Sulphate Resistance

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SULPHATE RESISTANCE OF TERNARY

BLENDED

FIBRE REINFORCED CONCRETEA DISSERTATION ON

PARTIAL FULFILLMENT OF MASTER OF TECHNOLOGY

BY

A.BHASKARRoll No.11016T6013,M.Tech IV Semester

Under The Guidence Of

Shri D.Hari Krishna Asso.Prof.CED, KITS, Warangal

DEPARTMENT OF CIVIL ENGINEERING

KAKATIYA INSTITUTE OF TECHNOLOGY AND SCIENCE, WARANGAL - 15.


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CONTENTS

OBJECTIVES

INTRODUCTION

FACTORS DEPENDS ON SEVERITY OF SULPHATE ATTACK

SCOPE

REFERENCES


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OBJECTIVES

To study the effect of sodium sulphate at 5% concentration on Ternary

blended fibre reinforced concrete at 90 days of immersion in sulphate

solution.

To find the optimum mix to resist the effect of Sulphates.

To study the effect of partial replacement of cement by silica and Fly ash in

different percentages at 28 days compressive strength.


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INTRODUCTION

Why Ternary blend

The particle packing is the main reason. The fly ash particle is often finer

than the cement. The silica fume particles can perform better in particle

packing since these are intermediate size.


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Effect of ternary cement system

Micro silica compensates for low early strength of concrete.

Fly ash increases long-term strength development of micro silica concre

Fly ash due to presence of spherical leads to improved workability and

reduction in water demand


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Source of Sulphate

Seawater and ground water are the main sources of external sulphate

Industrial effluents and wastes such as in industries associated

with the manufacture of chemicals, batteries, aluminium and in

the mining industry.

Internal Source

Portland cement might be over-sulfated.

presence of natural gypsum in the aggregate.

Admixtures also can contain small amounts of sulfates

External Source


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Mechanism of Sulphate Attack

Reaction of the sulfate with calcium hydroxide liberated during thehydration of the cement, forming calcium sulfate (gypsum)

Reaction of the calcium sulfate with the hydrated calcium aluminate,

forming calcium sulpho aluminate (ettringite).

Both of these reactions result in an increase in the volume of solids

which is the cause of expansion and disruption of concretes exposed

to sulfate solutions.


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Recommendations for normal concrete subject to

sulfate attack

Exposure

Water soluble

sulfate (SO4) in

soil, percent

Sulfate (SO4) in

water, ppm

Recommendati

ons

NEGLIGIBLE Under 0.1 Under150

MODERATE0.1 to 0.2 150 - 1500

PS cement

0.5 W/C Ratio

SEVERE 0.2 to 2.0 1500 10,000

PS cement

0.45 W/C Ratio

VERY SEVERE Over 2.0 Over 10,000

PS cement+Admix

>0.45 W/C

Ratio


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Severity of sulfate attack on concrete depends on

the following

Type of sulfate

Concentration of the sulfate

Whether the sulfate solution is stagnant or flowing

Pressure

Temperature


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Prevention measures of Sulphate attack

1. Cement type and content:

2. Admixtures : That effects reduction in water-cement ratio

and/or increased workability can enhance the sulfate resistance

of concrete, provided they are not used to reduce its cement

content

Cements with low C3A content are less vulnerable to sulfate

attack

Higher cement content significantly reduces the rate of sulfate

attack


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SCOPE OF PRESENT INVESTIGATION

The present experiment is carried out to investigate the strength of

ternary blended steel fiber reinforced concrete on M30 grade

concrete with 6% and 15% replacement of cement by silica fume

and fly ash respectively and 0%, 0.5%, 0.75%, 1.0% and 1.25%

addition of steel fibers


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Mehta, P K Concrete Structures, Properties and Materials Prentice Hall,

Inc, Englewood Cliffs, New Jersey,

M S Shetty,Concrete Technology, Published May 1st 1987 by Chand (S.) &

Co Ltd, 632 pages, Hardcover.

M L Gambhir, Concrete Technology, Published by Tata McGraw-Hill

Education, 01-Jul-2004

Adam M Neville, Properties ofConcreteBookby John Wiley & Sons

Publisher

References

CEMENT CONCRETE & AGGREGATES Australia JULY 2OO2 journal


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THANKYOU

Sulphate Resistance

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