ACI ASTM C138 – Concrete Density, Yield and Air Content
Exam Questions with Correct Answers
Description: This file contains verified exam questions and answers for ACI’s ASTM C138,
which focuses on testing methods for density, yield, and air content of concrete. It includes
formulas, procedures, and interpretation of test results relevant to both lightweight and
heavyweight concretes. Designed for certification candidates, it ensures thorough
understanding of measurement accuracy, slump handling, and concrete consolidation
techniques.
ASTM C138 is used for what - answer✔✔test method for Density(unit weight), Yield, and
Air Content(gravimetric) of concrete A lower density may indicate what -
answer✔✔1)materials have changed[lower specific gravity], 2)higher water content,
3)higher air content, 4)a change in proportions of ingredients, and/or 5)lower cement
content. If a reduction of the density of the concrete was due to an increase in air content
what can be expected - answer✔✔the concrete could be more durable in resistance to
freezing and thawing, but the strength, abrasion resistance, resistance to chemical attack,
shrinkage, and cracking qualities of the concrete will be affected. density test must be used
on what type of concretes - answer✔✔lightweight and heavyweight A change in density
could affect the what - answer✔✔pumpability, placeability, finishability, and strength of
1
Page
all types of concrete. Yield is defined as what - answer✔✔the volume of concrete
Exam Questions with Correct Answers
Description: This file contains verified exam questions and answers for ACI’s ASTM C138,
which focuses on testing methods for density, yield, and air content of concrete. It includes
formulas, procedures, and interpretation of test results relevant to both lightweight and
heavyweight concretes. Designed for certification candidates, it ensures thorough
understanding of measurement accuracy, slump handling, and concrete consolidation
techniques.
ASTM C138 is used for what - answer✔✔test method for Density(unit weight), Yield, and
Air Content(gravimetric) of concrete A lower density may indicate what -
answer✔✔1)materials have changed[lower specific gravity], 2)higher water content,
3)higher air content, 4)a change in proportions of ingredients, and/or 5)lower cement
content. If a reduction of the density of the concrete was due to an increase in air content
what can be expected - answer✔✔the concrete could be more durable in resistance to
freezing and thawing, but the strength, abrasion resistance, resistance to chemical attack,
shrinkage, and cracking qualities of the concrete will be affected. density test must be used
on what type of concretes - answer✔✔lightweight and heavyweight A change in density
could affect the what - answer✔✔pumpability, placeability, finishability, and strength of
1
Page
all types of concrete. Yield is defined as what - answer✔✔the volume of concrete
