State whether the following are true or false. a. In the AASHTO classification Table 4.1, the soils that are more suitable for roadwork are located on the left than right. b. In AASHTO classification system, the better performing fine grained soils are the ones with lower group indices. c. In AASHTO classification system, sands are classified as grains with 0.075-4.75 mm diameter. d. The USCS symbol for clayey gravel is CG. e. A soil with USCS symbol SM is sandy silt.

Question

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Answer 1

Textbook Question

Chapter 4, Problem 4.1P

State whether the following are true or false.

a. In the AASHTO classification Table 4.1, the soils that are more suitable for roadwork are located on the left than right.

b. In AASHTO classification system, the better performing fine grained soils are the ones with lower group indices.

c. In AASHTO classification system, sands are classified as grains with 0.075-4.75 mm diameter.

d. The USCS symbol for clayey gravel is CG.

e. A soil with USCS symbol SM is sandy silt.

(a)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “In the AASHTO classification Table 4.1, the soils that are more suitable for roadwork are located on left than right” is true.

Explanation of Solution

Refer Table 4.1, “Classification of highway Subgrade Materials” in the textbook.

Consider the Granular materials are listed left side in the table and Silt-clay materials are listed right side in the Table.
The soil groups are classified by AASHTO system as A-1, A-2, A-3, A-4, A-5, A-6 and A-7.
The group classification of the soil A-1 and A-2 belongs to left side of the table and A-4 to A-7 belongs to right side of the table.
The general subgrade rating of the soil A-1 and A-2 has ‘excellent to good’.
The general subgrade rating of the soil A-4 to A-7 has ‘fair to poor’.

Generally the rating from excellent to good subgrade materials are suitable for roadwork. So the classification of the soil A-1 and A-2 is used for roadwork, but the soil group A-4 to A-7 is not used for road work due to its poor rating.

Thus, the soils belongs to left side than the right side of the table is fit for roadwork.

Therefore, the statement, “In the AASHTO classification Table 4.1, the soils that are more suitable for roadwork are located on left than right” is true.

(b)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “In the AASHTO classification system, the better performing fine grained soils are the ones with lower group indices” is true.

Explanation of Solution

Refer Table 4.1, “Classification of highway Subgrade Materials” in the textbook.

The AASHTO system classified the soil group as A-1, A-2, A-3, A-4, A-5, A-6 and A-7.
The group classification of the soil A-1 and A-2 belongs to granular materials and the soil A-4 to A-7 belongs to Silt-clay materials
From the sieve analysis the gravel, sand and fine sand are grouping under soil A1 and A2 and silty soils and clayey soils are grouping under A-4, A-5, A-6 and A-7.
The soil group A-1 and A-2 is rated as ‘excellent to good’.so it is considered as better performing fine grained soils.

Thus, the better performing fine grained soils are the ones with lower group indices (A-1 and A-2).

Therefore, The statement, “In the AASHTO classification system, the better performing fine grained soils are the ones with lower group indices” is true.

(c)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “In the AASHTO classification system, sands are classified as grains with 0.075-4.75 mm diameter” is false.

Explanation of Solution

As per AASHTO system, the grain size from 2 mm to 0.075 mm is classified as sand.

As per USCS system, the grain size from 4.75 to 0.075 mm is classified as sand.

The sand is classified by USCS system, but in the given statement mentioned as AASHTO system. So the statement is wrong.

Therefore, The statement, “In the AASHTO classification system, sands are classified as grains with 0.075-4.75 mm diameter” is false.

(d)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “The USCS symbol for clayey gravel is CG” is false.

Explanation of Solution

Refer to Figure 4.3, “Flowchart group names for gravelly and sandy soil”

The group symbol ‘GC’ represents the group name as ‘clayey gravel’ and ‘clayey gravel with sand’.

As per USCS system, the correct group symbol for clayey soil is GC. Hence the given statement is wrong.

Therefore, The statement, “The USCS symbol for clayey gravel is CG” is false.

(e)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “A soil with USCS symbol SM is sandy silt” is false.

Explanation of Solution

Refer to Figure 4.3, “Flowchart group names for gravelly and sandy soil”

The group symbol ‘SM’ is represents the group name as ‘silty sand’ and ‘silty sand with gravel’.

As per USCS system, the correct group name for the symbol SM is silty sand and silty sand with gravel, but in the given statement it is mentioned as sandy silt. Hence, the given statement is wrong.

Therefore, the statement, “A soil with USCS symbol SM is sandy silt” is false.

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Students have asked these similar questions

A fine-grained soil (no sand) is found to have a liquid limit of 70 percent and a plastic limit of 38 percent. (a) What do the percentages for these limit values represent? (b) What is the plasticity index for this soil? (c) On the plasticity chart for the Unified Soil Classification System, what soil type is this? (d) On the plasticity chart for the AASHTO classification system, what soil type is this?

Answer the following: a) What is the difference between the U-line and the A-line on a plasticity chart? b) What is the dividing point between silts and clays on a plasticity chart? c) What is the dividing point between low, medium, and high plasticity on a plasticity chart? d) An inorganic soil has a Liquid Limit of 55 and a Plastic Limit of 30. Using the plasticity chart determine the relative classification for this soil.

find the following: a. What is the value of the percent passing for sieve with 2 mm. opening in percentage? b. What is the value of the percent passing for sieve with 150 μm. opening in percentage? c. What is the value of the Effective Size of soil in mm.? d. What is the value of the coefficient of gradation?e.What is the value of the coefficient of uniformity? f. What are the percentages of gravel, sand, and Fines using the limits indicated by USCS? g. What are the percentages of gravel, sand, silt and clay using the limits indicated by MIT? h. What are the percentages of gravel, sand, silt and clay using the limits indicated by AASHTO? i. What are the percentages of gravel, sand, silt and clay using the limits indicated by USDA?

Answer 2

Textbook Question

Chapter 4, Problem 4.1P

State whether the following are true or false.

a. In the AASHTO classification Table 4.1, the soils that are more suitable for roadwork are located on the left than right.

b. In AASHTO classification system, the better performing fine grained soils are the ones with lower group indices.

c. In AASHTO classification system, sands are classified as grains with 0.075-4.75 mm diameter.

d. The USCS symbol for clayey gravel is CG.

e. A soil with USCS symbol SM is sandy silt.

(a)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “In the AASHTO classification Table 4.1, the soils that are more suitable for roadwork are located on left than right” is true.

Explanation of Solution

Refer Table 4.1, “Classification of highway Subgrade Materials” in the textbook.

Consider the Granular materials are listed left side in the table and Silt-clay materials are listed right side in the Table.
The soil groups are classified by AASHTO system as A-1, A-2, A-3, A-4, A-5, A-6 and A-7.
The group classification of the soil A-1 and A-2 belongs to left side of the table and A-4 to A-7 belongs to right side of the table.
The general subgrade rating of the soil A-1 and A-2 has ‘excellent to good’.
The general subgrade rating of the soil A-4 to A-7 has ‘fair to poor’.

Generally the rating from excellent to good subgrade materials are suitable for roadwork. So the classification of the soil A-1 and A-2 is used for roadwork, but the soil group A-4 to A-7 is not used for road work due to its poor rating.

Thus, the soils belongs to left side than the right side of the table is fit for roadwork.

Therefore, the statement, “In the AASHTO classification Table 4.1, the soils that are more suitable for roadwork are located on left than right” is true.

(b)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “In the AASHTO classification system, the better performing fine grained soils are the ones with lower group indices” is true.

Explanation of Solution

Refer Table 4.1, “Classification of highway Subgrade Materials” in the textbook.

The AASHTO system classified the soil group as A-1, A-2, A-3, A-4, A-5, A-6 and A-7.
The group classification of the soil A-1 and A-2 belongs to granular materials and the soil A-4 to A-7 belongs to Silt-clay materials
From the sieve analysis the gravel, sand and fine sand are grouping under soil A1 and A2 and silty soils and clayey soils are grouping under A-4, A-5, A-6 and A-7.
The soil group A-1 and A-2 is rated as ‘excellent to good’.so it is considered as better performing fine grained soils.

Thus, the better performing fine grained soils are the ones with lower group indices (A-1 and A-2).

Therefore, The statement, “In the AASHTO classification system, the better performing fine grained soils are the ones with lower group indices” is true.

(c)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “In the AASHTO classification system, sands are classified as grains with 0.075-4.75 mm diameter” is false.

Explanation of Solution

As per AASHTO system, the grain size from 2 mm to 0.075 mm is classified as sand.

As per USCS system, the grain size from 4.75 to 0.075 mm is classified as sand.

The sand is classified by USCS system, but in the given statement mentioned as AASHTO system. So the statement is wrong.

Therefore, The statement, “In the AASHTO classification system, sands are classified as grains with 0.075-4.75 mm diameter” is false.

(d)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “The USCS symbol for clayey gravel is CG” is false.

Explanation of Solution

Refer to Figure 4.3, “Flowchart group names for gravelly and sandy soil”

The group symbol ‘GC’ represents the group name as ‘clayey gravel’ and ‘clayey gravel with sand’.

As per USCS system, the correct group symbol for clayey soil is GC. Hence the given statement is wrong.

Therefore, The statement, “The USCS symbol for clayey gravel is CG” is false.

(e)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “A soil with USCS symbol SM is sandy silt” is false.

Explanation of Solution

Refer to Figure 4.3, “Flowchart group names for gravelly and sandy soil”

The group symbol ‘SM’ is represents the group name as ‘silty sand’ and ‘silty sand with gravel’.

As per USCS system, the correct group name for the symbol SM is silty sand and silty sand with gravel, but in the given statement it is mentioned as sandy silt. Hence, the given statement is wrong.

Therefore, the statement, “A soil with USCS symbol SM is sandy silt” is false.

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Answer 3

Textbook Question

Chapter 4, Problem 4.1P

State whether the following are true or false.

a. In the AASHTO classification Table 4.1, the soils that are more suitable for roadwork are located on the left than right.

b. In AASHTO classification system, the better performing fine grained soils are the ones with lower group indices.

c. In AASHTO classification system, sands are classified as grains with 0.075-4.75 mm diameter.

d. The USCS symbol for clayey gravel is CG.

e. A soil with USCS symbol SM is sandy silt.

(a)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “In the AASHTO classification Table 4.1, the soils that are more suitable for roadwork are located on left than right” is true.

Explanation of Solution

Refer Table 4.1, “Classification of highway Subgrade Materials” in the textbook.

Consider the Granular materials are listed left side in the table and Silt-clay materials are listed right side in the Table.
The soil groups are classified by AASHTO system as A-1, A-2, A-3, A-4, A-5, A-6 and A-7.
The group classification of the soil A-1 and A-2 belongs to left side of the table and A-4 to A-7 belongs to right side of the table.
The general subgrade rating of the soil A-1 and A-2 has ‘excellent to good’.
The general subgrade rating of the soil A-4 to A-7 has ‘fair to poor’.

Generally the rating from excellent to good subgrade materials are suitable for roadwork. So the classification of the soil A-1 and A-2 is used for roadwork, but the soil group A-4 to A-7 is not used for road work due to its poor rating.

Thus, the soils belongs to left side than the right side of the table is fit for roadwork.

Therefore, the statement, “In the AASHTO classification Table 4.1, the soils that are more suitable for roadwork are located on left than right” is true.

(b)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “In the AASHTO classification system, the better performing fine grained soils are the ones with lower group indices” is true.

Explanation of Solution

Refer Table 4.1, “Classification of highway Subgrade Materials” in the textbook.

The AASHTO system classified the soil group as A-1, A-2, A-3, A-4, A-5, A-6 and A-7.
The group classification of the soil A-1 and A-2 belongs to granular materials and the soil A-4 to A-7 belongs to Silt-clay materials
From the sieve analysis the gravel, sand and fine sand are grouping under soil A1 and A2 and silty soils and clayey soils are grouping under A-4, A-5, A-6 and A-7.
The soil group A-1 and A-2 is rated as ‘excellent to good’.so it is considered as better performing fine grained soils.

Thus, the better performing fine grained soils are the ones with lower group indices (A-1 and A-2).

Therefore, The statement, “In the AASHTO classification system, the better performing fine grained soils are the ones with lower group indices” is true.

(c)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “In the AASHTO classification system, sands are classified as grains with 0.075-4.75 mm diameter” is false.

Explanation of Solution

As per AASHTO system, the grain size from 2 mm to 0.075 mm is classified as sand.

As per USCS system, the grain size from 4.75 to 0.075 mm is classified as sand.

The sand is classified by USCS system, but in the given statement mentioned as AASHTO system. So the statement is wrong.

Therefore, The statement, “In the AASHTO classification system, sands are classified as grains with 0.075-4.75 mm diameter” is false.

(d)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “The USCS symbol for clayey gravel is CG” is false.

Explanation of Solution

Refer to Figure 4.3, “Flowchart group names for gravelly and sandy soil”

The group symbol ‘GC’ represents the group name as ‘clayey gravel’ and ‘clayey gravel with sand’.

As per USCS system, the correct group symbol for clayey soil is GC. Hence the given statement is wrong.

Therefore, The statement, “The USCS symbol for clayey gravel is CG” is false.

(e)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “A soil with USCS symbol SM is sandy silt” is false.

Explanation of Solution

Refer to Figure 4.3, “Flowchart group names for gravelly and sandy soil”

The group symbol ‘SM’ is represents the group name as ‘silty sand’ and ‘silty sand with gravel’.

As per USCS system, the correct group name for the symbol SM is silty sand and silty sand with gravel, but in the given statement it is mentioned as sandy silt. Hence, the given statement is wrong.

Therefore, the statement, “A soil with USCS symbol SM is sandy silt” is false.

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Answer 4

Textbook Question

Chapter 4, Problem 4.1P

State whether the following are true or false.

a. In the AASHTO classification Table 4.1, the soils that are more suitable for roadwork are located on the left than right.

b. In AASHTO classification system, the better performing fine grained soils are the ones with lower group indices.

c. In AASHTO classification system, sands are classified as grains with 0.075-4.75 mm diameter.

d. The USCS symbol for clayey gravel is CG.

e. A soil with USCS symbol SM is sandy silt.

(a)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “In the AASHTO classification Table 4.1, the soils that are more suitable for roadwork are located on left than right” is true.

Explanation of Solution

Refer Table 4.1, “Classification of highway Subgrade Materials” in the textbook.

Consider the Granular materials are listed left side in the table and Silt-clay materials are listed right side in the Table.
The soil groups are classified by AASHTO system as A-1, A-2, A-3, A-4, A-5, A-6 and A-7.
The group classification of the soil A-1 and A-2 belongs to left side of the table and A-4 to A-7 belongs to right side of the table.
The general subgrade rating of the soil A-1 and A-2 has ‘excellent to good’.
The general subgrade rating of the soil A-4 to A-7 has ‘fair to poor’.

Generally the rating from excellent to good subgrade materials are suitable for roadwork. So the classification of the soil A-1 and A-2 is used for roadwork, but the soil group A-4 to A-7 is not used for road work due to its poor rating.

Thus, the soils belongs to left side than the right side of the table is fit for roadwork.

Therefore, the statement, “In the AASHTO classification Table 4.1, the soils that are more suitable for roadwork are located on left than right” is true.

(b)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “In the AASHTO classification system, the better performing fine grained soils are the ones with lower group indices” is true.

Explanation of Solution

Refer Table 4.1, “Classification of highway Subgrade Materials” in the textbook.

The AASHTO system classified the soil group as A-1, A-2, A-3, A-4, A-5, A-6 and A-7.
The group classification of the soil A-1 and A-2 belongs to granular materials and the soil A-4 to A-7 belongs to Silt-clay materials
From the sieve analysis the gravel, sand and fine sand are grouping under soil A1 and A2 and silty soils and clayey soils are grouping under A-4, A-5, A-6 and A-7.
The soil group A-1 and A-2 is rated as ‘excellent to good’.so it is considered as better performing fine grained soils.

Thus, the better performing fine grained soils are the ones with lower group indices (A-1 and A-2).

Therefore, The statement, “In the AASHTO classification system, the better performing fine grained soils are the ones with lower group indices” is true.

(c)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “In the AASHTO classification system, sands are classified as grains with 0.075-4.75 mm diameter” is false.

Explanation of Solution

As per AASHTO system, the grain size from 2 mm to 0.075 mm is classified as sand.

As per USCS system, the grain size from 4.75 to 0.075 mm is classified as sand.

The sand is classified by USCS system, but in the given statement mentioned as AASHTO system. So the statement is wrong.

Therefore, The statement, “In the AASHTO classification system, sands are classified as grains with 0.075-4.75 mm diameter” is false.

(d)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “The USCS symbol for clayey gravel is CG” is false.

Explanation of Solution

Refer to Figure 4.3, “Flowchart group names for gravelly and sandy soil”

The group symbol ‘GC’ represents the group name as ‘clayey gravel’ and ‘clayey gravel with sand’.

As per USCS system, the correct group symbol for clayey soil is GC. Hence the given statement is wrong.

Therefore, The statement, “The USCS symbol for clayey gravel is CG” is false.

(e)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “A soil with USCS symbol SM is sandy silt” is false.

Explanation of Solution

Refer to Figure 4.3, “Flowchart group names for gravelly and sandy soil”

The group symbol ‘SM’ is represents the group name as ‘silty sand’ and ‘silty sand with gravel’.

As per USCS system, the correct group name for the symbol SM is silty sand and silty sand with gravel, but in the given statement it is mentioned as sandy silt. Hence, the given statement is wrong.

Therefore, the statement, “A soil with USCS symbol SM is sandy silt” is false.

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Answer 5

Textbook Question

Answer 6

Textbook Question

Answer 7

(a)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “In the AASHTO classification Table 4.1, the soils that are more suitable for roadwork are located on left than right” is true.

Explanation of Solution

Refer Table 4.1, “Classification of highway Subgrade Materials” in the textbook.

Consider the Granular materials are listed left side in the table and Silt-clay materials are listed right side in the Table.
The soil groups are classified by AASHTO system as A-1, A-2, A-3, A-4, A-5, A-6 and A-7.
The group classification of the soil A-1 and A-2 belongs to left side of the table and A-4 to A-7 belongs to right side of the table.
The general subgrade rating of the soil A-1 and A-2 has ‘excellent to good’.
The general subgrade rating of the soil A-4 to A-7 has ‘fair to poor’.

Generally the rating from excellent to good subgrade materials are suitable for roadwork. So the classification of the soil A-1 and A-2 is used for roadwork, but the soil group A-4 to A-7 is not used for road work due to its poor rating.

Thus, the soils belongs to left side than the right side of the table is fit for roadwork.

Therefore, the statement, “In the AASHTO classification Table 4.1, the soils that are more suitable for roadwork are located on left than right” is true.

(b)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “In the AASHTO classification system, the better performing fine grained soils are the ones with lower group indices” is true.

Explanation of Solution

Refer Table 4.1, “Classification of highway Subgrade Materials” in the textbook.

The AASHTO system classified the soil group as A-1, A-2, A-3, A-4, A-5, A-6 and A-7.
The group classification of the soil A-1 and A-2 belongs to granular materials and the soil A-4 to A-7 belongs to Silt-clay materials
From the sieve analysis the gravel, sand and fine sand are grouping under soil A1 and A2 and silty soils and clayey soils are grouping under A-4, A-5, A-6 and A-7.
The soil group A-1 and A-2 is rated as ‘excellent to good’.so it is considered as better performing fine grained soils.

Thus, the better performing fine grained soils are the ones with lower group indices (A-1 and A-2).

Therefore, The statement, “In the AASHTO classification system, the better performing fine grained soils are the ones with lower group indices” is true.

(c)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “In the AASHTO classification system, sands are classified as grains with 0.075-4.75 mm diameter” is false.

Explanation of Solution

As per AASHTO system, the grain size from 2 mm to 0.075 mm is classified as sand.

As per USCS system, the grain size from 4.75 to 0.075 mm is classified as sand.

The sand is classified by USCS system, but in the given statement mentioned as AASHTO system. So the statement is wrong.

Therefore, The statement, “In the AASHTO classification system, sands are classified as grains with 0.075-4.75 mm diameter” is false.

(d)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “The USCS symbol for clayey gravel is CG” is false.

Explanation of Solution

Refer to Figure 4.3, “Flowchart group names for gravelly and sandy soil”

The group symbol ‘GC’ represents the group name as ‘clayey gravel’ and ‘clayey gravel with sand’.

As per USCS system, the correct group symbol for clayey soil is GC. Hence the given statement is wrong.

Therefore, The statement, “The USCS symbol for clayey gravel is CG” is false.

(e)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “A soil with USCS symbol SM is sandy silt” is false.

Explanation of Solution

Refer to Figure 4.3, “Flowchart group names for gravelly and sandy soil”

The group symbol ‘SM’ is represents the group name as ‘silty sand’ and ‘silty sand with gravel’.

As per USCS system, the correct group name for the symbol SM is silty sand and silty sand with gravel, but in the given statement it is mentioned as sandy silt. Hence, the given statement is wrong.

Therefore, the statement, “A soil with USCS symbol SM is sandy silt” is false.

Answer 8

(a)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “In the AASHTO classification Table 4.1, the soils that are more suitable for roadwork are located on left than right” is true.

Explanation of Solution

Refer Table 4.1, “Classification of highway Subgrade Materials” in the textbook.

Consider the Granular materials are listed left side in the table and Silt-clay materials are listed right side in the Table.
The soil groups are classified by AASHTO system as A-1, A-2, A-3, A-4, A-5, A-6 and A-7.
The group classification of the soil A-1 and A-2 belongs to left side of the table and A-4 to A-7 belongs to right side of the table.
The general subgrade rating of the soil A-1 and A-2 has ‘excellent to good’.
The general subgrade rating of the soil A-4 to A-7 has ‘fair to poor’.

Generally the rating from excellent to good subgrade materials are suitable for roadwork. So the classification of the soil A-1 and A-2 is used for roadwork, but the soil group A-4 to A-7 is not used for road work due to its poor rating.

Thus, the soils belongs to left side than the right side of the table is fit for roadwork.

Therefore, the statement, “In the AASHTO classification Table 4.1, the soils that are more suitable for roadwork are located on left than right” is true.

Answer 9

(a)

Expert Solution

Answer 10

(a)

Expert Solution

Answer 11

Expert Solution

Answer 12

To determine

Find whether the statement is true or false.

Answer 13

Answer to Problem 4.1P

The statement, “In the AASHTO classification Table 4.1, the soils that are more suitable for roadwork are located on left than right” is true.

Answer 14

Explanation of Solution

Refer Table 4.1, “Classification of highway Subgrade Materials” in the textbook.

Consider the Granular materials are listed left side in the table and Silt-clay materials are listed right side in the Table.
The soil groups are classified by AASHTO system as A-1, A-2, A-3, A-4, A-5, A-6 and A-7.
The group classification of the soil A-1 and A-2 belongs to left side of the table and A-4 to A-7 belongs to right side of the table.
The general subgrade rating of the soil A-1 and A-2 has ‘excellent to good’.
The general subgrade rating of the soil A-4 to A-7 has ‘fair to poor’.

Generally the rating from excellent to good subgrade materials are suitable for roadwork. So the classification of the soil A-1 and A-2 is used for roadwork, but the soil group A-4 to A-7 is not used for road work due to its poor rating.

Thus, the soils belongs to left side than the right side of the table is fit for roadwork.

Therefore, the statement, “In the AASHTO classification Table 4.1, the soils that are more suitable for roadwork are located on left than right” is true.

Answer 15

(b)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “In the AASHTO classification system, the better performing fine grained soils are the ones with lower group indices” is true.

Explanation of Solution

Refer Table 4.1, “Classification of highway Subgrade Materials” in the textbook.

The AASHTO system classified the soil group as A-1, A-2, A-3, A-4, A-5, A-6 and A-7.
The group classification of the soil A-1 and A-2 belongs to granular materials and the soil A-4 to A-7 belongs to Silt-clay materials
From the sieve analysis the gravel, sand and fine sand are grouping under soil A1 and A2 and silty soils and clayey soils are grouping under A-4, A-5, A-6 and A-7.
The soil group A-1 and A-2 is rated as ‘excellent to good’.so it is considered as better performing fine grained soils.

Thus, the better performing fine grained soils are the ones with lower group indices (A-1 and A-2).

Therefore, The statement, “In the AASHTO classification system, the better performing fine grained soils are the ones with lower group indices” is true.

Answer 16

(b)

Expert Solution

Answer 17

(b)

Expert Solution

Answer 18

Expert Solution

Answer 19

To determine

Find whether the statement is true or false.

Answer 20

Answer to Problem 4.1P

The statement, “In the AASHTO classification system, the better performing fine grained soils are the ones with lower group indices” is true.

Answer 21

Explanation of Solution

Refer Table 4.1, “Classification of highway Subgrade Materials” in the textbook.

The AASHTO system classified the soil group as A-1, A-2, A-3, A-4, A-5, A-6 and A-7.
The group classification of the soil A-1 and A-2 belongs to granular materials and the soil A-4 to A-7 belongs to Silt-clay materials
From the sieve analysis the gravel, sand and fine sand are grouping under soil A1 and A2 and silty soils and clayey soils are grouping under A-4, A-5, A-6 and A-7.
The soil group A-1 and A-2 is rated as ‘excellent to good’.so it is considered as better performing fine grained soils.

Thus, the better performing fine grained soils are the ones with lower group indices (A-1 and A-2).

Therefore, The statement, “In the AASHTO classification system, the better performing fine grained soils are the ones with lower group indices” is true.

Answer 22

(c)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “In the AASHTO classification system, sands are classified as grains with 0.075-4.75 mm diameter” is false.

Explanation of Solution

As per AASHTO system, the grain size from 2 mm to 0.075 mm is classified as sand.

As per USCS system, the grain size from 4.75 to 0.075 mm is classified as sand.

The sand is classified by USCS system, but in the given statement mentioned as AASHTO system. So the statement is wrong.

Therefore, The statement, “In the AASHTO classification system, sands are classified as grains with 0.075-4.75 mm diameter” is false.

Answer 23

(c)

Expert Solution

Answer 24

(c)

Expert Solution

Answer 25

Expert Solution

Answer 26

To determine

Find whether the statement is true or false.

Answer 27

Answer to Problem 4.1P

The statement, “In the AASHTO classification system, sands are classified as grains with 0.075-4.75 mm diameter” is false.

Answer 28

Explanation of Solution

As per AASHTO system, the grain size from 2 mm to 0.075 mm is classified as sand.

As per USCS system, the grain size from 4.75 to 0.075 mm is classified as sand.

The sand is classified by USCS system, but in the given statement mentioned as AASHTO system. So the statement is wrong.

Therefore, The statement, “In the AASHTO classification system, sands are classified as grains with 0.075-4.75 mm diameter” is false.

Answer 29

(d)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “The USCS symbol for clayey gravel is CG” is false.

Explanation of Solution

Refer to Figure 4.3, “Flowchart group names for gravelly and sandy soil”

The group symbol ‘GC’ represents the group name as ‘clayey gravel’ and ‘clayey gravel with sand’.

As per USCS system, the correct group symbol for clayey soil is GC. Hence the given statement is wrong.

Therefore, The statement, “The USCS symbol for clayey gravel is CG” is false.

Answer 30

(d)

Expert Solution

Answer 31

(d)

Expert Solution

Answer 32

Expert Solution

Answer 33

To determine

Find whether the statement is true or false.

Answer 34

Answer to Problem 4.1P

The statement, “The USCS symbol for clayey gravel is CG” is false.

Answer 35

Explanation of Solution

Refer to Figure 4.3, “Flowchart group names for gravelly and sandy soil”

The group symbol ‘GC’ represents the group name as ‘clayey gravel’ and ‘clayey gravel with sand’.

As per USCS system, the correct group symbol for clayey soil is GC. Hence the given statement is wrong.

Therefore, The statement, “The USCS symbol for clayey gravel is CG” is false.

Answer 36

(e)

Expert Solution

To determine

Find whether the statement is true or false.

Answer to Problem 4.1P

The statement, “A soil with USCS symbol SM is sandy silt” is false.

Explanation of Solution

Refer to Figure 4.3, “Flowchart group names for gravelly and sandy soil”

The group symbol ‘SM’ is represents the group name as ‘silty sand’ and ‘silty sand with gravel’.

As per USCS system, the correct group name for the symbol SM is silty sand and silty sand with gravel, but in the given statement it is mentioned as sandy silt. Hence, the given statement is wrong.

Therefore, the statement, “A soil with USCS symbol SM is sandy silt” is false.

Answer 37

(e)

Expert Solution

Answer 38

(e)

Expert Solution

Answer 39

Expert Solution

Answer 40

To determine

Find whether the statement is true or false.

Answer 41

Answer to Problem 4.1P

The statement, “A soil with USCS symbol SM is sandy silt” is false.

Answer 42

Explanation of Solution

Refer to Figure 4.3, “Flowchart group names for gravelly and sandy soil”

The group symbol ‘SM’ is represents the group name as ‘silty sand’ and ‘silty sand with gravel’.

As per USCS system, the correct group name for the symbol SM is silty sand and silty sand with gravel, but in the given statement it is mentioned as sandy silt. Hence, the given statement is wrong.

Therefore, the statement, “A soil with USCS symbol SM is sandy silt” is false.