Sieve Analysis

 1.  Introduction

·     Purpose

The purpose of sieve analysis is commonly used to figure out the particle size distribution of unsaturated soil sample. The relative proportions of different grain sizes is very important for soil. Soil can be lead to failure or is able to carry it function due to size distribution.

·     Standard

Sieve analysis procedure follow by ASTM D 422 – Standard Test Method of Particle size Analysis of soil.

  2.  Apparatus

- Set of sieves

- Sieve Shaker

- Balance

- Cleaning Brush

- Pan

- Oven

           

  3.  Test Procedure

1.     We need to make the soil sample becomes unsaturated by placing in the oven for 24 hour.

2.     Then, we take representative soil sample from oven for our sieve analysis.

3.     Using balance and record the weight of dry soil sample. In this experiment we take 800g of soil sample.

4.     Record the weight of each sieve as well as the bottom pan to be used in the analysis.

5.     Each sieves have to be clean.

6.     Pour the 800g soil sample into set of sieves. Set of sieves has to be arrange from top which has larger to smaller diameter size at bottom. Also, we place a pan to collect fined grain soil that go pass through smallest sieve (#200).

7.     Activate sieve shaker machine with 10 minutes time limit. Make sure we place and tighten a belt to the set to sieves to avoid any accident occur unintentionally during shaking time.

8.     Record the weight of each sieve with its retained soil.

9.     Weight the bottom pan.

    4.  Data Analysis and Calculation

Mass Retained (gr)

          In order to obtain mass retained soil we take the weight of soil retained on each sieve subtracting with the weight of empty sieve.

Mass Retained (gr) = Weight of soil on each sieves – Weight of each empty sieves

Sieve Number	Weigh of Sieves	Weight of sieves + soil retained	Mass Retained (gr)
4	382	399	17
10	333	423	90
20	331	562	231
40	320	512	192
80	316	526	210
100	321	349	28
200	309	334	25
Pan	239	245	6
		Mass Dry Soil	800g

% Retained

In order to obtain % retained soil we take the weight mass retained in each sieves divide by sum of total mass retained then multiply by 100%.

Σ(% Retained)

% Finer

In order to obtain % Finer soil we substance 100% with each sieves                                     .

 

% Finer = 100% - each sieves

Data Analysis

Sieve Number	Opening (mm)	Mass Retained (gr)	% Retained		% Finer
4	4.75	17	2.13	2.13	97.88
10	2	90	11.25	13.38	86.63
20	0.85	231	28.88	42.25	57.75
40	0.425	192	24.00	66.25	33.75
80	0.18	210	26.25	92.50	7.50
100	0.15	28	3.50	96.00	4.00
200	0.075	25	3.13	99.13	0.88
Pan		6	0.75	99.88	0.13
	Dry Soil	800g

  5.  Conclusion

According to value of Cu and Cc from calculation above, we can identify the soil clearly whether it is classified in well graded, poorly graded or gap graded soils. Cu value 4.5 which is higher than 4 indicate a wider assortment of particle size. A soil that has uniformity coefficient of >4 is described as a well graded soil. In addition, the value of coefficient of curvature is 0.5 which is <1 which indicate gap graded soil.

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Reference: www.uta.edu/ce/geotech/lab/Main/sieve/index.htm

Author: Nararoth Theng

Publish date: 29 March 2015

Phnom Penh, Cambodia