

Reduced atmosphere pollution.

Water can also added before use to dilute as per requirement.

Rains can not effect it at the time of use and after use.

Stabilization of chalky soil

Chalky Soil:

Sometimes called basic soils, they are

always very alkaline. Chalk is a solid, soft

rock which breaks down easily. It is very

free draining, and chalky soils hold little

water and dry out easily. Chalky soils are

fertile, but many of the nutrients are not

available to plants because of the high

alkalinity of the soil, which prevents the

absorption of iron by plant roots.

Experiments on Proctor compaction

test

Scope

Apparatus

Preparation of Sample

Procedure to Determine the relationship

between the dry density of the soil and

the moisture content of the soil.

Proctor compaction test

1.878

1.923

1.95

1.971

2.019

1.942

1.86

1.88

1.9

1.92

1.94

1.96

1.98

2

2.02

2.04

0 2 4 6 8 10 12 14 16 18

Dry

de

nsi

ty in

g/c

c

Moisture content %

Relation between dry density and moisture content% of soil

Computing from graph

Optimum Moisture Content (OMC) = 13.9%

Maximum Dry Density (MDD) = 2.019 g/cc

Proctor Compaction Test Using 6% Bitumenous Emulsions

2.019

2.043

2.113

2

1.98

2

2.02

2.04

2.06

2.08

2.1

2.12

0 2 4 6 8 10 12 14

Dry

de

nsi

ty in

g/c

c

Moisture content %

Relation between Dry density and moisture content% of soil using 6% of

Bitumenous Emulsions





1.968

1.971

1.985

1.966

1.965

1.97

1.975

1.98

1.985

1.99

0 2 4 6 8 10 12 14

Dry

de

nsi

ty in

g/c

c

Moisture content %







1.896

2

2.034

1.834

1.8

1.85

1.9

1.95

2

2.05

2.1

0 2 4 6 8 10 12 14

Dry

de

nsi

ty in

g/c

Moisture content %






Experiments on California bearing ratio

test

Scope

Apparatus

Preparation of Sample

Procedure to Determine the California

bearing test ratio by conducting a

load penetration test

California bearing ratio test

6 8 9 10 1115

2026

46

64

84

0

10

20

30

40

50

60

70

80

90

0 2 4 6 8 10 12 14

Pro

vin

g rin

g re

ad

ing

Penetration reading

relation between penetration reading and proving ring reading of soil

California bearing ratio test using 7% Bitumenous Emulsions

20 3246

6278 90

126142

210

282

334

0

50

100

150

200

250

300

350

400

0 2 4 6 8 10 12 14

relation between penetration reading and proving ring reading of soil

using Bitumenous Emulsions

Conclusion

1. Base On Proctor Compaction Test On Soil Sample

Maximum Dry Density Is 2.019 g/cc

Optimum Moisture Content Is 13.9%

By Addition Of 6% BITUMENOUS EMULSION To The Soil Sample

Increase In Maximum Dry Density And Decrease In Optimum Moisture Content









2. Base On California Bearing Ratio Test On Soil Sample

CBR value at 2.5mm, 5mm, 7.5mm, 10mm and 12.5mm

We found 2.376%, 3.74%, 5.177%, 5.957% and 6.906%.

By the addition of 7% Bitumenous Emulsion To The Soil Sample

CBR value at 2.5mm, 5mm, 7.5mm, 10mm and 12.5mm

We found 16.85%, 20.45%, 23.63, 26.24% and 27.46%.

By the addition of Bituminous Emulsion increase in CBR value.

3. Overall it can be concluded that Bituminous Emulsion soil can be considered to

be good ground improvement technique specially in engineering projects on

weak soils where it can act as a substitute to deep/raft foundations, reducing

the cost as well as energy.

Soil Types

When looking to buy land it is always important to consider the soil type in relation to the use of the land. Each soil type has different properties -divided into six categories.

Chalky Soil:

Sometimes called basic soils, they are always very alkaline. Chalk is a solid, soft rock which breaks down easily. It is very free draining, and chalky soils hold little water and dry out easily. Chalky soils are fertile, but many of the nutrients are not available to plants because of the high alkalinity of the soil, which prevents the absorption of iron by plant roots.

Clay Soil:

The clay forms a heavy mass which makes it difficult for air, water and plant roots to move through the soil when wet. Once dry they form rock-hard clots. Blue or grey clays have poor aeration and must be loosened in order to support healthy growth. Red colour in clay soil indicates good aeration and a "loose" soil that drains well. Plants can take advantage of the high level of nutrients if drainage is adequate.

Loam Soil:

Considered to be the perfect soil, a mix of 40 % sand, 40% silt and 20% clay. Due to mix variations loam can range from easily workable fertile soils full of organic matter, to densely packed sod. Characteristically they drain well, yet retain moisture and are nutrient rich, making them ideal for cultivation.

Peat Soil:

Provided they are not too acid and have effective sub drainage, these are rich in plant

foods. Converting existing soil into a peat type soil is achieved by adding large amounts

of organic matter. You must avoid making your soil too acid though, and careful choice

of organic matter is needed.

Sandy Soils:

Sandy soils generally have a fine grained texture. They retain very little in the way of

water, fertilizers or nutrients which means they are extremely poor. Prone to over-

draining and summer dehydration, and in wet weather can have problems retaining

moisture and nutrients and can only be revitalized by the addition of organic matter.

Sandy soils are light and easy to dig, hoe and weed.

Silty Soil:

Silty soil is considered to be among the most fertile of soils. Silt is often found in river

estauries, because the fine particles are washed downstream and deposited when the

water flows more slowly. It is also soft and smooth, with individual pieces close together.

It too holds a lot of water, but the slightly larger particles make it a little better at

draining than clay.

Stabilization of soil using bitumenous emulsions

Engineering

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