Nevada A-12 Excavating, Grading, Trenching and Surfacing Contractor Examination

A Nevada site requires removal of 800 bank cubic yards (BCY) of clay. If the clay has a swell factor of 25 percent, how many loose cubic yards (LCY) must be hauled?

• A1,200 loose cubic yards
• B1,000 loose cubic yards
• C800 loose cubic yards
• D640 loose cubic yards

A structural pad needs 1,800 compacted cubic yards (CCY) of fill. The borrow soil shrinks 10 percent from bank to compacted measure. How many bank cubic yards (BCY) must be excavated?

• A1,620 bank cubic yards
• B1,980 bank cubic yards
• C2,000 bank cubic yards
• D1,800 bank cubic yards

An embankment requires 2,400 compacted cubic yards (CCY). Borrow shrinks 12 percent from bank to compacted measure and swells 20 percent from bank to loose measure. How many loose cubic yards must be hauled?

• A2,880 loose cubic yards
• B2,727 loose cubic yards
• C3,225 loose cubic yards
• D3,273 loose cubic yards

On a grading plan, what does a cut indicate compared with a fill?

• ACut is existing ground above finish grade that must be excavated; fill is existing ground…
• BCut is imported borrow only; fill is exported spoil only
• CCut is always rock; fill is always topsoil
• DCut and fill are identical terms for any earthmoving

Using the average-end-area method, two cross sections 100 feet apart have end areas of 45 square feet and 63 square feet. What is the volume between the sections in cubic yards?

• A54 cubic yards
• B200 cubic yards
• C108 cubic yards
• D240 cubic yards

A finished driveway rises 6 feet over a horizontal distance of 200 feet. What is the percent grade?

• A2 percent
• B3 percent
• C6 percent
• D12 percent

In earthwork estimating, what do bank, loose, and compacted cubic yards measure?

• ABank is truck volume, loose is stockpile volume, and compacted is rock only
• BAll three terms mean the same volume and are interchangeable
• CBank is after compaction, loose is in-place, and compacted is excavated
• DBank is undisturbed in-place soil, loose is excavated/hauled soil, and compacted is soil…

A 24-foot-wide paved lane is specified with a 2 percent cross slope. What is the elevation difference from crown (or high edge) to the low edge?

• A0.24 feet
• B0.48 feet
• C2.00 feet
• D4.80 feet

A utility trench is 200 feet long, 4 feet wide, and 8 feet deep with vertical sides. What is the excavated volume in cubic yards?

• A178 cubic yards
• B237 cubic yards
• C256 cubic yards
• D640 cubic yards

What is the difference between subgrade and finish grade on an excavating and surfacing project?

• AThe two terms always mean the same elevation
• BFinish grade is only used for landscaping and never for paving
• CSubgrade is the prepared soil surface that will support pavement or base; finish grade is…
• DSubgrade is the top of asphalt; finish grade is the bottom of the excavation

On a Proctor moisture-density curve, what is optimum moisture content?

• AThe moisture content at which soil first becomes saturated
• BAny moisture content above the plastic limit
• CThe moisture content of undisturbed bank soil
• DThe moisture content at which a given compaction effort produces the maximum dry density

A specification requires 95 percent relative compaction based on a laboratory maximum dry density of 120 pounds per cubic foot. What minimum field dry density meets the specification?

• A114 pounds per cubic foot
• B120 pounds per cubic foot
• C95 pounds per cubic foot
• D126 pounds per cubic foot

A 3-foot-thick embankment will be built in compacted lifts of 6 inches. How many compacted lifts are required?

• A3 lifts
• B4 lifts
• C5 lifts
• D6 lifts

Why do earthwork specifications require moisture conditioning before compacting fill?

• ADry soil never needs water and wet soil never needs drying
• BMoisture conditioning replaces the need for roller passes
• CSoil near optimum moisture can be densified more effectively with a given compaction effo…
• DAdding any amount of water always increases dry density without limit

What does a nuclear density gauge typically measure on a compacted soil lift?

• AOnly Atterberg limits
• BOnly the swell factor of borrow
• CThe unconfined compressive strength used for OSHA soil type
• DIn-place wet density and moisture, from which dry density and relative compaction are cal…

On-site cut will yield 4,500 bank cubic yards. That soil shrinks 10 percent from bank to compacted measure. The job needs 4,000 compacted cubic yards of fill. After placing all of the cut in the fill, what is the result?

• AA surplus of about 50 compacted cubic yards
• BA borrow need of 500 compacted cubic yards
• CA surplus of 500 bank cubic yards with no conversion required
• DThe cut and fill are exactly balanced with no surplus

What is backfill in a trenching and surfacing operation?

• AAny cut material that is wasted off site
• BMaterial placed into an excavation after the pipe, structure, or work in the hole is comp…
• COnly native topsoil left in place and never moved
• DThe first lift of hot-mix asphalt on aggregate base

Before placing fill against an existing hillside, why is the slope usually benched?

• ABenches replace the need to compact the new fill
• BOSHA requires every fill slope to be benched regardless of height or soil
• CBenches key the new fill into firm existing ground and reduce the risk of a sliding plane…
• DBenching is only a landscaping texture and has no structural purpose

During rough grading, what is the main reason to maintain temporary drainage swales and avoid trapping water on the work?

• AWater on grade always improves Proctor density without any downside
• BTemporary drainage is required only after the pavement is placed
• CSwales are used only to store borrow for later use
• DStanding water softens subgrade, can halt compaction, and can destabilize slopes and tren…

A 4:1 (horizontal:vertical) cut slope is 12 feet high. What is the horizontal distance from the toe to the top of the slope?

• A3 feet
• B12 feet
• C36 feet
• D48 feet

Why is topsoil usually stripped and stockpiled before mass excavation and structural fill?

• ATopsoil has the same engineering properties as aggregate base
• BTopsoil is organic and compressible and is unsuitable in structural fills, but it is save…
• CTopsoil is the strongest material and must be used in the bottom of all embankments
• DSpecifications forbid moving topsoil under any circumstance

A proof-roll of the subgrade shows pumping and weaving under a loaded truck. What is the usual contractor response before placing base or pavement?

• AIgnore the weaving if the nuclear gauge once passed on a nearby lift
• BFlood the area so the soil reaches saturation before paving
• CRemove, dry, or stabilize the weak material and recompact until the subgrade is firm
• DPlace hot-mix asphalt immediately to seal the wet soil

When is excavated material typically classified as unsuitable for use as compacted structural fill?

• AWhenever it is native soil from the same site
• BOnly when it is granular sand or gravel
• COnly after it has already been compacted to 95 percent
• DWhen it contains excess organics, debris, frozen soil, or is too wet to compact to specif…

In a mass-haul analysis, what is overhaul?

• AHaul of excavated material beyond the free-haul distance specified in the contract, usual…
• BAny truck movement on the project, including deliveries of asphalt
• CThe swell that occurs when bank soil is loaded
• DThe extra compaction passes required after rain

What is the primary purpose of compacting soil in lifts on an excavating and grading project?

• ATo eliminate the need for any testing or inspection
• BTo increase density and strength so the fill can support loads with limited settlement
• CTo increase the swell factor so more trucks are needed
• DTo keep the soil as wet as possible at all times

A cohesive fill is pumping under the sheepsfoot roller and will not gain density. What is the most likely moisture problem?

• AThe roller is too light because pumping always means insufficient roller weight
• BPumping means the soil has already reached 100 percent saturation and is therefore at max…
• CThe soil is wet of optimum and pore pressure is preventing densification
• DThe soil is slightly dry of optimum and only needs more water immediately

How does a modified Proctor test (ASTM D1557) differ from a standard Proctor test (ASTM D698)?

• AModified Proctor uses less energy and always gives a lower maximum dry density
• BThe two tests are identical and the names are interchangeable
• CStandard Proctor is only for asphalt; modified Proctor is only for concrete
• DModified Proctor uses higher compaction energy, producing a higher maximum dry density an…

A parking area 100 feet by 50 feet will be excavated 6 inches to reach subgrade. What is the neat excavation volume in cubic yards?

• A25 cubic yards
• B56 cubic yards
• C93 cubic yards
• D250 cubic yards

A blue-top or finish-grade stake is set to the design pavement or earth surface. If the plans call for 6 inches of aggregate base and 3 inches of asphalt, how far below the blue top should the compacted subgrade be?

• A3 inches below the blue top
• B6 inches below the blue top
• C9 inches below the blue top
• DFlush with the blue top

Field density tests on a sandy fill are consistently below specification even though the roller pattern looks adequate. The soil feels dry and dusty. What should the contractor try first?

• AFlood the lift until free water stands on the surface, then compact immediately
• BSwitch to a sheepsfoot roller only, because sandy soils always require kneading feet
• CAdd water uniformly, mix, and recompact near optimum moisture
• DKeep rolling the dry lift until the gauge passes without adding water

Which machine is primarily used to spread material in thin layers and cut precise finish grades on a roadway or site?

• AHydraulic excavator
• BSheepsfoot roller
• CAsphalt distributor truck
• DMotor grader

Which compactor is most effective on cohesive clay fills?

• ASheepsfoot or padfoot roller
• BSmooth-drum static roller only
• CPneumatic tire roller only
• DAsphalt vibratory finisher only

For moving large volumes of earth several hundred to a few thousand feet, which equipment combination is generally most economical?

• AAsphalt pavers
• BScrapers (self-loading or push-loaded)
• CWalk-behind plate compactors
• DHand shovels and wheelbarrows

Which roller is typically the first choice for compacting clean granular base or sandy fill?

• AConcrete vibrator
• BStatic grid roller used only on hot-mix asphalt surface course
• CSmooth-drum vibratory roller
• DSheepsfoot roller

Which machine is the usual choice for digging a utility trench and placing pipe bedding?

• AMotor grader
• BPneumatic roller
• CBituminous paver
• DHydraulic excavator (trackhoe) or backhoe-loader

What is the primary function of a trench shield (trench box) during excavation?

• ATo protect workers from a cave-in while they work inside the shielded area
• BTo compact the trench bottom to 95 percent relative compaction
• CTo replace the need for any OSHA soil classification or inspection
• DTo serve as a permanent underground retaining wall left in place under the pavement

A scraper load is 15 loose cubic yards. The average cycle time is 3 minutes, and the contractor uses a 50-minute efficiency hour. What is the estimated production?

• A450 loose cubic yards per hour
• B250 loose cubic yards per hour
• C300 loose cubic yards per hour
• D150 loose cubic yards per hour

What is the main use of a water truck on an excavating and grading project?

• ATo compact clay with kneading action
• BTo excavate rock without blasting
• CTo moisture-condition fill and control dust
• DTo apply tack coat to asphalt

In a typical hot-mix asphalt roller train, what is the pneumatic (rubber-tire) roller mainly used for?

• ADigging the trench for the pavement edge drain
• BApplying prime coat
• CReplacing the paver screed
• DIntermediate rolling to knead the mat and improve surface seal and density

What is the function of the paver screed?

• ATo strike off, initially compact, and set the thickness and smoothness of the asphalt mat
• BTo heat and store binder at the plant
• CTo determine OSHA soil type in the subgrade
• DTo saw contraction joints in new concrete pavement

What is the usual sequence of rollers in a hot-mix asphalt breakdown–intermediate–finish train?

• AStatic steel only, used before the paver places the mix
• BVibratory steel-wheel breakdown, pneumatic intermediate, static steel-wheel finish
• CSheepsfoot breakdown, grid intermediate, padfoot finish
• DWater truck breakdown, grader intermediate, excavator finish

Which compaction tool is most appropriate for trench backfill in a tight area next to a pipe?

• AA motor grader moldboard
• BA highway-class pneumatic roller operating on the pipe itself
• CWalk-behind rammer (jumping jack) or small plate/trench compactor
• DA full-size scraper

Dump trucks are rated at 12 cubic yards struck capacity. Soil swells 25 percent from bank to loose. Approximately how many bank cubic yards does one full struck load represent?

• A12.0 bank cubic yards
• B15.0 bank cubic yards
• C8.0 bank cubic yards
• D9.6 bank cubic yards

When is a wheel loader generally a better production choice than a hydraulic excavator?

• ALoading trucks from a stockpile or working a wide, shallow cut on a firm floor
• BDigging a deep, shored utility trench around existing pipes
• CCutting a vertical trench in a narrow easement with poor setup room
• DSetting trench shields in a deep excavation

On a motor grader, what does rotating the circle (drawbar/circle) primarily allow the operator to do?

• ASpray tack coat through the blade
• BChange the moldboard angle so material can be cut, carried, or windrowed as needed
• CVibrate the blade to compact clay like a sheepsfoot
• DMeasure nuclear density of the lift

What is the purpose of laser or GPS machine-control systems on graders, dozers, and excavators?

• ATo replace compaction testing
• BTo notify USA North 811 without a ticket
• CTo hold the cutting edge or bucket to the design surface with fewer stakes and less rework
• DTo classify OSHA soil type automatically

How does a padfoot roller differ in use from a sheepsfoot roller with tapered feet?

• APadfoot rollers are used only on hot-mix asphalt surface courses
• BSheepsfoot rollers are used only on clean, open-graded stone base
• CNeither machine is ever used on clay
• DBoth compact cohesive soils; padfoot drums are common on modern compactors and walk out o…