Report To: Mr. Wing Pak, P. Eng. Civil Engineering, School of Technology Niagara College Canada Materials II – CIVL 1356 Lab Report No. 2

3 Part Lab

Part A – Sieve Analysis Part B - Hydrometer Analysis Part C - Atterberg Limits Test

Submitted By: Dean Pilon, Student No. 4172383, 100% Andrew Mitchell, Student No. 4177222, 100% Andrew Mazzotti, Student No. 4118628, 100% Submission Date: 2012/10/16

  

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Summary:

This lab was conducted to gain a better understanding and appreciation of soil –

more specifically, its’ composition and the classification process. This was

accomplished by performing a sieve and hydrometer analysis test, collecting the

results, and generating a particle size distribution curve. The soil used in these

labs was obtained from the sample of soil tested in labs 1 and 2.

In the first part of this lab (Part A) the soil sample analyzed using sieves. This

process determined the particle size distribution for particles larger than the No.

100 sieve.

The second portion of the lab (Part B) focused on the particles passing through

the No. 100 sieve. Using these particles, a hydrometer analysis was conducted

to determine the particle size distribution for the soil.

After collecting all the data from the sieve and hydrometer analysis tests, a

particle distribution curve was generated for the soil sample.

For the third portion of the lab (Part C) a soil was put through the Atterberg Limits

test. This test was utilized to determine the plastic limit and liquid limit of the soil

sample.

After combining the results from the three portions of this lab, it was determined

that the soil sample was composed of silty sands (sand silt mixtures). This was

accomplished using the Unified Soil Classification System.

Soil classifications differed between Lab 1 (OH, OL) and Lab 2 (SM). This result

was due to more thorough and accurate testing completed in lab 2.

  

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Table of Contents

Introduction Page 4

Theory Page 5

Procedure Page 7

Observations Page 7

Discussion of Results Page 10

Conclusions Page 12

Figures

Figure 1 Mechanical Method Results Chart Page 6

Figure 2 Hydrometer Results Chart Page 7

Figure 3 Particle Size Analysis Chart Page 9

Figure 4 Atterberg Limits Test Results Chart Page 10

Figure 5 USCS Plasticity Chart Page 10

Figure 6 USCS Flow Chart Page 11

Figure 7 USCS Flow Chart Page 12

  

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Introduction:

Part A The purpose of this lab is to perform a sieve analysis of the soil collected in lab 1 to

determine the particle size distribution for particles larger than the No. 100 sieve. The

results will be used to complete a particle size distribution curve to classify the sample

of soil by the Unified Soil Classification System. This test is important in the industry

since it helps in identifying and classifying soil types, determining the suitability of a soil

for certain uses, predicting soil-water movement, and determining the soil’s

susceptibility to frost action.

Part B

The purpose of this lab is to learn and apply techniques which are suitable to classify

samples of soil. In this lab a hydrometer analysis test will be performed on the soil

which passed through the 100 sieve in the previous lab. Using the results from the

previous lab and the hydrometer analysis, a distribution curve can be completed and

used to classify the type of soil used. The soil sample will be classified according to the

Unified Soil Classification System. This process is utilized to gain a better

understanding of the type of soil in an area.   Determining the type of soil for construction

sites is considered vital information since the type of soil can dramatically alter the cost

and design of a structure.

Part C

The purpose of this lab is to use the Atterberg Limits test to determine the plastic limit

(PL), liquid limit (LL), and plasticity index of the soil (PI) collected in Lab 1. These soil

index properties, along with the results from Labs 3 and 4, will be used to classify the

soil according to the Unified Soil Classification System based on the laboratory

classification criteria. Liquid and Plastic limits are utilized during the classification of

soils types, the prediction of maximum density in compaction studies, and estimation of

settlements of structures under loads due to soil consolidation.

  

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Theory:

In this lab a sieve analysis was performed to determine the particle size distribution for

particles larger than the No. 100 sieve. Sieve analysis test depends upon gravity and

agitation of the sample to segregate the particles onto the various sieves. Data was

taken to see what % was retained and what % passed through the sieve. This

mechanical method will not work on material which is finer than the No. 200 sieve.

Material finer than the No. 200 sieve must be analyzed for grain-size distribution by a

wet analysis known as the hydrometer method.

Also a hydrometer analysis was done to determine the particle size distribution for

particles passing through the No. 100 sieve. “The hydrometer analysis is based on

Stokes’ law, which relates the terminal velocity of a sphere falling freely through a fluid

to the diameter of the sphere...According to Stokes’ law; larger spheres will have a

higher terminal velocity, and, thus, in a suspension of particles, will fall to the bottom

sooner. The hydrometer is used to determine the percentage of dispersed soil particles

remaining in suspension at a given time.” Soils in Construction, W.L. Schroeder, S.E.

Dickenson & Don C. Warrington, 5th Edition, Pearson Prentice Hall. These test are

done to classify the soil in a given identification system, Determine the suitability of a

soil for use in road, airfield, and embankment construction. Predict soil-water movement

(if permeability test results are not available), and determine the soil’s susceptibility to

frost action.

An Atterberg Limits Test was also performed to determine the plastic limit (PL), liquid

limit (LL) and plasticity index of the soil (PI) collected. This test is also used to classify

the soil type. The liquid limit is the water content at which soil is on the verge of

becoming fluid, and plastic. The plastic limit is tested when turned to a thread of soil just

cracks or crumbles when it is rolled down to a diameter of 1/8 to test the water content

at which soil is non-plastic. Plasticity Index = Liquid Limit – Plastic Limit

  

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Procedure: For procedure please reference the documents for Lab 3, Lab 4, and Lab 5 from CIVL

1356 at Niagara Collage.

Observations: Part A The sample used in this test appears to be comprised of two types of soils. The sample

used for this test was a combination of both types (clayey clumps and loose fines). The

observations recorded during the sieve analysis are displayed in figure 1 below.

Furthermore, a particle size analysis chart displaying the results from the sieve (blue

line) and hydrometer test (green line) can be viewed in figure 3 on page 8.

 

Figure 1   Mechanical Method Results Chart

  

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Part B

The observations recorded during the hydrometer test are displayed in figure 2 below.

While conducting this test the sample developed approximately ¼ inch of foam at the

top of the liquid. As a result, it was difficult to get an exact reading of both the

hydrometer and thermometer during the first 60 minutes of testing. Therefore, there

may be some discrepancy with the results. Figure 3 is a particle analysis chart

displaying information from both Part A (blue line) and Part B (green line).

 

Figure 2   Hydrometer Results Chart

  

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Figure 3   Particle Size Analysis Chart

Part C

The data collected from the Atterberg Limits test is located in figure 4 below. During the

testing the soil emitted a strong earthy smell as water was added to the sample. As

figure 4 indicates, the plastic limit was 39.9, the liquid limit was 50.25, and the plasticity

index was 10.95. When plotted out on the plasticity chart for the Unified Soil

Classification System the results are located below the “A line” on the graph (see figure

5).

  

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Figure 4   Atterberg Limits Test Results Chart

 

Figure 5    USCS Plasticity Chart

  

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Discussion of Results:

The results collected from the 3 Parts of this lab can be used to classify the soil sample

by means of the Unified Soil Classification System flow chart (Figure 6 and Figure 7).

Since the weight of more than 50% of the soil was above the #200 sieve (Figure 3) and

more than 50% of the course fraction is larger than the #4 sieve (Figure 3), the sample

is a “Sand” mixture (Figure 7). Furthermore, since the percentage of the sample

passing through the 200 sieve was greater than 12% (figure 3) and the liquid limit and

plasticity index recorded below the “A line” (figure 5), the soil receives a “SM”

designation according to the Unified Soil Classification System - meaning the soil is

composed of silty sands (sand silt mixtures).

 

Figure 6   USCS Flow Chart

  

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Figure 7   USCS Flow Chart

In the previous Lab it was determined that this soil sample was determined to be

organic in nature and consist of two different types of soil. It was believed that the

sample was composed of “OL” (organic silts and organic silt clays of low plasticity) and

“OH” (organic clays of medium to high plasticity). This outcome differs from results of

concluded from this lab (“SM” silty sands). This variance is most likely due to the fact

that two separate tests were not conducted on the two types of soils in lab 1. This very

easily could have resulted in a completely different classification since this lab combined

both types of soil in all the testing completed. Furthermore, in lab 1 it was determined –

by visual inspection – that more than 50% of the soil would pass through the #200

sieve. This was not the case (figure 3 illustrates only 22% passing) and as a result the

outcome would be altered.

  

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Conclusion:

In conclusion, through use of the Mechanical Sieve Analysis test, Hydrometer test, and

the Atterberg Limits test, it was determined that the soil used for both lab 1 and 2 was

comprised of a silty sand (USCS designation of “SM”). Differences between Lab 1’s

results and Lab 2’s results were due to more thorough and accurate testing completed

in Lab 2 – specifically the testing of both types of soil contained in the sample and a

more accurate testing of the % of soil passing through the #200 sieve.

 

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