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

Bulk density is the mass of aggregate required to fill a container of a specified unit volume and includes the volume of the particles and the voids between them.

Question 2

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

Accepted Answer

ASTM C29

Answer

ASTM C29 is the recognized method for measuring the bulk density and void content of aggregates.

Question 3

Why is determining void content in aggregates important?

Accepted Answer

To estimate cement requirements

Answer

Void content helps assess the space between aggregate particles, influencing concrete workability and mix proportions.

Question 4

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

Accepted Answer

Dark-colored solution compared to the standard

Answer

A darker color in the solution during the ASTM C40 test indicates the possible presence of organic impurities that can affect concrete strength.

Question 5

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

Accepted Answer

Reduced concrete strength

Answer

Excessive organic matter can interfere with cement hydration and significantly reduce the strength of hardened concrete.

(ATT) ACI Aggregate Testing Technician Practice Test

(ATT) ACI Aggregate Testing Technician Practice Test

ATT Bulk Density, Voids & Organic Impurities