DEPLETION OF NATURAL ROCK & PROCESSING OF AGGREGATES

PRESENTED BY : FRASAT MEHAMOOD ABBASI

AGGREGATES ARE INERT MATERIALS WHICH ARE MIXED WITH BINDING MATERIALS SUCH AS CEMENT OR LIME FOR MANUFACTURING OF MORTAR OR

CONCRETE.

AGGREGATES ARE THE IMPORTANT CONSTITUENT IN CONCRETE. AGGREGATES ARE GRANULAR MATERIAL DERIVED FROM THE MOST PART OF THE NATURAL ROCK, CRUSHED STONES, NATURAL GRAVELS OR SAND

AGGREGATES ARE GENERALLY OCCUPY ABOUT 70-80 % OF VOLUME OF A CONCRETE AND THEREFORE BE EXPECTED TO HAVE AN IMPORTANT INFULENCE ON IT’S PROPERTIES

Crushed Stone: Quarried from a ledge rock

Gravel: ◦ Mined or dredged

from natural deposits

Mining or Blasting

Crushing

◦ Primary

◦ Secondary

Sizing

◦ Gradation

◦ Fines

Testing (QC/QA)

Recycled Concrete: ◦ Quarried from

pavements or other sources

Slag or Foundry Sand: ◦ Mined from industrial

stockpiles

GOOD QUALITIES OF AN IDEAL AGGREGATE:

An ideal aggregate used for the manufacturing ofconcrete and mortar, should meet the followingrequirements.

(1) It should consist of natural stones, gravels andsand or in various combinations of these materials.

(2) It should be hard, strong and durable.

(3) It should be dense, clear and free from anycoating.

(4) It should be free from injurious vegetablematters.

(5) It should not contain flaky (angular) andelongated pieces.

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PHYSICAL PROPERTIES

PARTICLE SIZE DISTRIBUTION

SPECIFIC GRAVITY & WATER ABSORPTION

CLAY AND FRIABLE PARTICLES

FLAKINESS & ELONATION

LOS ANGELES ABRASSION

AGGREGATE CRUSHING VALUE

AGGREGATE IMPACT VALUE

TEN PERCENT FINES VALUE

SOUNDNESS

TEST NAME APPLICABLE STANDARD

SPECIFICATION LIMIT

Water absorption ASTM C 127/128 Max 2 %

Flakiness BS 812 Part 105.1 Max 25%

Elongation Bs 812 Part 105.2 Max 25%

Clay lump ASTM C142 Max 1%

Acid Soluble Sulphate BS 812 Part 116 Max 0.3%

Acid Soluble Chloride Bs 812 Part 117 Max 0.03%

Sand Equivalent ASTM D2419 Min 75%

Soundness ASTM C88 Max 12%

Impact Value BS 812 Part 112 Max 30%

10% fine Value Bs 812 Part 111 Min 100KN

CLASSIFICATION BASED ON SOURCE:>Natural aggregates:

This kind of aggregate is taken from natural deposits without changing their nature during the process production such as crushing and grinding.

>Manufactured (synthetics) aggregates:

This is a kind of man-made materials produced as a main product or an industrial by-product. Some example are blast furnace slag, air cooled slag and broken bricks. Synthetics aggregates are produced by thermally processed materials such as expanded clay and shale used for making light weight concrete.

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a)CLASSIFICATION BASED ON SIZE:

>Coarse aggregate:

Aggregate which retained on the No.4 (4.75mm) sieve. The function of the coarse aggregate is to act as the main load-bearing component of the concrete.

>Fine aggregate:

Aggregate passing No.4(4.75mm) sieve and predominantly retained on the No.200 (75µ) sieve. The fine aggregate serve the purpose of filling all the open space in between the coarse particles.

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CLASSIFICATION BASED ON UNIT WEIGHT:

Aggregates are classified as Light-weight,

Heavy-weight and Normal-weight aggregate depending on weight and specific gravity.

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AGGREGATE SPECIFIC GRAVITYMg/m3

UNIT WEIGHT

BULK DENSITY(Mg/m3

EXAMPLE

Normal-weight

2.5-2.7 23-26 15.20-16.80

sand

Heavy-weight

2.8-2.9 25-29 >20.80 Scrap iron

Light-weight

12 <11.20 dolomite

CLASSIFICATION BASED ON SHAPE:

The shape of aggregates is an important characteristic, since it affect the workability of concrete.

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CLASSIFICATION EXAMPLE

Rounded River or seashore gravels

Partially Rounded Pit sands & Gravels

Angular Crushed Rocks

Flaky Laminated rocks

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ELONGATED

Flaky ANGULAR

Rounded

CLASSIFICATION BASED ON SUFACE TEXTURE:

Surface texture is a measure of the smoothness and

roughness of aggregate. The grouping of aggregate is broad andis based on visual examination of the specimen. As per IS:383-1970 the aggregates are classified into five groups, namely,Glassy, Smooth, Granular, Crystalline, Honeycombed and Porous.

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CLASSIFICATION EXAMPLES

Glassy Black flint

Smooth Gravel, Marble

Granular Sandstone

Rough Basalt

Crystalline Granite

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SMOOTH ROUGH

THIS TEST COVERS THE DETERMINATION OF PARTICLE SIZE

DISTRIBUTION OF COARSE AND FINE AGGREGATES. A SAMPLE OF

DRY AGGREGATES OF KNOWN MASS IS SEPARATE THROUGH A

SERIES OF SIEVES OF PROGRESSIVELY SMALLER OPENING FOR

DETERMINATION OF PARTICLE SIZE DISTRIBUTION.

SPECIFIC GRAVITY AND WATER ABSORPTION OF COARSE & FINE AGGREGATES

ASTM C 127&128 & BS 812 PART 2 :1995

DETERMINE THE BULK AND APPARENT SPECIFIC GRAVITIES AND WATER ABSORPTION OF COARSE AND FINE AGGREGATES. ABSORPTION IS THE PROCESS BY WHICH WATER IS DRAWN INTO AND TRENDS TO FILL THE PERMEABLE PORES IN A POROUS SOLID BODY.

FLAKINESS INDEX

THE FLAKINESS INDEX OF AN AGGREGATE SAMPLE IS FOUNDBY SEPERATING THE FLAKY PARTICLES AND EXPRESSING THEIR MASS AS A PERCENTAGE OF THE MASS OF SAMPLETESTED

ELONGATION INDEX

THE ELONGATION INDEX IS FOUND BY SEPERATING THEELONGATED PARTICLE AND EXPRESSING THEIR MASS AS A PERCENTAGE OF THE MASS OF SAMPLE TESTED

THIS METHODCOVERS A PROCEDURE FOR

TESTING SIZES OF COARSE AGGREGATE SMALLER THAN

37.5 MM FOR RESISTANCE TO DEGRADATION USING THE

LOS ANGELES MACHINE.

AGGREGATE CRUSHING VALUE & AGGREGATE IMPACT VALUE

BS 812 PART 110:1990 & BS 812 PART 112:1990

ACV-THIS METHOD GIVES A RELATIVE MEASURE OF THE RESISTANCE OF AN AGGREGATE TO CRUSHING UNDER A GRADUALLY APPLIED COMPRESSIVE LOAD

AIV-THIS METHOD GIVES A RELATIVE MEASURE OF THE RESISTANCE OF AN AGGREGATE TO SUDDEN SHOCK OR IMPACT

We collect sample from different source and different size to find out quality of aggregate. We conduct different test as per international standard.

Following test was carried out.

PARTICLE SIZE DISTRIBUTION

AGGREGATE LOSS ANGELES ABRASION

AGGREGATE ELONGATION INDEX

AGGREGATE FLAKINESS INDEX

AGGREGATE CHLORIDE CONTENT

AGGREGATE SULPHATE CONTENT

Sieve size National Quarry DOHA QUARRY RAJ STONE

28mm 100% 100% 100%

20mm 97% 96% 95.6%

14mm 30% 31% 37.9%

10mm 2.0% 1.2% 3.4%

6.3mm 0% 1% 0.7%

5.0 0% 0% 0.6%

0.60.7

3.4

37.9

95.6 100

0

10

20

30

40

50

60

70

80

90

100

5mm 6.3mm 10mm 14mm 20mm 28mm

Sieve Sizes

Pa

ss

ing

%

SOURCE NAME NATIONAL QUARRY DOHA QUARRY RAJ STONE

LOSS AGGELES ABRASION 12% 13.9% 10%

ELONGATION INDEX 23% 29% 14%

FLAKINESS ` INDEX 10% 26% 8%

CHLORIDE CONTENT 0.01 0.006 0.01

SULPHATE CONTENT 0.05 0.007 0.04

IN GEOLOGY, ROCK IS A NATURALLY OCCURRING SOLID AGGREGATES OF ONE OR MORE MINERALS.

THE SOLID MINERAL MATERIAL FORMING PART OF THE SURFACE OF THE EARTH AND OTHER SIMILAR PLANETS, EXPOSED ON THE SURFACE OR UNDERLAYING THE SOIL.

THREE GENERAL CLASSES OF ROCK:

SEDIMENTARY ROCK

METAMORPHIC ROCK

IGNEOUS ROCK

Sedimentary rock are formed from particles of sand ,shells, pebbles, and other fragments of material. Together, all these particles are called sediment.

Generally ,sedimentary rock is fairly soft and may break apart or crumble easily.

Metamorphic rocks are formed by subjecting any rock type sedimentary rock, igneous rock or another older metamorphic rock.

Metamorphic rock are formed under the surface of the earth from the metamorphosis that occurs due to intense heat and pressure.

Igneous rocks are formed from the solidification of magma rock material. Rocks formed by the cooling and solidifying of magma materials

Based on Measurement Definition for field use UCSMeasurements

(Mpa)

Extremely weak Gravel sized lumps crush between finger and thumb

0.6-1.0

Very Weak Can be break by pocket knife 1-5

Weak Can be break by pocket knife with difficulty

5-25

Medium strong Can be fractured with a single firm blow of geological hammer

25-50

Strong Fracture on more then one blow of geological hammer

50-100

Very strong Require many blow of geologicalhammer for fracture

100-250

Extremely strong Can be chipped with geological hammer

>250

These test methods cover the determination of the strength of intact rock core specimens in uniaxial and triaxial compression. The tests provide data in determining the strength of rock, namely: the uniaxial strength, shear strengths at different pressures and different elevated temperatures, angle of internal friction, (angle of shearing resistance), and cohesion intercept.