Materials is 5–8 questions on the stuff civil projects are built from: concrete, asphalt, aggregates, steel and wood. Expect mix-design arithmetic and questions on what a standard test measures.
Updated Oct 29, 2026 · Not affiliated with NCEES.
ExamFE Civil
questions on the exam5–8
problems here15
of 14 sections7
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What the section covers
Three topics in the July 2020 specification:
Mix design of concrete and asphalt.
Test methods and specifications for metals, concrete, aggregates, asphalt and wood.
Physical and mechanical properties of metals, concrete, aggregates, asphalt and wood.
15 materials problems
0 / 15 answered · 0 correct
Question 1 of 15 · Materials · 5–8 items
Which test is used to determine the setting time of hydraulic cement?
Le Chatelier tests soundness (expansion) of cement, and the flask version measures density.
Slump measures the consistency of fresh concrete, not cement setting time.
The Blaine air-permeability test measures cement fineness.
ASTM C191 times the penetration of the Vicat needle into cement paste to find initial and final set.
Question 2 of 15 · Materials · 5–8 items
Trial
Binder Pb (%)
Bulk SG Gmb
Max SG Gmm
Gsb Agg.
Stability (kN)
A
4.8
2.385
2.515
2.68
9.2
B
5.2
2.410
2.515
2.68
8.8
C
5.6
2.430
2.515
2.68
7.5
D
6.0
2.445
2.515
2.68
6.8
An asphalt mix design laboratory tested four trial binder contents. Compute air voids (Va%), voids in mineral aggregate (VMA%), and voids filled with asphalt (VFA%) for each trial. Select the trial that meets all acceptance criteria: Va=3.5–5.0%, VMA≥14.0%, VFA=65–78%, and Marshall stability≥8.0 kN.
Trial B gives Va = 4.17 %, VMA = 14.75 %, VFA = 71.7 % and stability 8.8 kN, all inside the limits.
Trial C meets the voids limits, but its stability of 7.5 kN is below 8.0 kN.
Trial D has Va = 2.8 % (below 3.5), VFA = 80.5 % (above 78) and stability 6.8 kN (below 8.0).
Trial A has Va = 5.17 %, just above the 5.0 % maximum, so only B passes.
Trial A fails air voids: (2.515 − 2.385)/2.515 = 5.17 % > 5.0 %.
Question 3 of 15 · Materials · 5–8 items
The table below shows trial asphalt mixes. Trial X fails the VMA criterion (VMA=13.2%, required ≥14.0%). All other criteria (Va, VFA, stability) pass for Trial X. Recommend the smallest single corrective action and verify it does not create a new failure. Assume increasing binder content by 0.3% will increase VMA by approximately 0.6% and reduce Va by 0.4%, with negligible effect on stability for small changes.
FE Reference Handbook, Civil — asphalt mix volumetrics.
+0.2 % binder adds only 0.4 % VMA, leaving 13.6 %, still short of 14.0 %.
+0.8 % binder fixes VMA (14.8 %) but pushes Va to 3.1 %, below 3.5, and VFA to 78.8 %, above 78, creating two new failures.
Adding fines usually fills voids and lowers VMA; the stem gives no basis for the claimed 1 % rise.
The predicted VMA of 13.5 % is still below 14.0 %, so this does not cure the failure.
+0.4 % binder raises VMA by 0.6 × 0.4/0.3 = 0.8 % to 14.0 % and drops Va to 3.67 %; VFA = 73.8 %, so every criterion passes.
Question 4 of 15 · Materials · 5–8 items
A concrete mix has a cement content of 500 lb/yd³ and a water content of 250 lb/yd³. What is the water-cement ratio?
Given
Cement content = 500 lb/yd³
Water content = 250 lb/yd³
Find
Water–cement ratio w/c
Solution
w/c = mwater/mcement = 250/500 = 0.50
FE Reference Handbook, Civil — concrete mix design.
0.33 divides water by the total of water plus cement (250/750).
w/c = 250/500 = 0.50 by mass.
0.67 divides cement by water plus cement (500/750).
2.00 is the inverse ratio, cement over water.
Question 5 of 15 · Materials · 5–8 items
A lab report for Los Angeles abrasion test (ASTM C131) states that the sample was oven-dried at 105°C for 18 hours and that 5000 revolutions were used instead of the specified 500 revolutions. The specification requires results for acceptance testing. Which statement correctly describes the validity and required action?
Solution
ASTM C131 (small coarse aggregate): 500 revolutions at 30–33 rpm; loss = (original − retained on No. 12)/original × 100. ASTM C535 (large aggregate) uses 1,000.
Abrasion loss is not linear in revolutions, and no standard allows scaling; the procedure was simply not followed.
A split sample tests repeatability; it cannot rescue a result obtained by the wrong procedure.
Drying to constant mass at about 110 °C is normal; the defect is the revolution count.
Documenting a deviation does not make a non-standard result valid for acceptance.
ASTM C131 specifies 500 revolutions; ten times the abrasion invalidates the percent loss, so a new test is required.
Question 6 of 15 · Materials · 5–8 items
A contractor submitted five gradation test results for a gravel lot. The contract specifies that the lot average percent passing the No. 200 sieve must be ≤2.0% with individual samples ≤3.0%. The test results are 1.8%, 2.3%, 2.5%, 1.9%, and 3.2%. What is the correct acceptance decision and next action?
Field sampling notes describe non-random grab sampling from the top of a stockpile and riffle-splitting that produced a 3.2 kg test sample when the method requires 10 kg minimum. What bias is expected, and what is the required corrective action per standard practice?
Solution
ASTM D75: sample stockpiles at several levels with a board or from a loader face; ASTM C702: reduce by splitter to the test mass.
Stockpile segregation is a known systematic bias; non-random grab samples are not acceptable for acceptance.
Coarse particles roll to the toe of a stockpile, so a top grab sample is rich in fines; the remedy is a proper sample (ASTM D75) split to the required mass (C702).
An independent lab testing the same biased sample reproduces the same bias.
Grab samples from a pile top are biased toward fines, and no standard corrects a too-small sample by scaling.
The bias is right, but splitting an undersized, non-random sample cannot fix how it was taken.
Question 8 of 15 · Materials · 5–8 items
Which ASTM test method is used to determine the compressive strength of cylindrical concrete specimens?
Solution
f′c = Pmax/(πD²/4)
Cylinders: 6 × 12 in or 4 × 8 in, tested at 28 days (C31 molding, C39 testing).
C138 covers density (unit weight), yield and air content by gravimetric method.
C143 is the slump test.
C39 is the compressive strength test of cylindrical concrete specimens.
C231 measures air content of fresh concrete by the pressure method.
Question 9 of 15 · Materials · 5–8 items
What is the primary purpose of the slump test for fresh concrete?
Solution
Slump cone: 12 in tall, 8 in base, 4 in top; three layers rodded 25 times; slump = drop of the top in inches.
The slump of a standard cone of fresh concrete (ASTM C143) indicates consistency, a field check on workability and batch-to-batch water.
Setting time of concrete is measured by penetration resistance (ASTM C403).
Air content of fresh concrete uses the pressure (C231) or volumetric (C173) method, not the slump cone.
Strength is measured on hardened cylinders (ASTM C39), not by slump.
Question 10 of 15 · Materials · 5–8 items
In asphalt pavement design, what does the Marshall Stability test primarily measure?
Solution
Marshall test: 4-in specimen, 140 °F (60 °C), loaded at 2 in/min; report stability (lb or kN) and flow (0.01 in). FE Reference Handbook, Civil — asphalt.
Temperature susceptibility is captured by binder grading (PG); the Marshall test runs at a single 60 °C.
Elastic recovery is a binder test (ductilometer) for polymer-modified asphalt.
Permeability of mixes is tested separately; the Marshall test loads the specimen to failure.
Marshall stability is the peak load a compacted specimen carries at 60 °C before flowing; it indexes resistance to rutting and shoving.
Question 11 of 15 · Materials · 5–8 items
What is the water-cement ratio in a concrete mix design primarily responsible for?
Solution
f′c ≈ A/Bw/c (Abrams); ACI tables relate w/c to strength and set maximum w/c by exposure class.
Shrinkage rises somewhat with water content, but w/c is primarily the strength and durability control.
Abrams' law: strength falls as w/c rises, because extra water leaves capillary pores in the hardened paste.
Setting time depends on cement chemistry and admixtures; 'only' misses the dominant effect on strength.
Color comes from cement and aggregate; w/c is not a color control.
Question 12 of 15 · Materials · 5–8 items
In examining the effects of moisture on wood, what mechanism explains the reduction in strength properties as moisture content increases below the fiber saturation point?
Solution
Fiber saturation point ≈ 25–30 % moisture; above it, strength is nearly constant. NDS adjusts design values with the wet-service factor CM.
Walls swell slightly with bound water, but thickness alone does not explain the strength loss.
Absorbed water reduces bonding between chains; it does not create cross-links.
Bound water enters the cell walls and separates the cellulose chains, weakening the hydrogen bonds between them, so strength drops as moisture rises.
Below fiber saturation the lumens hold no free water; the change happens inside the cell walls.
Question 13 of 15 · Materials · 5–8 items
Which test is used to determine the gradation of aggregates?
Solution
Gradation outputs: percent passing, fineness modulus (sum of cumulative retained on standard sieves/100), Cu and Cc. FE Reference Handbook, Geotechnical — grain size.
Sieving through a nested stack (ASTM C136) gives percent passing each size, the gradation curve.
LA abrasion measures toughness and resistance to degradation.
Specific gravity and absorption support mix design volumes, not gradation.
Slump measures fresh concrete consistency.
Question 14 of 15 · Materials · 5–8 items
In the Superpave performance grade (PG) system, what does an asphalt binder grade such as PG 64-22 indicate?
Solution
PG high/low temperatures come from DSR (rutting, fatigue) and BBR (thermal cracking) tests. FE Reference Handbook, Civil — asphalt binders.
Aggregate compatibility is a mix-design concern; the PG designation describes the binder alone.
Penetration grading is the older system; a PG grade is not a penetration value.
PG 64-22 means the binder meets the specification at a high pavement temperature of 64 °C and a low of −22 °C.
Viscosity grading (AC-20 and similar) is a separate older system.
Question 15 of 15 · Materials · 5–8 items
In asphalt mix design, how do aggregate angularity and surface texture affect pavement performance?
Solution
Superpave consensus properties: coarse aggregate angularity (fractured faces), fine aggregate angularity, flat and elongated particles, sand equivalent.
Angular aggregate can raise VMA slightly, but that is not a drawback; water susceptibility depends on binder–aggregate adhesion chemistry.
Angularity has no meaningful link to thermal expansion of the mix.
Rough texture tends to absorb more binder, and surface smoothness is not the effect.
Angular, rough particles lock together and grip the binder, raising rutting resistance and stability.
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Common traps
Mass, not volume. Water-cement ratio is a ratio of masses. A problem that gives gallons of water needs 8.34 lb per gallon first.
Absolute volumes. Each ingredient’s volume is its mass over its specific gravity times the unit weight of water; the volumes plus air must add up to one cubic yard or one cubic meter.
Which specific gravity. SSD-based calculations use the bulk SSD specific gravity, oven-dry ones the bulk dry value. Mixing them shifts every volume.
Design strength and age. Specified concrete strength is the 28-day cylinder strength unless a problem says otherwise.
Asphalt volumetrics. VMA is the air voids plus the effective binder volume, and VFA is the share of VMA filled with binder; compute all three from one consistent set of specific gravities.
Sources: Mamlouk and Zaniewski, Materials for Civil and Construction Engineers; PCA, Design and Control of Concrete Mixtures.
Moisture in the aggregate
Mix designs assume saturated surface-dry (SSD) aggregate. Wet stockpiles carry free water into the batch, so reduce the mixing water and add the same mass to the aggregate weight; dry stockpiles absorb water, so do the opposite. Absorption and moisture content are both percentages of dry mass.
How it connects
Stress-strain curves, phase diagrams, heat treatment and corrosion of metals are taught on FE Mechanical materials. Concrete and steel as structural members are structural; asphalt pavement thickness is transportation.
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