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PE Civil practice questions

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Question 1Civil: Construction

Compared with the Standard Proctor laboratory compaction test, the Modified Proctor test is characterized by which of the following?

  1. A smaller mold and a lighter hammer
  2. Use limited to cohesionless soils
  3. No moisture-density curve is plotted
  4. Higher compactive energy Correct answer.

Explanation

The Modified Proctor test uses a 10-lb hammer with an 18-in. drop, 25 blows per layer in five layers, which imparts roughly 56,250 ft-lb per cubic foot compared with about 12,375 ft-lb per cubic foot for Standard Proctor. Both procedures develop a moisture-density relationship; only the energy input differs.

Question 2Civil: Construction

A slump test performed in accordance with ASTM C143 on fresh concrete provides an indication of which property?

  1. Twenty-eight-day compressive strength
  2. Time of initial set
  3. Entrained air content
  4. Consistency of the fresh mixture Correct answer.

Explanation

The slump test measures the vertical settlement of a molded cone of fresh concrete and is an index of consistency and workability. It gives no direct information on hardened strength, air content, or setting time, each of which requires a separate test.

Question 3Civil: Construction

OSHA excavation standards require excavated spoil and mobile equipment to be kept at least what minimum distance from the edge of an excavation?

  1. 1 ft (0.3 m)
  2. 6 in. (150 mm)
  3. 2 ft (0.6 m) Correct answer.
  4. 5 ft (1.5 m)

Explanation

Spoil piles and equipment must be kept at least 2 ft back from the excavation edge to avoid surcharging the sides and to reduce the chance of material falling into the trench. Where the competent person determines that the setback is inadequate, additional support or a greater distance is required.

Question 4Civil: Construction

In the critical path method, the critical path through a network is the path that:

  1. Has the smallest total direct cost
  2. Contains the greatest number of activities
  3. Passes through the start and finish milestones only
  4. Has the longest total duration Correct answer.

Explanation

The critical path is the longest-duration continuous chain of activities from project start to project finish, and therefore it establishes the shortest possible project duration. Every activity on that path has zero total float, so any delay there delays completion.

Question 5Civil: Construction

For normal weather conditions and Type I cement, ACI 308 recommends a minimum moist-curing period for concrete of:

  1. 14 days
  2. 3 days
  3. 7 days Correct answer.
  4. 28 days

Explanation

ACI 308 recommends moist curing for about 7 days for concrete made with Type I cement under normal conditions. Type III (high-early-strength) cement permits a shorter period of about 3 days, while adverse conditions such as low temperature or aggressive exposure call for longer curing.

Question 6Civil: Construction

Epoxy coating is applied to reinforcing bars primarily to:

  1. Raise the yield strength of the bar
  2. Increase bond with the surrounding concrete
  3. Shorten the required development length
  4. Protect against chloride-induced corrosion Correct answer.

Explanation

An epoxy coating is a barrier that isolates the steel from chlorides and moisture, extending service life in bridge decks, marine work, and other corrosive exposures. Because the coating reduces bond, design provisions actually require longer development and lap lengths for coated bars.

Question 7Civil: Construction

A cut of 1,000 bank cubic yards of soil has a swell factor of 25 percent. What loose volume must be transported?

  1. 1,000 cy
  2. 1,250 cy Correct answer.
  3. 1,333 cy
  4. 750 cy

Explanation

Excavation loosens soil, so the loose volume equals the bank volume multiplied by one plus the swell fraction: 1,000 cy times 1.25 equals 1,250 cy. Haul trucks and load counts must be based on this loose volume, not the in-place cut volume.

Question 8Civil: Construction

OSHA construction standards require conventional fall protection when workers are exposed to an unprotected fall of:

  1. 15 ft or more
  2. 10 ft or more
  3. 4 ft or more
  4. 6 ft or more Correct answer.

Explanation

The construction industry fall-protection trigger is 6 ft or more above a lower level for general walking-working surfaces. The 10-ft threshold applies to specific situations such as scaffold platforms, so the general rule remains 6 ft.

Question 9Civil: Construction

For a concrete mixture, reducing the water-cementitious materials ratio while holding all other constituents constant will generally:

  1. Increase strength and decrease workability Correct answer.
  2. Decrease strength and decrease permeability
  3. Have little effect on strength below 0.60
  4. Increase both strength and workability

Explanation

Lowering the water content reduces porosity of the paste, which raises compressive strength and lowers permeability, but the stiffer mixture is harder to place. That is why water reducers are commonly used to obtain low ratios without sacrificing workability.

Question 10Civil: Construction

A soil sample with an unconfined compressive strength of 2.0 tsf, no fissures, and no water seeping from the excavation face would be classified under OSHA's system as:

  1. Type B
  2. Type C
  3. Stable rock
  4. Type A Correct answer.

Explanation

Type A cohesive soil has an unconfined compressive strength of at least 1.5 tsf and is not fissured or subject to vibration or other weakening factors. A strength of 2.0 tsf with no fissures or seepage satisfies those conditions.

Question 11Civil: Construction

Saw-cut contraction joints in a new concrete pavement should be cut:

  1. Immediately after strike-off while the concrete is still plastic
  2. Just before the pavement is opened to traffic
  3. After the concrete has been moist-cured for 7 days
  4. As soon as the concrete can be cut without raveling Correct answer.

Explanation

Contraction joints must be cut while the concrete is still green, before enough tensile stress develops to produce random cracking, which is typically within about 6 to 24 hours. The controlling criterion is that the saw can advance without tearing the aggregate.

Question 12Civil: Construction

In a pile driving record, the term "set" refers to the:

  1. Elevation of the pile cutoff
  2. Thickness of the pile cushion
  3. Number of blows required per foot of penetration
  4. Permanent penetration per hammer blow Correct answer.

Explanation

Set is the net, permanent advance of the pile for one hammer blow after elastic rebound is accounted for. It is recorded near the end of driving and used with a wave equation or dynamic formula to judge whether the required capacity has been reached.

Question 13Civil: Construction

A field density test gives a dry unit weight of 121.5 pcf, and the laboratory maximum dry unit weight for the same soil is 125.0 pcf. The relative compaction is:

  1. 97.2 percent Correct answer.
  2. 3.5 percent
  3. 102.9 percent
  4. 96.4 percent

Explanation

Relative compaction is the field dry unit weight divided by the laboratory maximum dry unit weight: 121.5 divided by 125.0 equals 0.972, or 97.2 percent. This value is compared directly with the specification requirement, commonly 95 percent or higher.

Question 14Civil: Construction

Concrete for a foundation element must be placed below the water table without dewatering the excavation. The appropriate technique is to:

  1. Place the concrete in thin lifts after the excavation is pumped dry
  2. Allow the concrete to fall freely through the water
  3. Pump the concrete onto the standing water surface
  4. Use a tremie pipe kept embedded in the fresh concrete Correct answer.

Explanation

A tremie is a vertical pipe with a hopper that discharges below the concrete surface, and its lower end must stay buried in the fresh concrete so the lift rises as a continuous mass. This prevents the concrete from passing through water, which would wash out paste and cause segregation.

Question 15Civil: Construction

When using a crane load chart, the allowable load is obtained by deducting from the published capacity:

  1. The weight of all lifting attachments below the boom tip Correct answer.
  2. The load plus the rigging
  3. Only the main hook block
  4. Nothing, because published capacities are net values

Explanation

Load charts give gross capacity, so the weight of the hook block, slings, shackles, spreader beams, and any jib or auxiliary head must be subtracted to find the net load that may be lifted. Exceeding the net value at the working radius overloads the crane.

Question 16Civil: Construction

A deep excavation must be dewatered in a highly permeable sand and gravel deposit, with drawdown needed well below the excavation subgrade. The most suitable system is:

  1. Sump pumping from the excavation bottom
  2. Open pumping from a collection ditch
  3. A wellpoint system on 5-ft centers
  4. Deep wells with submersible turbine pumps Correct answer.

Explanation

Deep wells with submersible pumps can achieve large drawdowns in high-permeability granular deposits because each well has a high yield and a large radius of influence. Wellpoints are generally limited to shallow drawdowns of roughly 15 to 20 ft per stage.

Question 17Civil: Construction

In a slip-critical bolted connection, the installation requirement that distinguishes it from a bearing-type connection is that the bolts must be:

  1. Tensioned to a specified minimum pretension Correct answer.
  2. Torqued until the washer yields
  3. Installed with the threads excluded from the shear plane
  4. Fully embedded in grout after tightening

Explanation

A slip-critical connection transfers load through friction generated by clamp force, so every bolt must be brought to a specified minimum pretension using an approved method such as turn-of-nut, a calibrated wrench, direct-tension indicators, or a tension calibrator. Bearing-type connections need only be snug-tight unless pretension is otherwise required.

Question 18Civil: Construction

A work item has an estimated cost of $180,000 and is bid with a 12 percent markup applied to that cost. The bid price is:

  1. $201,600 Correct answer.
  2. $158,400
  3. $192,000
  4. $216,000

Explanation

A markup applied to cost multiplies the cost by one plus the markup rate: $180,000 times 1.12 equals $201,600. Markup on cost differs from markup on selling price, which would be computed differently.

Question 19Civil: Construction

In-place dry density of a compacted granular base course is normally verified in the field by:

  1. A nuclear gauge or sand cone test Correct answer.
  2. A sieve analysis and Atterberg limits
  3. A laboratory Standard Proctor test
  4. A plate load test

Explanation

Field dry density is measured with a nuclear moisture-density gauge or the sand cone method, and the result is compared with the laboratory maximum dry density to obtain relative compaction. The Proctor test supplies the reference value but is not itself a field measurement.

Question 20Civil: Construction

Air entrainment is specified in concrete primarily to improve:

  1. Resistance to sulfate attack
  2. Pumpability of lean mixes
  3. Durability under freeze-thaw cycling Correct answer.
  4. Early-age strength gain

Explanation

Entrained air creates a system of closely spaced, tiny voids that relieve hydraulic pressure as water freezes in the paste, which greatly improves freeze-thaw durability. A side effect is a small reduction in compressive strength, typically offset by a lower water content.

Question 21Civil: Construction

A trench shield (trench box) installed in an excavation performs which function?

  1. Serves as the permanent earth-retaining structure
  2. Eliminates the need for a competent person on the site
  3. Shields workers from cave-in without shoring the walls Correct answer.
  4. Prevents any lateral movement of the trench walls and eliminates soil loading

Explanation

A trench shield protects workers inside it from soil collapse, but it is not designed to shore the trench walls and the soil may still move against it. The space between the shield and the trench walls must be limited and the shield positioned so workers remain inside it.

Question 22Civil: Construction

A project requires 1,000 compacted cubic yards at 95 percent of a maximum dry unit weight of 120 pcf. The borrow soil has an in-place dry unit weight of 110 pcf. The required bank volume is nearest to:

  1. 1,050 cy
  2. 1,036 cy Correct answer.
  3. 1,000 cy
  4. 965 cy

Explanation

The required dry unit weight in the fill is 0.95 times 120, or 114 pcf, and 1,000 cy is 27,000 cubic feet, so the fill requires 27,000 times 114, or 3,078,000 lb of dry soil. Dividing by the borrow's 110 pcf in-place dry unit weight gives about 27,982 cubic feet, or roughly 1,036 cy.

Question 23Civil: Construction

An activity has 5 days of total float and 2 days of free float. If the activity is delayed 4 days, the effect is that:

  1. Project completion is delayed by the full 4 days of the delay
  2. The successor starts 2 days late; completion is unaffected Correct answer.
  3. Project completion is delayed by the 2 days that exceed the free float
  4. Neither the successor activity nor the project completion date is affected

Explanation

Free float is the delay an activity can absorb without affecting the early start of any successor, and total float is the delay it can absorb without affecting project completion. A 4-day delay consumes the 2 days of free float and then pushes the successor 2 days, but it remains within the 5 days of total float, so the project finish is unchanged.

Question 24Civil: Construction

A concrete package has direct costs of $760,000. Jobsite overhead is 8 percent of direct cost, and home-office overhead plus profit is 12 percent of total cost. The bid price is nearest to:

  1. $897,600
  2. $912,000
  3. $919,300 Correct answer.
  4. $950,000

Explanation

Jobsite overhead of 8 percent is applied to direct cost, giving $760,000 times 1.08, or $820,800. Home-office overhead and profit of 12 percent are then applied to that total cost, giving $820,800 times 1.12, or about $919,300.

Question 25Civil: Construction

A 2-in. compacted asphalt lift, 24 ft wide and 1 mile long, is placed at a compacted density of 145 pcf. The quantity of asphalt mixture required is nearest to:

  1. 1,840 tons
  2. 1,430 tons
  3. 1,280 tons
  4. 1,530 tons Correct answer.

Explanation

The compacted volume is 2/12 ft times 24 ft times 5,280 ft, or 21,120 cubic feet. Multiplying by 145 pcf gives 3,062,400 lb, which divided by 2,000 lb per ton is about 1,531 tons, so 1,530 tons is the required quantity.

Question 26Civil: Construction

Which type of portland cement is specified when high early strength is required?

  1. Type III Correct answer.
  2. Type II
  3. Type I
  4. Type V

Explanation

Type III cement is ground finer and contains a higher proportion of tricalcium silicate, so it gains strength rapidly and is used where early form removal or early service is needed. Type I is general purpose, Type II has moderate sulfate resistance, and Type V has high sulfate resistance.

Question 27Civil: Construction

The slump test performed on fresh concrete in accordance with ASTM C143 is used primarily to indicate:

  1. Initial and final setting time
  2. Entrained air content
  3. Consistency of the fresh mixture Correct answer.
  4. Compressive strength at 28 days

Explanation

The slump test measures the vertical settlement of a molded concrete cone and is an index of the consistency, or workability, of the fresh mixture. It is not a measure of strength, air content, or setting time; those require separate tests.

Question 28Civil: Construction

Under OSHA construction standards, excavated soil and other material must be kept at least what minimum horizontal distance from the edge of an excavation?

  1. 2 ft Correct answer.
  2. 1 ft
  3. 1.5 ft
  4. 3 ft

Explanation

OSHA 1926.651(j)(2) requires that excavated material be placed and kept at least 2 ft back from the edge of the excavation. This setback reduces the surcharge load on the excavation face and prevents spoil from falling back onto workers.

Question 29Civil: Construction

What is the standard nominal thickness of a mortar joint in concrete masonry unit construction?

  1. 5/16 in.
  2. 3/8 in. Correct answer.
  3. 1/2 in.
  4. 1/4 in.

Explanation

Concrete masonry is laid with nominal 3/8 in. mortar joints, which are accounted for in the specified dimensions of the module. Thinner joints may not provide adequate bond and thicker joints reduce compressive strength.

Question 30Civil: Construction

Which item of compaction equipment is best suited to compacting a cohesive silty clay fill?

  1. Pneumatic rubber-tired roller
  2. Vibratory plate compactor
  3. Smooth steel-drum roller
  4. Sheepsfoot roller Correct answer.

Explanation

A sheepsfoot roller has projecting feet that penetrate and knead the lift, which is effective for cohesive soils that need to be remolded and densified by kneading action. Smooth-drum and vibratory compactors are best suited to granular, free-draining materials.

Question 31Civil: Construction

Activity A (4 days) precedes activities B (6 days) and C (3 days). Both B and C precede activity D (5 days). What is the total project duration in working days?

  1. 12 days
  2. 15 days Correct answer.
  3. 18 days
  4. 13 days

Explanation

Two paths exist: A-B-D takes 4 + 6 + 5 = 15 days, and A-C-D takes 4 + 3 + 5 = 12 days. The longer path controls, so the project duration is 15 days.

Question 32Civil: Construction

A concrete wall is 40 ft long, 8 ft high, and 10 in. thick. What volume of concrete, in cubic yards, is required with no allowance for waste?

  1. 8.9 cu yd
  2. 10.7 cu yd
  3. 9.9 cu yd Correct answer.
  4. 9.3 cu yd

Explanation

The volume is 40 ft × 8 ft × (10/12 ft) = 266.7 cu ft. Dividing by 27 cu ft per cubic yard gives 9.88, or about 9.9 cu yd.

Question 33Civil: Construction

A crew consisting of four laborers and one foreman places 120 cu yd of concrete in an 8-hour shift. What is the labor-hour rate for this operation?

  1. 0.17 labor-hours per cu yd
  2. 0.25 labor-hours per cu yd
  3. 0.50 labor-hours per cu yd
  4. 0.33 labor-hours per cu yd Correct answer.

Explanation

Five workers times 8 hours equals 40 labor-hours for the shift. Dividing 40 labor-hours by 120 cu yd gives 0.33 labor-hours per cubic yard.

Question 34Civil: Construction

A trench 6 ft wide, 10 ft deep, and 100 ft long is excavated to receive a 24-in. diameter pipe. Ignoring bedding and initial backfill, what net volume of backfill is required, in cubic yards?

  1. 190 cu yd
  2. 211 cu yd Correct answer.
  3. 205 cu yd
  4. 222 cu yd

Explanation

The trench volume is 6 × 10 × 100 = 6,000 cu ft. The pipe displaces π(1 ft)² × 100 ft = 314 cu ft, leaving 5,686 cu ft, which divided by 27 equals 210.6, or about 211 cu yd.

Question 35Civil: Construction

To prevent segregation, concrete should generally not be allowed to fall freely more than about what height before a drop chute or hopper must be used?

  1. 10 ft
  2. 15 ft
  3. 2 ft
  4. 5 ft Correct answer.

Explanation

ACI placing practice limits free fall to roughly 5 ft (1.5 m). Beyond that height, coarse aggregate tends to separate from the mortar, causing segregation and honeycombing.

Question 36Civil: Construction

A project has an earned value of $480,000, an actual cost of $520,000, and a planned value of $500,000. What is the cost performance index?

  1. 0.92 Correct answer.
  2. 0.96
  3. 1.08
  4. 1.04

Explanation

The cost performance index is earned value divided by actual cost, or 480,000/520,000 = 0.92. A value below 1.0 indicates the work completed cost more than its budgeted value.

Question 37Civil: Construction

For normal-weight concrete made with Type I cement placed at moderate temperature, what is the minimum period of moist curing typically required?

  1. 5 days
  2. 14 days
  3. 7 days Correct answer.
  4. 3 days

Explanation

ACI 308 requires a minimum of 7 days of moist curing for Type I cement at moderate temperatures. The period is shortened to 3 days for Type III cement and extended to 14 days for Type V cement or when temperatures are low.

Question 38Civil: Construction

A concrete mixture for one cubic yard contains 600 lb of cement (specific gravity 3.15), 270 lb of water, and 1,800 lb of coarse aggregate (bulk specific gravity 2.65), with 5 percent entrained air. Using the absolute volume method with a fine aggregate specific gravity of 2.65, what weight of fine aggregate is required?

  1. 980 lb
  2. 1,360 lb
  3. 1,220 lb Correct answer.
  4. 1,100 lb

Explanation

Absolute volumes are cement 600/(3.15×62.4) = 3.05 cu ft, water 270/62.4 = 4.33 cu ft, air 0.05×27 = 1.35 cu ft, and coarse aggregate 1,800/(2.65×62.4) = 10.89 cu ft, totaling 19.62 cu ft. The sand therefore occupies 27 − 19.62 = 7.38 cu ft, which weighs 7.38 × 2.65 × 62.4 = 1,220 lb.

Question 39Civil: Construction

A cohesionless soil has a specific gravity of solids of 2.65 and a void ratio of 0.65. If the upward seepage gradient at the excavation base is 0.50, what is the factor of safety against piping?

  1. 3.3
  2. 1.5
  3. 2.0 Correct answer.
  4. 2.6

Explanation

The critical hydraulic gradient is (Gs − 1)/(1 + e) = (2.65 − 1)/(1 + 0.65) = 1.0. The factor of safety against piping is the critical gradient divided by the actual gradient, or 1.0/0.50 = 2.0.

Question 40Civil: Construction

A load of 8,000 lb is lifted with a two-leg sling in which each leg makes a 60-degree angle with the horizontal. What is the tension in each leg?

  1. 8,000 lb
  2. 9,240 lb
  3. 4,620 lb Correct answer.
  4. 4,000 lb

Explanation

For a symmetric two-leg sling, each leg carries T = W/(2 sin θ), where θ is the angle from the horizontal. Thus T = 8,000/(2 sin 60°) = 8,000/1.732 = 4,620 lb.

Question 41Civil: Geotechnical

A clay sample has a liquid limit of 52 and a plastic limit of 24. What is its plasticity index?

  1. 28 Correct answer.
  2. 52
  3. 24
  4. 76

Explanation

The plasticity index is the range of water content over which the soil remains plastic, computed as PI = LL − PL. Here PI = 52 − 24 = 28, which indicates a medium-to-high plasticity clay.

Question 42Civil: Geotechnical

A dry soil has a void ratio of 0.65. Its porosity is most nearly:

  1. 61%
  2. 24%
  3. 65%
  4. 39% Correct answer.

Explanation

Porosity and void ratio are related by n = e/(1 + e), where the volume of solids is taken as unity. Substituting gives n = 0.65/1.65 = 0.394, or about 39 percent.

Question 43Civil: Geotechnical

Water flows vertically through a sand column 60 cm long with a cross-sectional area of 50 cm². The hydraulic conductivity is 1.5 × 10⁻⁴ cm/s and the total head loss across the column is 30 cm. The flow rate is most nearly:

  1. 3.8 × 10⁻³ cm³/s Correct answer.
  2. 1.9 × 10⁻³ cm³/s
  3. 1.5 × 10⁻⁴ cm³/s
  4. 7.5 × 10⁻³ cm³/s

Explanation

Darcy's law gives Q = k i A, with the hydraulic gradient i equal to head loss divided by flow length, i = 30/60 = 0.5. Thus Q = (1.5 × 10⁻⁴)(0.5)(50) = 3.75 × 10⁻³ cm³/s.

Question 44Civil: Geotechnical

A drained triaxial test on a saturated sand with c′ = 0 reaches failure at σ₃′ = 100 kPa and σ₁′ = 300 kPa. The effective friction angle is most nearly:

  1. 45°
  2. 20°
  3. 15°
  4. 30° Correct answer.

Explanation

For a cohesionless soil the Mohr-Coulomb failure criterion can be written σ₁′/σ₃′ = tan²(45° + φ′/2). With a ratio of 3, 45° + φ′/2 = 60°, so φ′ = 30°.

Question 45Civil: Geotechnical

Which of the following soil conditions is most susceptible to liquefaction during an earthquake?

  1. Loose, saturated fine sand Correct answer.
  2. Stiff, overconsolidated clay
  3. Dense, well-graded gravel
  4. Compacted silty clay

Explanation

Liquefaction requires a loose to medium-dense, saturated, cohesionless soil that tends to contract under cyclic shear, allowing pore pressures to build toward the effective stress. Well-graded gravels drain freely, and stiff clays have cohesion and low permeability, so neither develops rapid pore pressure buildup.

Question 46Civil: Geotechnical

In the Unified Soil Classification System, a soil with more than 50 percent of its material passing the No. 200 sieve is classified as:

  1. Silt or clay Correct answer.
  2. Sand
  3. Gravel
  4. Boulders

Explanation

The USCS first separates coarse-grained from fine-grained soils at 50 percent passing the No. 200 (0.075 mm) sieve. Material finer than that sieve is silt- and clay-sized, so the soil falls in the fine-grained group and is further identified by its plasticity characteristics.

Question 47Civil: Geotechnical

A sand deposit has e_max = 0.90, e_min = 0.45, and an in-situ void ratio of 0.60. Its relative density is most nearly:

  1. 17%
  2. 33%
  3. 67% Correct answer.
  4. 50%

Explanation

Relative density compares the current void ratio with the loosest and densest states: Dr = (e_max − e)/(e_max − e_min). Substituting gives (0.90 − 0.60)/(0.90 − 0.45) = 0.67, a medium-dense condition.

Question 48Civil: Geotechnical

The groundwater table is 3 m below the ground surface. The soil unit weight is 18 kN/m³ above the water table and 20 kN/m³ (saturated) below it. Taking γ_w = 9.81 kN/m³, the effective vertical stress at a depth of 6 m is most nearly:

  1. 85 kPa Correct answer.
  2. 29 kPa
  3. 60 kPa
  4. 114 kPa

Explanation

Total vertical stress is 18(3) + 20(3) = 114 kPa, and the pore pressure at 6 m is 9.81(3) = 29.4 kPa. Effective stress is total stress minus pore pressure, giving about 84.6 kPa.

Question 49Civil: Geotechnical

A sand has D₆₀ = 2.0 mm, D₃₀ = 0.5 mm, and D₁₀ = 0.15 mm. Its coefficient of curvature is most nearly:

  1. 13.3
  2. 0.83 Correct answer.
  3. 1.20
  4. 3.33

Explanation

The coefficient of curvature is Cc = D₃₀²/(D₆₀ × D₁₀). Substituting gives 0.25/(2.0 × 0.15) = 0.83, which falls outside the 1 to 3 range required for a well-graded soil.

Question 50Civil: Geotechnical

A soil has LL = 45 and PI = 22, with 70 percent passing the No. 200 sieve. Using the Casagrande A-line, PI = 0.73(LL − 20), the USCS group symbol is:

  1. ML
  2. CH
  3. CL Correct answer.
  4. MH

Explanation

The A-line value at LL = 45 is 0.73(45 − 20) = 18.3. Because the plasticity index of 22 plots above the A-line, the soil is a clay, and since the liquid limit is below 50 it is a lean clay, CL.