Fineness of fine aggregates perfect (1)

TEST OF AGREGATES

1. Tests for sand and fine aggregate
AIM: To determine the particle size distribution of fine aggregates by sieving.
REFERENCE: IS 2386-1 (1963) - Methods of test for aggregates for concrete and IS
383 (1970): Specifications for coarse and fine aggregate from natural sources for
concrete.
SIGNIFICANCE:
Aggregate most of which passes 4.75 mm IS Sieve and contains only so much
coarser material such as natural sand, crushed stone sand and crushed
gravel sand.
As far as possible, flaky, scoriaceous and clongated pieces should be
avoided
The concrete mix design depends on the gradation of aggregates in a given
sample.
The sieve analysis of aggregate determines the % of sizes of aggregates in
the sample and hence packing as well as mix design ratios for a concrete
mix can be derived.
The sieve analysis of aggregates shows the gradation curve of various sizes of
aggregates in the given sample
IS Sieve
designation
Grading Zone
1
(in %)
Grading Zone 2
(in%)
Grading Zone 3
(in %)
Grading ZONE
4
(in %)
10 mm 100 100 100 100
4.75 mm 90-100 90-100 90-100 95-100
2.36 mm 60-95 75-100 85-100 95-100
1.18 mm 30-70 55-90 75-100 90-100

2. 600 mu 15-34 35-59 60-79 80-100
300 mu 5-20 8-30 12-40 15-50
150 mu 0-10 0-10 0-10 0-15
NOTE:
·For crushed stone sands, the dermissible limit on 150-micron IS Sieve is
increased to 20 percent. This does not affect the 5 percent allowance
permitted in order to sieve size
·Fine aggregate complying with the requirements of any grading zone in
·This table is for concrete but the quality of concrete produced will
depend upon a number of factors including proportions.
·Where concrete of high strength and good durability is required, line
aggregate conforming to any one of the four grading zones may be
used, but the concrete mix should be properly designed. As the
progressively finer, that is, from Grading Zones I to 4, the ratio of
aggregate grading & coarse aggregate should be progressively reduced.
·The most suitable fine to coarse ratio to be used for any particular mix will,
however, depend upon the actual grading, particle shape and surface
texture of both fine and coarse aggregates.
·It is recommended that fine aggregate conforming to Grading Zone IV
should not be used in reinforced concrete unless tests have been made
to ascertain the suitability of proposed mix proportions.

3. APPARATUS:
SR. NO.APPARATUS SPECIFICATION
1 Sieves Conforming to IS: 460- 1962
2.36 mm
1.18 mm
600 mu
300 mu
150 mu
75 mu
2Balance Maximum capacity: 20 Kg; Minimum
capacity: 0.002kg
3 Brush Fine camel hair brush
MATRIALS :
Fine aggregrate ( particle size =< 4.75 mm)
SAMPLING AND SELECTION OF TEST SPECIMEN :
The sample shall be brought to an oven dry condition before weighing and
sieving.This may be achieved by heating at a temperature of 100 to 110
°C in the oven for 24 hrs.
The air-dry sample shall be weighed and sieved successively on the
appropriate sieves starting with the largest
Care shall be taken to ensure that the sieves are clean before use

4. PROCEDURE :
Sieve the aggregate using the appropriate sieves (80 mm, 40 mm, 20 mm, 10
mm, 4.75 mm, 2.36 mm, 1.18 mm, 600 micron, 300 micron & 150 micron)
The shaking shall be done with a varied motion, backwards and forwards, left
to right, circular clockwise and anti-clockwise. Material shall not be forced
through the sieve by hand pressure. Lumps of fine material, if present, may
be broken by gentle pressure
Light brushing with a brush may be used on the 150-micron and 75-micron IS
Sieves to prevent aggregation of powder and blinding of apertures.
On completion of sieving, the material retained on each sieve, shall be
weighed.
Record the weight of aggregate retained on each sieve.
Calculate the cumulative weight of aggregate retained on each sieve.
Calculate the cumulative percentage of aggregate retained.
Add the cumulative weight of aggregate retained and divide the sum by
100. This value is termed as fineness modulus
OBSERVATION TABLE
SIEVE
NO.
SIEVE
SIZE
(mm)
RETAINED
ON EACH
SIEVE (%Wt)
CUMULATIV
E
PERCENTAG
E RETAINED
PASSING
THROUGH
(%Wt)
GRADING
LIMITS/
REMARKS
1 4.75
mm
5.76 5.76 94.24
2 2.36
mm
9.135 14.89 85.11
3 1.18
mm
7.81 22.70 77.3
4600 mu 11.61 34.305 65.65
5300 mu 49.515 83.865 16.14
6150 mu 11.54 95.405 4.595

5. 775 mu 4.155 99.56 0.44
FINENESS MODULUS = (5.76+4.89+22.7+34.305+83.865+95.405 + 99.56)/100 =
346.485/100
=3.46
RESULT
Fineness modulus of fine aggregate is 3.46.

6. 775 mu 4.155 99.56 0.44
FINENESS MODULUS = (5.76+4.89+22.7+34.305+83.865+95.405 + 99.56)/100 =
346.485/100
=3.46
RESULT
Fineness modulus of fine aggregate is 3.46.