Answer :
To determine the AASHTO and USCS classifications for the given soil based on the sieve analysis and atterberg limits (Liquid Limit and Plastic Limit), let's go through the process step by step:
### Step 1: Understand the Data
- Sieve Analysis: We have the percentage of the soil mass retained on different sieves.
- Atterberg Limits: We are given the Liquid Limit (LL) as 26 and the Plastic Limit (PL) as 18.
- Plasticity Index (PI): Calculated as PI = LL - PL = 26 - 18 = 8.
### Step 2: Sieve Analysis Results
After calculating the cumulative mass and percentage passing for the sieves, here's what we find:
- Percent passing finer than the #200 sieve (0.075 mm size) is 36.8%.
### Step 3: AASHTO Classification
For AASHTO classification:
- Since more than 35% of the particles pass through the #200 sieve and the Plasticity Index (PI) is 8, we must determine if it fits into the "A-2-4" category.
- However, the given condition for the A-2-4 category would typically apply if PI < 6. Therefore, with PI = 8, we see the soil does not fit into the A-2-4 category.
So, the AASHTO classification is "Not in A-2-4 category."
### Step 4: USCS Classification
For USCS classification:
- Since LL is less than 50 and the Plasticity Index (PI) is 8, we need to check specific criteria:
- If PI ≥ 7, the soil can often be classified as low plastic clay (CL).
- If PI < 7 and it's near the borderline, it might be classified as silty clay or another type depending on the context, but here with PI = 8, we consider it as "CL".
Therefore, the USCS classification is "CL."
In conclusion, based on the given data, the classifications are:
- AASHTO Classification: Not in A-2-4 category
- USCS Classification: CL
### Step 1: Understand the Data
- Sieve Analysis: We have the percentage of the soil mass retained on different sieves.
- Atterberg Limits: We are given the Liquid Limit (LL) as 26 and the Plastic Limit (PL) as 18.
- Plasticity Index (PI): Calculated as PI = LL - PL = 26 - 18 = 8.
### Step 2: Sieve Analysis Results
After calculating the cumulative mass and percentage passing for the sieves, here's what we find:
- Percent passing finer than the #200 sieve (0.075 mm size) is 36.8%.
### Step 3: AASHTO Classification
For AASHTO classification:
- Since more than 35% of the particles pass through the #200 sieve and the Plasticity Index (PI) is 8, we must determine if it fits into the "A-2-4" category.
- However, the given condition for the A-2-4 category would typically apply if PI < 6. Therefore, with PI = 8, we see the soil does not fit into the A-2-4 category.
So, the AASHTO classification is "Not in A-2-4 category."
### Step 4: USCS Classification
For USCS classification:
- Since LL is less than 50 and the Plasticity Index (PI) is 8, we need to check specific criteria:
- If PI ≥ 7, the soil can often be classified as low plastic clay (CL).
- If PI < 7 and it's near the borderline, it might be classified as silty clay or another type depending on the context, but here with PI = 8, we consider it as "CL".
Therefore, the USCS classification is "CL."
In conclusion, based on the given data, the classifications are:
- AASHTO Classification: Not in A-2-4 category
- USCS Classification: CL