Shape test (Lab)
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Transcript of 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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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
_--
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
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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Flakiness and Elongation Test4th February 2015
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Test Procedure
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Flakiness and Elongation Test4th February 2015
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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)
Pavement Material Lab
Flakiness and Elongation Test4th February 2015
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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.