Answ An sw ers to Ques ti on s 1. What is is the purpose of grain size analysis? The standard grain-size analysis test determines the relative proportions of different grain sizes as they are distributed among certain size ranges. 2. What is a grading curve? The size distribution curves, as obtained from coarse and fine-grained portions, can be combined to form one complete grain-size distribution curve also known as grading curve. 3. Under what conditions should you use wet wet sieving instead instead of dry sieving? Wet sieving can be used to remove fines of materials that may be difficult to sieve, prior to drying and testing a sample normally. 4. On which basis do you select the number and opening of sieves for the sieve analysis of a given soil? The size distribution is often of critical importance to the way the material perfo rms in use. A sieve analysis can be performed on any type of non-organic or organic granular materials including sands, crushed rock, clays, granite, feldspars, coal, soil, a wide rang e of manufactured powders, grain and seeds, down to a minimum size depending on the exact method. 5. A mass of volcanic ashes with highly crushable grains is brought to the laboratory. laboratory. What precaution do you take to determine its grain size distribution? Volcanic ash has the potential to cause acute and chronic respiratory diseases if the particles are sufficiently fine to enter the respiratory system. Characterization of the grain-
size distribution (GSD) of volcanic ash is, therefore, a critical first step in assessing its health hazard. 6. On what range of particle size does the sieve analysis apply? The ranges of the sieve analysis apply between 75mm (3in.) and No.200 (75Mm) sieves. 7. Is it possible to carry out sieve analysis on a sample of clay? Sieve analysis can be done wet, dry or a combination of both. A core sample is agitated and disaggregated through stacked sieves, decreasing in size from top to bottom.
Introduction
This test is performed to determine the percentage of different grain sizes contained within a soil. The mechanical or sieve analysis is performed to determine the distribution of the coarser, larger-sized particles, and the sieve analysis is used to determine the distribution of the finer particles.
Principl es of the Experiment Particle size distribution test, also known as sieve analysis test is a method used to determine the grain(granular) size distribution of soil samples. Grain-size analysis is widely used in engineering classifications of soils. The standard grain size analysis test determines the relative proportions of different grain-sizes as they are distributed among certain size ranges. The sieve analysis is a process where the grain size distribution of soil is determined. This test is done by letting a sample of soil passthrough a stack of sieves of decreasing mesh opening sizes and by measuring the weight retained on each
sieve. The main concept in this process is to retain the large particles not able to pass through the varying sieve sizes. The sieve analysis is primarily applied to soil particles with sizes from 75mm to75microns. Sieve analysis can be classified as dry sieving and wet sieving. Dry sieving is a sieving process that is used for soil with negligible number of plastic fines like gravels and clean sands. On the other hand, wet sieving is applied to soils with considerable plastic fines.
Interpr etation of Result In this experiment, the particulate nature of soil was greatly observed. It was also shown that certain classifications in soil can be done through sieve analysis. One essential thing to do in this experiment is to arrange the sieves properly. The accuracy of this experiment is very much dependent on the sieve arrangement. The arrangement of sieves must be in decreasing mesh openings from top to bottom. This is very useful to separate the particles from coarser to finer. Lastly, it was observed that for particles having sizes larger that the sieve opening to which it will be retained. On the other hand, those with smaller sizes could pass through. This phenomenon is the basic reason on how particles were separated.
Appl icati on The grain-size analysis is one process that deals in the determination of the distribution of soil types contained in a soil sample. Knowing the distribution of soil is best applied in making engineering judgements towards total soil condition. The distribution of soil components is one important soil profile applied in the field of foundation engineering. This analysis on grains is also utilized in part of the specifications of soil for airfields, roads, earth dams, and other soil embankment construction.
Conclusions Considering the graph formed by plotting the data obtained, it can be noticed that as the sieve number increases, the percent passing decreases. It can be stated that the two have inversely proportional relationship. This is also expected since as the number of sieve decreases the holes in the sieves become larger. Hence, this means that the larger particles which do have heavier weights were suspended on the sieves with smaller number.
References •
http://www.retsch.com/products/sumo/mixer-sieve-analysis-php/
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http://www.answers.com/Q/What_range_of_particle_size_does_the_sieve_analy sis_apply
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https://en.wikipedia.org/wiki/Sieve_analysis
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http://www.ivhhn.org/index.php?option=com_content&view=article&id=107
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https://www.globalgilson.com/wet-sieving-practical-guide
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https://eng.ucmerced.edu/snsjho/files/MHWG/Laboratory/Soils/Protocol/Chapter_ 9_Grain_size_analysis.pdf
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http://cemmlab.webhost.uic.edu/Experiment%206Grain%20Size%20Analysis.pdf
