Building Engineering Construction Materials and Properties 2

Question 1

The slump test performed on fresh concrete primarily measures which property?

Accepted Answer

Workability and consistency

Answer

28-day compressive strength

Answer

Air content percentage

Answer

Aggregate gradation

Question 2

Per ASTM C39, what is the standard age at which concrete cylinder specimens are tested for compressive strength?

Accepted Answer

28 days

Answer

7 days

Answer

14 days

Answer

56 days

Question 3

The modulus of elasticity (Young's modulus) of structural steel is approximately:

Accepted Answer

29,000 ksi

Answer

10,000 ksi

Answer

57,000 ksi

Answer

100,000 ksi

Question 4

Which ASTM standard governs the compressive strength testing of cylindrical concrete specimens?

Accepted Answer

ASTM C39

Answer

ASTM C150

Answer

ASTM C31

Answer

ASTM C78

Question 5

Reinforcing bar (rebar) in the US is designated by bar number. What does the bar number represent?

Accepted Answer

Approximate diameter in eighths of an inch

Answer

Nominal diameter in inches

Answer

Weight per linear foot in pounds

Answer

Cross-sectional area in square inches

Question 6

What role does fly ash play when used in a concrete mix design?

Accepted Answer

It acts as a supplementary cementitious material (SCM)

Answer

It replaces coarse aggregate to reduce weight

Answer

It functions as a chemical accelerating admixture

Answer

It is applied as a curing membrane after placement

Question 7

The flexural strength (modulus of rupture) of concrete is approximately what percentage of its compressive strength?

Accepted Answer

10–15%

Answer

50%

Answer

25%

Answer

1–2%