INTRODUCTION The objective of this laboratory experiment is to be able to determine the particle size distribution curve of the representative sample using sieve analysis. By performing the method, sieve analysis determines the grain size distribution 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. Samples that is larger than the No. 4 Sieves (4.75mm) is used in the analysis, shaking for minutes with different sizes of mesh. Note that, as the sieve number increases the size of the openings decreases. EQUIPMENT
Mechanical Sieves Mortar and pestle Balance (with accuracy of 0.01g)
PROCEDURE 1. Collect a representative dry sample soil. Sample particles having a size that can’t pass through No.4 Sieve should be about 500g. 2. Break the sample by using mortar and pestle. 3. Weight again the sample to get a 500g. 4. Determine the weight of the sieves. 5. Placed the weighted soil in the top of sieve stack and cover with the lid. Shake for 5 minutes in order the sample pass in each sieves. 6. Weigh the sample retained in each of the sieves. DISCUSSION Mechanical analysis is the determination of the size range of particles present in a soil, expressed as a percentage of the total dry weight. Sieve analysis is a method used to determine the grain – size distribution of soils. Mechanical Sieves/ Sieves is a device used for separating wanted elements from unwanted material or for characterizing the particle size distribution of a sample, typically using a woven screen such as mesh or net or metal. Note that, there are different sizes of sieves. The representative sample dry soil is placed in the top of the sieve stack and carefully covers it with lid. Shake the stack of sieves for about 5 minutes. After shaking, weigh the sample retained on each sieves including the weight retained in the pan. All the data were recorded in a sheet and table it including the sieve no., grain size, weight retained on each sieve, cumulative weight retained, percent retained and percent finer. In making the grain size distribution curve, label its axis, x for its grain size and y for its percent finer.
