FE Civil Materials practice problems
6 free FE Civil Materials practice problems with answers and full worked solutions. Materials carries 5–8 of the 110 questions on the FE Civil exam (NCEES specification effective July 2020). Pick an answer to check it, then read the worked solution and why each wrong choice is wrong.
6 worked Materials problems
Question 1 of 6
A mix contains 400 lb of cement per cubic yard. Expressed in sacks, the cement content is most nearly:
Show the answer and the reasoning
Why D
Given: 400 lb of cement per cubic yard. Relation: one sack of cement weighs 94 lb. Substitute: 400/94. Result: 4.26 sacks per cubic yard.
Why A is tempting
Divided by 27 as well, though the cement content is already per cubic yard.
Why B is tempting
Inverted the ratio, giving sacks per pound rather than the number of sacks.
Why C is tempting
Used a 100-lb sack. A standard sack of cement weighs 94 lb.
Source NCEES FE Reference Handbook 10.6 — Materials Science; Civil Engineering, concrete and asphalt
Question 2 of 6
An aggregate sample weighs 2475 g saturated surface dry and 1905 g oven dry. Its absorption is most nearly:
Show the answer and the reasoning
Why A
Given: SSD 2475 g, oven dry 1905 g. Relation: absorption = (SSD - OD)/OD x 100, referenced to the dry weight. Substitute: (2475 - 1905)/1905 x 100. Result: 29.9%.
Why B is tempting
Gave the dry fraction of the saturated weight.
Why C is tempting
Added the two weights rather than differencing them.
Why D is tempting
Reported the absorbed water in grams rather than as a percentage.
Source NCEES FE Reference Handbook 10.6 — Materials Science; Civil Engineering, concrete and asphalt
Question 3 of 6
Normal weight concrete has a compressive strength of 3,000 psi. Its modulus of rupture is most nearly:
Show the answer and the reasoning
Why D
Given: f'c = 3,000 psi, normal weight. Relation: fr = 7.5 sqrt(f'c), with f'c in psi. Substitute: fr = 7.5 sqrt(3,000) = 7.5(54.77). Result: fr = 410.8 psi, about 13.7% of the compressive strength.
Why A is tempting
Used the SI coefficient 0.62, which expects megapascals, with a strength in psi.
Why B is tempting
Used a flat 7.5% of the compressive strength. The code relation scales with the square root, not linearly.
Why C is tempting
Applied the lightweight-concrete factor of 0.75 to normal-weight concrete.
Source NCEES FE Reference Handbook 10.6 — Materials Science; Civil Engineering, concrete and asphalt
Question 4 of 6
A cubic yard of air-entrained concrete has an air content of 6.0%. The volume occupied by air is most nearly:
Show the answer and the reasoning
Why A
Given: air content 6.0% of one cubic yard. Relation: air volume = air fraction x 27 ft^3. Substitute: 0.06(27). Result: 1.62 ft^3, which enters the absolute volume balance with the solids.
Why B is tempting
Reported the air content as a percentage.
Why C is tempting
Gave the volume of everything except the air.
Why D is tempting
Applied the 27 conversion twice.
Source NCEES FE Reference Handbook 10.6 — Materials Science; Civil Engineering, concrete and asphalt
Question 5 of 6
A stockpile sample weighs 2625 g wet and 2030 g after oven drying. Its total moisture content is most nearly:
Show the answer and the reasoning
Why B
Given: wet 2625 g, oven dry 2030 g. Relation: MC = (wet - dry)/dry x 100. Substitute: (2625 - 2030)/2030 x 100. Result: MC = 29.3%. Check: less the absorption, this is the free moisture deducted from the mix water.
Why A is tempting
Divided by the wet weight. Moisture content is referenced to the dry weight.
Why C is tempting
Gave the dry fraction of the wet sample.
Why D is tempting
Reported the water weight rather than a percentage.
Source NCEES FE Reference Handbook 10.6 — Materials Science; Civil Engineering, concrete and asphalt
Question 6 of 6
Normal weight concrete has a compressive strength of 4,500 psi. Its modulus of elasticity is most nearly:
Show the answer and the reasoning
Why B
Given: f'c = 4,500 psi, normal weight. Relation: Ec = 57,000 sqrt(f'c), with f'c in psi. Substitute: Ec = 57,000 sqrt(4,500) = 57,000(67.08). Result: Ec = 3,824,000 psi. Check: because of the root, doubling the strength raises the stiffness by only about 41%.
Why A is tempting
Used the SI coefficient 4,700, which expects megapascals, with a strength in psi.
Why C is tempting
Used the unit-weight form with w = 150 pcf. The 57,000 coefficient corresponds to 145 pcf.
Why D is tempting
Used the old rule of thumb E = 1,000 f'c.
Source NCEES FE Reference Handbook 10.6 — Materials Science; Civil Engineering, concrete and asphalt
Going further
Frequently asked questions
How many Materials questions are on the FE Civil exam?
Between 5 and 8 of the 110 questions, according to the NCEES FE Civil specification effective July 2020.
Are these real NCEES exam questions?
No. NCEES does not release its exam questions. These are original FE-style problems written to the NCEES specification and the FE Reference Handbook; every calculated key is checked by two independent solution methods.
Are these Materials practice problems free?
Yes. All 6 problems on this page, with answers and full worked solutions, are free and need no account.
Check where you stand, free
The quick diagnostic is eight FE Civil questions in about ten minutes, with no account. The free mock is a full 110-question, 5 hour 20 minute FE Civil paper with a worked solution for every question.