Sieve Analysis Report (CIVIL ENGINEERING)

1.0  OBJECTIVE

The sieve analysis determines the grain size distribution curve of soil sample by passing them

through a stack of sieves of decreasing mesh opening sizes and by measuring the weight retained on

each sieve. The sieve analysis is generally applied to the soil fraction larger than 75m

2.0  INTRODUCTION

Sieving can be performed in either wet or dry conditions. Dry sieving is used only for soil with a negligible amount of plastic fines such as gravels and clean sand, where as wet sieving is applied to soils with plastic fines. According to the British Standard, dry sieving may be carried out only on materials for which this procedure gives the same result as the wet-sieving procedure. This means that it is applicable only to clean granular materials, which usually implies clean sandy or gravelly soils that is, soils containing negligible amounts of particles of silt or clay size. Normally the wet-sieving procedure should be followed for all soils. If particles of medium gravel size or larger are present in significant amounts, the initial size of the sample required may be such that riffling is necessary at some stage to reduce the sample to a manageable size for fine sieving.

3.0 THEORY

(BS1377 : Part 2: 1990:9.3), Sieving can be performed in either wet or dry conditions. Dry sieving is used only for soil with a negligible amount of plastic fines such as gravels and clean sands. Where as wet sieving is applied to soils with plastic fines. According to be Bristish Standard. Dry sieving may be carried out only on materials for which this procedure gives the same result as the wet-sieving procedure. This means that it is applicable only to clean granular materials. Which usually implies clean sandy or gravelly soils that is. Soils containing negligible amount of particles of silt or clay size. Normally the wet-sieving procedure should be followed for all soils. If particles of medium gravel size or larger are present in significant amounts. The initial size of the sample required may be such that riffling is necessary at some stage to reduce the sample to a manageable size for fine sieving.

BS1377:1990. Allows either wet or dry sieving to be used. But the wet method is preferred. After oven drying, the test sample mass is determine before being separated into two part, the first comprises that retained on a 20mm sieve and the second that passing 20mm. that greater than 20 mm is dry sieve, while that smaller is wet sieve prior to being re-sieved dry. The sieves used are generally chosen from the range (in mm) of 75, 63, 50, 37.5, 28, 20, 14, 10, 63.5, 3.35, 2, 1.18, 06, 0.425, 0.3, 0.212, 0.15 and 0.063. the mass retained on each sieve is recorded. From which the percentage of the sample passing each sieve can be calculated. Material passing the 63 micron (0.063mm) sieve is retained for a fine particle analysis. If the amount justifies the further test. The combined result of the coarse and fine analysis are plotted on a semi-logarithmic graph of the form show in figure 1.0 to give the particle size distribution curve.

4.0 APPARATUS 

1. Series of standard sieves with opening ranging from 7.5cm to 75m including a cover plate and bottom pan.

2. Test sieve having the following aperture size 2.36mm, 1.18mm, 0.600mm 0.425mm,0.300mm, 0.212mm, 0.150mm and 0.075mm.

3. Mechanical sieve shaker

4. Balances sensitive 0.5g.

5. Soft and hard wire brush.

5.0 PROCEDURE

1.      The sample was oven drive to than the weight was measured.

2.      A stack of sieves that suitable to the soil were selected then it has been tested.  Arranged  we stack of six or seven sieves was generally sufficient for most soil and applications. The top sieves soil was have an opening slightly larger than the largest particles. The stack of sieves were arranged then the largest mesh was opened at the top then the smallest was at the bottom.

3.      A pan was attached at the bottom of e sieves stack. The sample were pour on the top sieve. More cover plate were added to avoid dust and loss of particles while shaking.

4.      The stack of sieves were placed in the mechanical shaker and shake for about 10 minutes until to additional shaking does not produce appreciable changes in the amounts of material retained in each sieve.

5.      The stack of sieve were removed from the shaker. Firstly with the top sieve, the content were transferred to a piece of paper. The sieve were empty with carefully without losing any material  and a brush were used to remove grains stuck in its mesh opening. The weight of soil that retained in each sieve were measured and the corresponding sieve mesh opening and number were noted.

6.      Step 5 was repeated for each sieve. Using a preliminary check, the weights retained on all the sieves and the bottom pan was added, and their sum was compared to the initial sample weight. Both weights were within about 1% because the difference is greater than 1% too Much material was lost and weighing and or sieves were repeated.

6.0 COMMON ERROR

According to Rolling’s and Rolling’s (1996), common laboratory error associated with the sieve analysis include:

1.      Failure to separate agglomerations of material (such as clay clods) into individual grains during the washing and mechanical sieving process.

2.      Loss of material during testing.

3.      Overloading of sieves.

4.      Broken or distorted sieves

5.      Inadequate shaking of sieves 

7.0 EXAMPLE AND QUESTION:

Example :

Data : Total mass of dry sample 115.5g

Sieve BS (mm)	Mass Retained (g)	Mass Passing (g)	% finer by weight
5.00 2.00 1.180 0.600 0.425 0.300 0.212 0.150 0.63 Pan	0.0 0.0 0.5 25.7 23.1 22.0 17.3 12..7 6.9 2.3	0.0 115.5 110.0 84.3 61.2 39.2 21.9 9.2 2.3	0.0 100 95 73 53 34 19 8 2

Total mass = 115.5 g

Lost           =        0

From the data, plot a graph partial size versus percentage passing.

8.0 DATA

Sieve no. size (mm)	Mass of sieve (g)	Mass of plain sieve (g)	Mass retained (g)	Mass passing (g)	Cumulative percentage passing (%)
2.360	540	530	10	490	98%
1.180	425	360	65	425	85%
0.600	445	325	120	305	61%
0.425	360	285	75	230	45%
0.300	345	280	65	165	33%
0.212	330	275	55	110	22%
0.150	305	270	37	73	14.6%
0.075	325	255	70	3	0.6%
Total			497

% Passing                = 100 -  % Retained.

Mass of dry sample = 500 gram

Plot particles size distribution chart.

Cu = d60 / d10 = 5.8

Cu = d = 1.26

Sieve no. size (mm)	Mass of sieve (g)	Mass of plain sieve (g)	Mass retained (g)	Mass passing (g)	Cumulative percentage passing (%)
2.360	540	530	540-530=10	500-10=490	98%
1.180	425	360	425-360=65	490-65=425	85%
0.600	445	325	445-325=120	425-120=305	61%
0.425	360	285	360-285=75	305-75=230	45%
0.300	345	280	345-280=65	230-65=165	33%
0.212	330	275	330-275=55	165-55=110	22%
0.150	305	270	305-270=37	110-37=73	14.6%
0.075	325	255	325-255=70	73-71=3	0.6%
Total			497

How to calculate cumulative percentage passing (%)

Formula :   mass passing    x 100

                 Mass of dry sample

Sieve no size = 2.360mm

Cumulative percentage passing (%) : 490 x 100

                                                            500

                                                          : 98%

Sieve no size = 1.180mm

Cumulative percentage passing (%) : 425 x 100

                                                            500

                                                          : 85%

Sieve no size = 0.600mm

Cumulative percentage passing (%) : 305 x 100

                                                            500

                                                          : 61%

Sieve no size = 0.425mm

Cumulative percentage passing (%) : 230 x 100

                                                            500

                                                          : 45%

Sieve no size = 0.300mm

Cumulative percentage passing (%) : 165 x 100

                                                            500

                                                          : 33%

Sieve no size = 0.212mm

Cumulative percentage passing (%) : 110 x 100

                                                            500

                                                          : 22%

Sieve no size = 0.150mm

Cumulative percentage passing (%) : 73 x 100

                                                            500

                                                          : 14.6%

Sieve no size = 0.075mm

Cumulative percentage passing (%) : 3 x 100

                                                            500

                                                          : 0.6%

9.0 DISCUSSION

            Sieve analysis is the process of dividing a sample of aggregate into fraction of the same size. The purpose of doing this analysis is to determine the grading or size distribution of the aggregate which is important to find out whether the aggregate pile we are studying is good for the mix or not. The grading of the aggregate usually effects on the workability of the fresh concrete. The aggregate of interest is thrown into a series of sieves nested in order with the smallest at the bottom, and after shaking the mass of retained aggregate in each sieve is calculated. The aggregate we use in our experiment should be representative to the pile we obtained it from, so we can’t just take the mass we need for the experiment arbitrary because this arbitrary specimen might not contain a certain size of the aggregate. For that reason the Quartering Method is used, this method involves taking a big amount of aggregate from the pile of interest (more than the amount we need) and then divide them into quarters or halves till we gain the amount we need for the experiment. A sieve have square opening and are usually constructed of wire mesh. In this analysis certain sizes of sieves should be used to get a desired and accepted results, these sieves are determined by ASTM E – 11 as mentioned in the specifications. The nested sieves we use every next sieve (starting from the smallest) is twice the size of sieve preceding it. After sieving the specimen, we calculate the retained mass in each sieve and a table is made and the grade curve is drawn. The table should contain the following columns: Sieve size, Mass retained, Percentage retained, Cumulative percentage passing and Cumulative percentage retained. The percentage retained can be gained by the following formula:

                         mass retained \ total mass  x  100%

            The grading curve is drawn by using the information of the table. The grading curve represents the relationship between the Sieve size (the abscissa) and the Cumulative percentage passing (the ordinates), we use the logarithmic scale to plot the graph. The standards usually give an Upper limit graph and a lower limit graph so that our graph should be between these 2 graph to be usable in mixes. The graph is drawn be drawing line segments between the points. Fineness Modulus is a measure to the grading of an aggregate pile, and it is used to compare aggregate that are gained from the same source. It can be defined as the sum of the Cumulative percentage retained on the sieves of the standard series divided by 100. The sieve analysis can be done in two methods, a wet method and a dry method, but as the wet method takes more time we have done the dry method.

10.0 CONCLUSION

            The aggregate we studied consists of coarse aggregate mainly; I noted that from the fineness modulus. From the Grading graph we note that the aggregate we have tested are not good for using in mixes, as the graph doesn’t lie between the upper limit and the lower limit.