Materials
5–8 of 110 itemsNCEES draws between 5 and 8 of the 110 from this area on any legal paper. Its outline lists 3 sub-topics; the bank holds 36 verified templates against them, which expand to 831 questions.
Sub-topics, from the NCEES outline
- AMix design of concrete and asphalt
- BTest methods and specifications of metals, concrete, aggregates, asphalt, and wood
- CPhysical and mechanical properties of metals, concrete, aggregates, asphalt, and wood
5 worked problems
Real questions from the bank, at the depth the exam asks them. Pick an answer first: the reasoning opens when you do, along with why each wrong answer is tempting.
Question 1 of 5
A 6 in by 12 in concrete cylinder splits under a diametral load of 50,000 lb. Its splitting tensile strength is most nearly:
Concrete cylinder 6 inches in diameter and 12 inches long, loaded along a diametral line so it splits in tension across the vertical plane. Show the answer and the reasoning
Why B
Given: P = 50,000 lb, d = 6 in, L = 12 in. Relation: T = 2P/(pi L d), the tension across the loaded diametral plane. Substitute: T = 2(50,000)/(pi x 12 x 6). Result: T = 442.1 psi. Check: concrete tensile strength runs roughly a tenth of its compressive strength.
Why A is tempting
Omitted the factor of two in the numerator.
Why C is tempting
Used a factor of four.
Why D is tempting
Left pi out of the denominator.
Source NCEES FE Reference Handbook 10.6 — Materials Science; Civil Engineering, concrete and asphalt
Question 2 of 5
A mix design calls for 1900 lb of saturated surface dry aggregate. The stockpile aggregate has a total moisture content of 3.5% and an absorption of 0.5%. The mixing water must be reduced by most nearly:
Show the answer and the reasoning
Why A
Given: 1900 lb of SSD aggregate, total moisture 3.5%, absorption 0.5%. Relation: only the free moisture, total less absorption, reaches the mix water; adjustment = SSD weight x free moisture. Substitute: free = 3.5 - 0.5 = 3.0%; 1900(0.030). Result: reduce the mixing water by 57 lb.
Why B is tempting
Used the total moisture content. The absorbed portion is already held inside the aggregate and does not reach the mix water.
Why C is tempting
Added the absorption to the total moisture rather than subtracting it.
Why D is tempting
Reported the adjusted aggregate batch weight rather than the water adjustment.
Source NCEES FE Reference Handbook 10.6 — Materials Science; Civil Engineering, concrete and asphalt
Question 3 of 5
An aggregate sample weighs 1975 g oven dry, 2450 g saturated surface dry in air, and 1525 g submerged in water. Its bulk specific gravity is most nearly:
Show the answer and the reasoning
Why C
Given: oven dry A = 1975 g, SSD B = 2450 g, submerged C = 1525 g. Relation: bulk SG = A/(B - C); B - C is the water displaced, the bulk volume of the particles. Substitute: 1975/(2450 - 1525) = 1975/925. Result: bulk SG = 2.135.
Why A is tempting
Inverted the ratio, giving a value well below one where a mineral specific gravity near 2.6 is expected.
Why B is tempting
Left the submerged weight out of the denominator. The displaced volume is the difference between the saturated and submerged weights.
Why D is tempting
Used the saturated surface dry weight in the numerator, which gives the saturated surface dry specific gravity instead.
Source NCEES FE Reference Handbook 10.6 — Materials Science; Civil Engineering, concrete and asphalt
Question 4 of 5
A beam deflects 1.5 in immediately under sustained load. The long-term multiplier for creep and shrinkage is 2. The total long-term deflection is most nearly:
Show the answer and the reasoning
Why D
Given: immediate deflection 1.5 in, long-term multiplier 2. Relation: the multiplier gives the additional deflection, so total = immediate x (1 + lambda). Substitute: 1.5(1 + 2). Result: 4.5 in.
Why A is tempting
Divided by the multiplier rather than multiplying.
Why B is tempting
Ignored creep and shrinkage entirely.
Why C is tempting
Reported the additional long-term deflection alone, omitting the immediate part.
Source NCEES FE Reference Handbook 10.6 — Materials Science; Civil Engineering, concrete and asphalt
Question 5 of 5
A mix contains 650 lb of cement per cubic yard at a water-cement ratio of 0.45. The water required is most nearly:
Show the answer and the reasoning
Why A
Given: cement = 650 lb/yd^3, w/c = 0.45. Relation: water = (w/c) x cement. Substitute: water = 0.45(650). Result: 292.5 lb per cubic yard, or 35.1 gallons.
Why B is tempting
Used one minus the ratio.
Why C is tempting
Added the ratio as if it were a weight.
Why D is tempting
Divided by the ratio. With w/c below one, the water weighs less than the cement.
Source NCEES FE Reference Handbook 10.6 — Materials Science; Civil Engineering, concrete and asphalt
Four mistakes that cost the question
Each of these lands on an answer that is offered, so it costs the question outright. The minutes are our estimate of the time each one burns on top, against an average of 2.9 minutes a question (320 minutes for 110).
Costs the question and about 3 min
Correcting batch water for aggregate moisture in the wrong direction
Mix designs assume aggregate in the saturated surface-dry condition. Wet stockpile aggregate brings free water, its moisture content minus its absorption, so the aggregate batch weight goes up and the added water comes down by that amount. Dry aggregate does the reverse. Adding the free water instead of subtracting it is the error the distractors are built on.
Costs the question and about 2 min
Mixing up the three specific gravities
With A the oven-dry weight, B the saturated surface-dry weight and C the submerged weight, bulk specific gravity is A/(B − C), bulk SSD is B/(B − C) and apparent is A/(A − C). All three are offered; know which one the question names.
Costs the question and about 2 min
Dividing a split-cylinder load by the end area
In the splitting tensile test the load acts along a diameter, and the strength is 2P/(πLD), with L the length and D the diameter. Dividing by the end area instead gives the compressive-strength formula and, for a standard 6 by 12 in cylinder, a value four times too large.
Costs the question and about 2 min
Confusing the additional long-term deflection with the total
The long-term multiplier gives the additional deflection from creep and shrinkage, the multiplier times the immediate deflection under sustained load. The total is the immediate deflection plus that. Questions ask for one or the other and offer both, so read whether additional or total is wanted.
Questions about Materials
Do I need to memorise ASTM test procedures?
No. Expect questions on what a test measures and how its result is computed: a cylinder's compressive strength, a split cylinder's tensile strength, a beam's modulus of rupture, an aggregate's absorption or specific gravity, a sieve analysis's fineness modulus.
Which concrete mix design approach does the exam use?
Absolute volume. Each ingredient's volume is its weight divided by its specific gravity times the unit weight of water, and those volumes plus the air add up to the batch, usually one cubic yard, which is 27 ft³. The water-cement ratio fixes the water once the cement content is known.
Is wood on the FE Civil exam?
It is named in the outline's lists of materials for test methods and for physical and mechanical properties, so a wood question is possible. Concrete and asphalt also have the mix design sub-topic to themselves, which is why they dominate study time for this area.
Is Materials the same as the concrete design questions in Structural Engineering?
No. Materials is about the material itself: mix proportions, test results and properties such as modulus and strain at yield. Designing a reinforced concrete beam or column from those properties belongs to Structural Engineering.
How many study hours this area is worth · Using the handbook under the clock