water content of soil
TRANSCRIPT
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HASHEMITE UNIVERSITYFaculty of Engineering
Civil Engineering Department
Dr. Faisal ShalabiEng. Hussein
AHMED HANI SALEM AL-OMARICivil Engineering431900
Ahmed Hani Salem Al-OmariID # 431900
Civil Engineering just4just.com/ahmed
Objective:
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- The objective of this experiment is to calculate the percentage of water in
some specific amount of soil in term of its dry mass.
- We do this experiment because we know then the moisture content and
from that we do our work or construction based on the water content because this
property is so important.
General Discussion:
- We can define the water content as the ratio of the mass of water present
to the total mass (water + soil).
- Experience indicates that this method of sample drying is sufficient for the
small samples (10 to 200 g) used in routine laboratory work. It is usual adequate
for much larger samples, 1000 g or more, but large samples be stirred
occasionally so uniform drying is obtained.
- It is usual to remove the water content samples from the oven and weigh
them immediately (we use heat-resistant gloves because they are hot).
- The oven temperature of 1100 C is too hot for certain organic soils, soils
containing appreciable amounts of gypsum or some other minerals, certain clays,
and some tropical soils.
.
Equipments:
- Moisture tin cups.
- Oven with accurate temperature control at 110 5 c.
- Balance, sensitive to 0.01g.
Procedures:
- We get a clean can and weight it as an empty one and get the reading.
- We put a representative sample of wet soil in the cup and determine the
mass of wet soil + can.
Note: if the mass is determined immediately, it is usually not necessary to place the
lid on the cup. But if there is a delay of 1 to 5 min or more, put the lid on the can so
soil does not dry and place the cup under a damp paper towel to maintain the
humidity in its vicinity.
Ahmed Hani Salem Al-OmariID # 431900
Civil Engineering just4just.com/ahmed
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- After weighing the wet sample + can, remove the lid- it is usual practice to place it
under the bottom of the can- and place the sample in the oven.
- After drying the sample to a constant mass and after two days we get the reading
of the weight of dry soil + can.
Calculations:
- Sample of calculations :
Wt. water (WW) = = gWt. dry soil (WS) = = g
Moisture content (percent) (W %) = ( / ) * 100 %= %
- Data sheets :
SOIL MOISTURE CONTENT DETERMINATION
Can Number 2A G2
1) Soil type sand clay
2) Wt. of can ( can weight) (g) 30 30.7
3) Wt. - wet soil + can - (g) 77.55 84.94
4) Wt. - dry soil + can - (g)
5) Wt. water - ( line 3 - line 4) WW (g)
6) Wt. - dry soil - ( line 4 -line 2) WS (g)
7) Moisture content (line 5 line 6) W(%)
Ahmed Hani Salem Al-OmariID # 431900Civil Engineering just4just.com/ahmed
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Discussion & Conclusions:
- Discuss results :
- From this test we see that the water content of Clay is bigger than the sandone :
Clay = %Sand = %
And that because the bond (or cohesive ) between the particle of twoof them and the size of these particle.
- The voids maybe occupied by either air or water or mixed the water molecules in thevoid make the water content and its different from soil to another. So its depend on type
of soil.
- Errors :
After drying the soil in oven, if the mass appears to be in error, first reweigh the can +
dry soil, and, if the new value appears satisfactory, continue. If it is not, next check if
you are using the same moisture and/or if they are in adjustment: also be sure the lid is
included if a metal moisture can is being used.
If these items all check and there is too much mass, you will have to discard this sample
because it is impossible for a "dry" sample to have a greater mass than a "wet" one (an
earlier weighing error has been made).
There may still be a weighing error, but at this point you have no means to identify it.
There is an error in the value of the soil weight, results from unadjusted balance, and
error in the period of time the sample was had in the oven to dry.
- Improvement :
When we heat some soils it might be changed in its characteristics. ASTM suggests anoven temperature of 600 C for drying these soils.
SAFETY: this test may be hazardous if the soil being dried contains certain chemicals.
For us as a student laboratories reliable soil sources should be used to avoid creating a
hazardous environment
Moisture content is one of the most important quantities in soil mechanics, because it's
easy to be evaluated in a lap, and the whole foundations of buildings depend on it.