NB ASBOG ASSORTED PG MATERIAL
QUESTIONS AND ANSWERS WITH
SOLUTIONS 2024
If more than 50% of soil is retained on the No. 200 sieve (0.003 inch), the soil is classified as: - ANSWER
Coarse grained
What sieve number is the boundary for coarse and fine grained soils? - ANSWER No. 200 (0.003 inch)
If more than 50% of soil is retained on the No 4 sieve, it is classified as a: - ANSWER Gravel
Material retained on this sieve number represents the smallest particle size visible to the unaided eye: -
ANSWER No. 200 (0.003 inch) sieve
The larger the "us standard sieve" number, the _____ the particle size. - ANSWER Smaller.
For example, gravel is retained on the no. 4 sieve, medium sand is retained on the no. 40 sieve, and find
grained sand is retained on the no. 200 sieve.
A soil is considered poorly graded if it contains ____ or fewer sieve sizes. - ANSWER 3
For a gravel or sand to be assigned a W or P, there must be what percentage or lower of fines? - ANSWER
<5% fines
A well-graded soil has a Uniformity coefficient of greater than ___ for gravel and ___ for sand - ANSWER
4, 6
If there are between 5% and 12% fines in a gravelly or sandy soil, what would the classification look like?
- ANSWER It would be a dual classification, showing the first group symbol plus a second that indicates
"with clay" or "with silt"
Eg:
GW-GM- well graded gravel with silt
SP-SC- poorly graded sand with clay
, Symbols used when fines exceed 12% of total sample weight - ANSWER "C" or "M"
Eg:
GM- silty gravel
SC- clayey sand
Uniformity coefficient equation - ANSWER Cu= D60/D10
Curvature coefficient equation - ANSWER Cc=D30^2/D10•D60
_____ have little to no strength when dry, while ____ have considerable strength. - ANSWER Silts, clays
The plasticity index value is determined using what lab method? - ANSWER Atterburg Limits test
Fine grained soils with a LL >50 are assigned what symbol? - ANSWER H (high plasticity)
Fine grained soils with LL<50 are assigned what symbol? - ANSWER L (low plasticity)
Fine grained soils with 30% or more coarse grained fractions should be modified with these descriptive
words: - ANSWER Gravelly or sandy
Dry strength _____ with increased plasticity - ANSWER Increases
Three field identification procedures for fine grained soils - ANSWER 1. Dry strength (crushing
characteristics)- silts and silty sands have a low dry strength, while clays have high strength
2. Dilatancy (reaction to shaking)- fine, clean sands exhibit water when shaken and disappearance of
water when squeezed, clays show no reaction.
3. Toughness (consistency near the plastic limit)- high plasticity clays form a tougher tread and stiffer
lump when it crumbles (reaches plastic limit)
QUESTIONS AND ANSWERS WITH
SOLUTIONS 2024
If more than 50% of soil is retained on the No. 200 sieve (0.003 inch), the soil is classified as: - ANSWER
Coarse grained
What sieve number is the boundary for coarse and fine grained soils? - ANSWER No. 200 (0.003 inch)
If more than 50% of soil is retained on the No 4 sieve, it is classified as a: - ANSWER Gravel
Material retained on this sieve number represents the smallest particle size visible to the unaided eye: -
ANSWER No. 200 (0.003 inch) sieve
The larger the "us standard sieve" number, the _____ the particle size. - ANSWER Smaller.
For example, gravel is retained on the no. 4 sieve, medium sand is retained on the no. 40 sieve, and find
grained sand is retained on the no. 200 sieve.
A soil is considered poorly graded if it contains ____ or fewer sieve sizes. - ANSWER 3
For a gravel or sand to be assigned a W or P, there must be what percentage or lower of fines? - ANSWER
<5% fines
A well-graded soil has a Uniformity coefficient of greater than ___ for gravel and ___ for sand - ANSWER
4, 6
If there are between 5% and 12% fines in a gravelly or sandy soil, what would the classification look like?
- ANSWER It would be a dual classification, showing the first group symbol plus a second that indicates
"with clay" or "with silt"
Eg:
GW-GM- well graded gravel with silt
SP-SC- poorly graded sand with clay
, Symbols used when fines exceed 12% of total sample weight - ANSWER "C" or "M"
Eg:
GM- silty gravel
SC- clayey sand
Uniformity coefficient equation - ANSWER Cu= D60/D10
Curvature coefficient equation - ANSWER Cc=D30^2/D10•D60
_____ have little to no strength when dry, while ____ have considerable strength. - ANSWER Silts, clays
The plasticity index value is determined using what lab method? - ANSWER Atterburg Limits test
Fine grained soils with a LL >50 are assigned what symbol? - ANSWER H (high plasticity)
Fine grained soils with LL<50 are assigned what symbol? - ANSWER L (low plasticity)
Fine grained soils with 30% or more coarse grained fractions should be modified with these descriptive
words: - ANSWER Gravelly or sandy
Dry strength _____ with increased plasticity - ANSWER Increases
Three field identification procedures for fine grained soils - ANSWER 1. Dry strength (crushing
characteristics)- silts and silty sands have a low dry strength, while clays have high strength
2. Dilatancy (reaction to shaking)- fine, clean sands exhibit water when shaken and disappearance of
water when squeezed, clays show no reaction.
3. Toughness (consistency near the plastic limit)- high plasticity clays form a tougher tread and stiffer
lump when it crumbles (reaches plastic limit)
