Shape test (Lab)

Pavement

Material Lab

Shape TestPriyansh SinghDepartment of Civil EngineeringIndian Institute of Technology Delhi@ [email protected] web.iitd.ac.in/~cez138070

Pavement Engg. Lab4th February 2015

Pavement Material Lab

Flakiness and Elongation Test4th February 2015

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Introduction



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Introduction



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Flat Particles

Particles whose least dimension is less than 0.6 times its meandimension.

Flakiness IndexIts percentage of that mass of aggregate whose leastdimension is less than 0.6 times its mean dimension.Applicable to particles greater the 6.3mm size



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Thickness Guage

_--

i 5: 9 2

j J ‘t

THESE SIZES MARKED ON GAUGE %Jj’_

-___--____________--------

-_----__-_-_-____-_-------

..!.i ._

““1 ---

_---_“7T~~_ ____ -__ ______ _____-__-------_.

,_., ___--__-_____-____---------------------

1.6 mm THICK MS SHEET ROLLED OVER 8mm ($ BAR

Sll dimensions in millimetres.

FIG. 2 TEICKXESS GAUGE

_.



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Elongated Particles

Particles whose longest dimension is greater than 1.8 times itsmean dimension.

Elongation IndexIts percentage of that mass of aggregate whose longestdimension is greater than 1.8 times its mean dimension..Applicable to particles greater the 6.3mm size



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Length Guage



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IS : 2386 ( Part I ) - 1963

the gauge or sieve shall be of the dimensions specified in co1 3 of Table V for the appropriate size of material.

TABLE V DIMENSIONS OF THICKNESS AND LENGTH GAUGES

(Clauses 4.2, 4.4.1, 4.4.2, 5.2 and 5.4.1 )

SIZE OF AQQBE~ATE r------- h______-__~ Pass$gTFeough Retained On

i IS Sieve

(1) (2)

THICENE~S GAUC+E*

(3)

mm

LENQTH GanaEt

(4)

mm

63-mm 50-mm 40-mm 31*&mm 25-mm 20-mm 16-mm 12.5-mm 1 O-mm

50-mm 40-mm 25-mm P&mm 20-mm 16-mm 12%mm lo-mm 6.3-mm

33.90 27.00 19.60 16’95 13’50 10.80 8’55 6’75 4.89

ST0 58’6

4;5 32.4 25% 262 14.7

*This dimension is equal to 0.6 times the mean sieve size.

tThis dimension is equal to I.8 times the mean sieve size.

4.4.3 Weighing of Flaky Material - The total amount passing the gauge shall be weighed to an accuracy of at least 0.1 percent ofthe weight of the test sample.

4.5 Reporting of Results - The flakiness index is the total weight of the material passing the various thickness gauges or sieves, expressed as a percentage of the total weight of the sample gauged.

5. DETERMINATION OF ELONGATION INDEX

5.1 Object - This method of test lays down the procedure for determin- ing the elongation index of coarse aggregate.

NOTE - The elongation index of an aggregate is the percentage by weight of particles whose greatest dimension ( length ) is greater than one and four-fifths times their mean dimension. Normally, the properties of interest to the engineer are sufficiently covered by the flakiness or angularity tests. The elongation test is not applicable to sizes smaller than 6.3 mm.

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Test Procedure



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Test Procedure

I Take the aggregate passing form specific sieve sizes suchthat you get minimum 200 particles for a particular size.

I Take weights (pi ).I Pass / retain through Thickness/ length gauge.I Take the weight of passed/retained aggregates (qi ).

Flakiness/Elongation index =m∑i

piqi (1)



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Combined Flakiness Elongation Index

I Conduct the Elongation index test to the aggregates whichare passing for flakiness index.

I Take the weight which passes both the test.I Determine percentage.



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Specification IRC 111 2009



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Relevant Standards

I IS:2386-part 1



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References

P. Chakorborty and A. Das. Principles of TransportationEngineering. PHI Learning (formerly Prentice Hall ofIndia), 2003.

SK Khanna and CEG Justo. Highway engineering. NemChand & Bros, 1991.

Indian Institute of Technology Delhi


Priyansh SinghWebpage: web.iitd.ac.in/~cez138070

Questions ?

Thanks !