# TO DETERMINE THE FINENESS MODULUS AND AVERAGE SIZE OF GIVEN SAMPLE OF CONCRETE AND FINE AGGREGATE

**OBJECTIVE**

** TO DETERMINE THE FINENESS MODULUS AND AVERAGE SIZE OF GIVEN SAMPLE OF CONCRETE AND FINE AGGREGATE****1 APPARATUS REQUIRED **

- IS sieves of size 80 mm ,40 mm,20 mm,10 mm,4.75 mm,2.36 mm,1.18 mm,600 micron,300 micron,and 150 micron.
- mechanical /semi mechanical sieve shaker.
- weighting balance

2 **THEORY**** ** sieve analysis is the operation of dividing a sample of aggregates into various fractions each consisting of particle of same size .the sieve analysis is conducted to determine the particle size disatribution in a sample of aggregate ,which we can call gradation.

a convenient size of expressing the gradation is one which the consecutive sieve opening are constantly doubled ,such as 10 mm, 20 mm ,40 mm etc. under such a system ,employing a logarithmic scale ,lines can be spaced at equal interval to represent the sucessive size. fine aggregate is sand and course aggreggates is generally broken stone used in concrete .aggregate retained on 4.75 mm sieve (IS) is called coarse aggregate and passing through it is called fine aggregates.

fineness modulus (FM) of aggregate is an inde number used to indicate the average size of particles in aggergates . the FM is found as sum of cumulative % (C%) of the masses of aggregate retained on a set of IS sieves ( 80 mm ,40 mm,20 mm,10 mm,4.75 mm,2.36 mm,1.18 mm,600 micron,300 micron,and 150 micron.) and divided by one hundred . mathmatically,

F.M=(ଽC %/100)

F.M is looked as a weighted average size of a sieve on which the material is retained , the sieve being counted from finest sieve. for example F.M=4 means that the forth sieve (1.18 mm)

size is average size of the aggregate . higher value means coarser and vice versa .F.M is limited to 2.0-3.5 and 5.5-8.00 for fine aggregates & coarse aggregates respectively.

3 **PROCEDURE**

the following procedure was done for sieve analysis:

- at first 5 kg of sample of coarse and 2 kg of fine aggregates was taken.
- then the set of 10 IS sieves was prepared placing coarser sieve top and finer sieve lower ie 80 mm ,40 mm,20 mm,10 mm,4.75 mm,2.36 mm,1.18 mm,600 micron,300 micron,and 150 micron.
- coarse & fine aggregates were sieve separately for not less than 2 minutes mechanically.
- the weight of aggregates retained on each sieve was weighted by using weighting machine

**4 OBSERVATION AND CALCULATION:**

wt of sample of coarse aggregate taken (Wc)=5 kg

wt of sample of fine aggregate taken (Wf)=5 kg

**5 RESULT**

the fineness modulus and average size of giver sample are as follows

for coarse aggeregate :FM =8.89

average size: 20 mm

for fine aggregate :FM=5.34

average size:2.36 mm**6 CONCLUSION**

THE FINENESS MODULUS AND AVERAGE SIZE OF GIVEN SAMPLE OF CONCRETE AND FINE AGGREGATE WAS DETERMINED**7 SUGGESTION****Q**