ATT Bulk Density, Voids & Organic Impurities

Question 1

What does bulk density of aggregate refer to?

Accepted Answer

Mass per unit volume including voids

Answer

Weight of aggregate particles only

Answer

Volume of water displaced by aggregate

Answer

Volume of air in concrete

Question 2

Which ASTM standard covers the determination of bulk density of aggregates?

Accepted Answer

ASTM C29

Answer

ASTM C40

Answer

ASTM C117

Answer

ASTM C128

Question 3

Why is determining void content in aggregates important?

Accepted Answer

To estimate cement requirements

Answer

To determine moisture content

Answer

To calculate absorption rate

Answer

To measure particle shape

Question 4

What is the visual indication of organic impurities in fine aggregates?

Accepted Answer

Dark-colored solution compared to the standard

Answer

Lighter solution than the standard

Answer

Yellowish tint in clear water

Answer

Frothy surface layer

Question 5

Which of the following can result from excessive organic impurities in aggregates?

Accepted Answer

Reduced concrete strength

Answer

Improved workability

Answer

Increased air content

Answer

Faster setting time

Question 6

What is the correct procedure when testing bulk density?

Accepted Answer

Fill using specified method such as rodding or shoveling

Answer

Fill the container randomly

Answer

Compact the sample with a rubber mallet

Answer

Use vacuum to settle particles