soil lab-water content - Determination of Water Content 2.1...

Info icon This preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 6
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Determination of Water Content 2.1 Introduction ASTM Standard: D—2216 Most laboratory tests in soil mechanics require determination of the water content. Water content is defined as weight (or mass) of water present in a given soil mass (2 1) W : weight (or mass) of dry soil Water content is usually expressed in percent. For better results, the minimum size of most soil specimens should be approximately as given in Table 2—1. These values are consistent with ASTM test designation D-2216. 2.2 Equipment 1. Moisture can(s)——Moisture cans are available in various sizes [for example, 2 in. (50.8 mm) in diameter and 7/8 in. (22.2 mm) high; 3.5 in. (88.9 mm) in diameter and 2 in. (50.8 mm) high]. 2. Oven with temperature control—For drying, the oven temperature is generally kept at 110 :i: 5°C. A higher temperature should be avoided to prevent the burning of organic matter in the soil. 10 SOIL MECHANICS LABORATORY MANUAL Table 2—1. Minimum Size of Moist Soil Samples to Determine Water Content Maximum Particle Size in Minimum Mass of Soil (mm) . Soil Sample [91 Table 2—2. Required Readability of Balance Size in Soil [mm] m n .3- m m w y of the balance to be used is given in Table 2—2 (ASTM, ture cans and a balance having a readability of Readability of Balance [9] 3. Balance—The readabilit 2010). Figure 2-1 shows some mois 0.01 g. Determination of Water Content 11 Figure 2-1. Moisture cans and balance. 2.3 Procedure 1. Determine the mass (g) of three empty moisture cans plus their caps, M1, and also record the numbers (lines 1 and 2 of Table 2—3). 2. Place samples of representative moist soil in the cans. Close the cans with their caps to avoid loss of moisture. 3. Determine the combined mass (g) of the closed cans and moist soil, M2 (line 3 of Table 2—3). 4. Remove the caps from the top of the cans and place them at the bottom (of the cans). 5. Put the cans (Step 4) in the oven to dry the soil to a constant weight. In most cases 24 hours of drying is enough. 6. Determine the combined mass (g) of the dry soil samples plus the cans and their caps. M3 (line 4 of Table 2—3). 2.4 Calculations 1. Calculate the mass of moisture, M2 ~— M3 (line 5 of Table 2—3) 2. Calculate the mass of dry soil, M3 + M] (line 6 of Table 2—3) 3. Calculate the water content (line 7 of Table 2~3), M —M w(%) = fl x 100 (2.2) 3- l 4. Calculate the average of the three water contents determined in Step 3 (see bottom of Table 23). Report the average water content to the nearest 1% or 0.1%, as appropriate, based on the size of the specimen. 12 SOIL MECHANICS LABORATORY MANUAL Table 2-3. Determination of Water Content DescriptIOn of soii—me— Sample no. __—5f——— Location Tested by___——__—________ Date 1. Can no. 42 31 2. Mass ofcan, M1 (g) 1— 17.31 18.92 _r. 3. Mass of can + wet soil, M2 (g) .‘ 43.52 52.19 39.43 4. Mass ofcan+dry soil, M3 (g) 39.86 47.61 36.13 —T 5. Mass of moisture. M2 — M3 (g) 3.66 4.58 3.30 6. Mass of dry soil. M3 r M; (g) 22.55 28.69 20.06 M —M 16.2 16.0 16.5 7. Water content, w (%) = ~—3———3— x 100 M3 — M1 Average water content w __1542_% A complete sample calculation of water content is given in Table 2—3. 2.5 General Comments 1. Most natural soils that are sandy and gravelly in nature may have water contents of up to about 15—20%. In natural fine—grained (silty or clayey) soils, water contents of up to about 50-80% can be found. However, peat and highly organic soils with water contents of up to about 500% are not uncommon. Typical values of water content for various types of natural soils in a saturated state are shown in Table 2—4. 2. Some organic soils may decompose during oven drying at 110 :i: 5°C. This oven drying temperature may be too high for soils containing gypsum, as this material dehydrates slowly. For such soils a drying temperature of 60°C is more appropriate. 3. Cooling the dry soil after oven drying (Step 5 of Section 2.3) in a desiccator is rec- ommended. A desiccator, as shown in Fig. 2—2, is a glass container that contains a desiccant, such as anhydrous silica gel, that keeps the air within the glass container dry. Determination of Water Content 13 Table 2—4. Typical Values of Water Content in a Saturated State Natural Water Content in aSMmamdSmm[%l 25—30 Glacial till i. s3} {3 f xi .. -, ‘1, fie '\ .1; i a: " 1 ' ‘ n ‘ ~anmm :V‘ r x ) a. Figure 2—2. A desiccator. [Courtesy of N. Sivakugan. James Cook University. Australia.) him —:.w~“ :«va-ii‘hfifffiéfl- ‘ ' ” 14 SOIL MECHANICS LABORATORY MANUAL 2.6 Laboratory Report The laboratory report should contain the following: Cover page Equipment used Description of test procedure Results—data sheet and sample calculations Sources of error, if any ...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern