ATT Moisture Content & Specific Gravity 1 — Questions and Answers
Question 1: Which ASTM standard is used to determine the moisture content of aggregates?
- ASTM C127
- ASTM C128
- ASTM C566 (Correct answer)
- ASTM C29
Correct answer: ASTM C566
ASTM C566 provides the standard test method for total moisture content of aggregates by drying.
Question 2: What condition must fine aggregate be in to determine surface moisture?
- Air dry
- Wet
- Saturated surface-dry (Correct answer)
- Oven dry
Correct answer: Saturated surface-dry
The saturated surface-dry (SSD) condition eliminates the influence of surface moisture for accurate calculations.
Question 3: What is the purpose of determining specific gravity of aggregates?
- To find aggregate color
- To estimate compressive strength
- To measure density and absorption (Correct answer)
- To check gradation
Correct answer: To measure density and absorption
Specific gravity helps in concrete mix design and quality control by measuring the density of the aggregate.
Question 4: Which test method determines the specific gravity of coarse aggregates?
- ASTM C29
- ASTM C117
- ASTM C127 (Correct answer)
- ASTM C136
Correct answer: ASTM C127
ASTM C127 outlines the procedure for determining specific gravity and absorption of coarse aggregates.
Question 5: What is the correct sequence of aggregate moisture conditions from driest to wettest?
- Wet, SSD, air dry, oven dry
- Air dry, wet, oven dry, SSD
- Oven dry, air dry, SSD, wet (Correct answer)
- SSD, oven dry, air dry, wet
Correct answer: Oven dry, air dry, SSD, wet
Oven dry, air dry, SSD, and then wet describe the increasing order of moisture content in aggregates.
Question 6: Why is SSD condition critical in concrete mix design?
- To prevent evaporation of water
- To control concrete temperature
- To ensure proper cement hydration
- To account for water absorption accurately (Correct answer)
Correct answer: To account for water absorption accurately
Using aggregates in SSD condition ensures that water added during mixing is not absorbed or added by the aggregate.
ATT Moisture Content & Specific Gravity 1
Which ASTM standard is used to determine the moisture content of aggregates?