EXPERIMENT NO-6

OBJECT: Sieve analysis of the given fine aggregate and determine the fineness modulus

 THEORY:

Fine aggregate is the sand used in mortars. .The coarse aggregate unless mixed with fine aggregate serves no purpose in cement works .the size of fine aggregate is limited to a maximum of 4.75 mm gauge.

FINENESS MODULUS: Fineness modulus is only a numerical index of fineness, giving some idea of the mean size of the particles in the entire body of the aggregate. To a certain extent it is a method of standardization of the grading of the aggregate. It is obtained by adding the percentage weight of material retained in each of the standard sieves and dividing it by 100.

To object of finding the fineness modulus is to grade a given aggregate for the most economical mix and workability with minimum quantity of cement .Certain limits of fineness modulus for fine coarse aggregates are given in the table below and a sample under test should satisfy these results so that the aggregate may give good workability under economical conditions.

LIMIT OF FINENESS MODULUS 

Maximum size of aggregate	Fineness modulus
	Minimum	Maximum
Fine Aggregate	2	3.5
Coarse aggregate 20mm	6	6.9
Coarse aggregate 40mm	6.9	7.5
Coarse aggregate 75mm	7.5	8.0

If the test aggregate gives higher fineness modulus the mix will be harsh and if on the other hand gives a lower fineness modulus it gives uneconomical mix.

APPARATUS:

Indian standard test sieves, weighing balance ,sieve shaker etc .

Size of sieves to be used.

(I) for fine agggregate- 4.75mm, 2.36mm, 1.18mm, 600 microns, 300microns ,150microns .

PROCEDURE:

FINE AGGREGATE

(i)Take one kg of sand from the laboratory sample

(ii)Arrange the sieves in order of IS sieves no’s 480, 240, 120, 60, 30 and 15, Keeping sieve no.480 at the top and 15 at the bottom and cover the top.

(iii)Keep the sample in the top sieve no.480.

(iv) Carry out the sieving in the set of sieves for not less than 10 minutes .

(v) find the weight of sample retained in each sieve.

(vi) Tabulate the values in given tabular column .

GRAPH

Draw a graph with sieve opening to log scale on the X-axis and % finer on Y-axis .The curve is called a grading curve.

CALCULATION:

FINE AGGREGATE

 Fineness modulus (Sum of cumulative % wt retained /100) =

RESULT S:

FINE AGGREGATE

 Fineness modulus =