Question 1

What is the unit weight of a soil sample weighing 1.5 grams with a volume of 0.6 cubic centimeters (cm³)? A)0.9 g/cm³ B)2.5 g/cm³ C)7.5 g/cm³ D)Not enough information provided

Accepted Answer

The unit weight of a 0.6 cm³ soil sample weighing 1.5 grams is 2.5 g/cm³. Solution: Use the following equation to determine the solid unit weight, ?_s ?_s = mass of solids / volume of solids = 1.5 grams / 0.6 cm³ ?_s = 2.5

Question 2

Which of the following definitions best describes specific gravity (Gs) of a soil sample?&#10;A)The ratio of unit weight of a given soil to the unit weight of water&#10;B)Gravitational force caused by the soil mass within a unit volume of soil&#10;C)The ratio of the mass of a soil to the volume of the soil&#10;D)None of the above

Accepted Answer

The specific gravity of a soil is best described as the ratio of unit weight of a given soil to the unit weight of water. The unit weight is the product of density and gravity acceleration caused by the mass of material within a unit volume.

Question 3

What is the bulk density of a 1.5-liter dry soil sample with a mass of 4.2 kg? A)2.8 kg/m³ B)28 kg/m³ C)2,800 kg/m³ D)Not enough information provided

Accepted Answer

The bulk density of a 2-liter dry soil sample with a mass of 4.2 kg is 2,800 kg/m³. The bulk density is a measure of the mass of soil per unit volume. Solution: Use the following equation to determine bulk density, Db Db = Mass of dry soil / volume of solids and pore spaces = (4.2 kg) / [(1.5 liters) x (1 cubic meter (m³)/1,000 liters)] = 2,800 kg/m³

Question 4

Soil pores are classified into three main groups based on the diameter of individual pores. Which of the following pore diameter grouping is associated with mesopores?&#10;A)? 0.1 mm&#10;B)0.03 mm - 0.1 mm&#10;C)< 0.03 mm&#10;D)None of the above

Accepted Answer

The pore diameter grouping of 0.03 mm - 0.1 mm is associated with mesopores. A soil's ability to hold and transmit water and air is impacted by the amount of pore space in the soil (porosity) and its pore size distribution. Mesopores are medium-sized pores and are commonly found in medium-textured soils and loamy soils.

Question 5

What is the void ratio of a soil with a porosity of 40%?&#10;A)40%&#10;B)60%&#10;C)67%&#10;D)Not enough information provided

Accepted Answer

The void ratio of a given soil with a porosity of 40% is 67%. The void ratio is the relationship of voids to solids.
Solution: Use the following equation to determine Void ratio, e
e = volume of voids / volume of solids
= n / 1 - n
= 0.40 / (1-.40) x 100
e = 67%

Question 6

What is the void ratio of a 200 gram soil sample with an 80% degree of saturation and a moisture content of 20.5%? Assume the specific gravity of soil grains is 2.6.&#10;A)33%&#10;B)67%&#10;C)80%&#10;D)Not enough information provided

Accepted Answer

The void ratio of a 200 gram soil sample with an 80% degree of saturation and a moisture content of 20.5% is 67%.
Solution: Use the following equation to determine the void ratio, e
e = Specific gravity x moisture content / degree of saturation
= GS x W / S
Given specific gravity, GS = 2.6
moisture content, W = 20.5 %
degree of saturation, S = 80%
Therefore, e = [(2.6 x 20.5) / 80] x 100
e = 67%

Question 7

What is the dry unit weight of a 500 cubic meter (cm³) soil sample with a water weight of 100 grams (g) and a solids weight of 900 g? Assume the specific gravity of the sample is 2.65. A)1.8 g/cm³ B)1.6 g/cm³ C)9 g/cm³ D)Not enough information provided

Accepted Answer

The dry unit weight of a 500 cm³ soil sample with a water weight of 100 g and a solids weight of 900 g is 1.8 g/cm³. Solution: Use the following equation to determine the dry unit weight, ?_d ?_d = weight of solids / total volume = Ws / VT given Ws = 900 g VT = 500 cm³ Therefore, ?_d = 900 / 500 cm³ = 1.8 g/cm³

Question 8

What is the degree of saturation of a 600 cubic centimeter (cm³) soil sample given the following values from its three-phase diagram?
Volume of air: 100 cm³
Volume of solids: 320 cm³

A)30%
B)64.3%
C)87.5%
D)Not enough information provided

Accepted Answer

The degree of saturation of a 600 cm³ soil sample with the given volumetric values is 64.3%. Solution: Use the following equation to determine the degree of saturation, S S = (volume of water ) / (volume of voids) = V_w / V_v given V_v = (total volume) - (volume of solids) V_v = 600 - 320 = 280 cm³ and V_w = V_t - V_v - V_s V_w = 600 - 100 - 320 = 180 cm³ Therefore S V_w / V_v = (180 cm³ /280 cm³) x 100 = 64.3%

Question 9

What is the moisture content of a 1,000 gram (g) soil sample given the following value from its three-phase diagram?
Weight of solids: 890 g

A)11.0%
B)12.4%
C)89.0%
D)Not enough information provided

Accepted Answer

The moisture of a 1000 g soil sample with the given weight values is 12.4%. Solution: Use the following equation to determine the moisture content, w w = weight of water / weight of solids = W_w / W_s Given W_T = 1,000 g and W_s = 890 g, and the weight of air = 0 g, W_w = 110 g Therefore s = 110 g / 890 g x 100 = 12.4%

Question 10

Which of the following soil characteristics is an important consideration in highway pavement design?&#10;A)Uniformity&#10;B)Resilience&#10;C)Stability&#10;D)A. and C.

Accepted Answer

Uniformity and stability are important soil characteristic considerations in pavement design. The performance and durability of highway pavement is dependent on the underlying subgrade materials, and as such, the uniformity and stability of the soil beneath the highway is critical. In many cases, subgrade soil is brought to a highway construction site to replace unstable and non-uniform in situ soils discovered during the subgrade exploration phase of the project.

Deck 13: Soil and Materials