CSLB C-12 Earthwork and Paving (Trade Exam) — All Questions

Type A hot mix asphalt with unmodified binder will be placed in a 0.20-foot lift. What are the minimum ambient air and surface temperatures?

• a.65°F air and 80°F surface
• b.45°F air and 50°F surface✓
• c.35°F air and 35°F surface
• d.55°F air and 60°F surface

For lifts of 0.15 foot or more with unmodified binder the minimums are 45°F air and 50°F surface. The 55 and 60 degree values are for thinner lifts, 35 is below any minimum, and 65 and 80 degrees are chip seal conditions.Caltrans 2024 Standard Specifications §39-2.02C

What is the minimum thickness of each lift when Type A hot mix is placed in multiple lifts?

• a.0.15 foot✓
• b.0.05 foot
• c.0.30 foot
• d.0.50 foot

When the thickness shown is 0.30 foot or more, multiple lifts of not less than 0.15 foot each are allowed. Thinner lifts cool too quickly, 0.30 foot is the total thickness threshold, and 0.50 foot is the aggregate base layer limit.Caltrans 2024 Standard Specifications §39-2.02C

Where does the roller start on a hot mix mat with a crown or slope?

• a.At the lower edge, moving toward the high side✓
• b.At the lane edge farthest from the traffic
• c.At the high side, moving toward the lower edge
• d.Along the centerline, in either direction

Rolling starts at the lower edge and progresses toward the highest part so that the mat is confined as it is compacted. Starting high would push the mix downhill and leave the edge unsupported.Caltrans 2024 Standard Specifications §39-2.01C(15)(b)

A density core is 94.2 percent of theoretical maximum density. How is the lot paid?

• a.Payment is withheld until another core is taken
• b.It is removed and replaced at the contractor's cost
• c.With a reduction of 0.0125 for each tenth of a percent
• d.In full; 91.0 to 97.0 percent carries no reduction✓

Results from 91.0 to 97.0 percent of theoretical maximum density earn full payment. Reductions begin outside that range, removal applies below 89.0 or above 99.0 percent, and no waiting period is specified.Caltrans 2024 Standard Specifications §39-2.01A(4)(i)(ii)

How must longitudinal joints be placed in the lower layers of a multi-layer hot mix pavement?

• a.Offset by 6 feet from the lane line in each layer
• b.Stacked directly on top of one another in every layer
• c.At the center of each lane in every layer
• d.Alternated at least 0.5 foot to each side✓

Longitudinal joint offsets in lower layers alternate at least 0.5 foot from each side of the lane line, so that joints do not stack and form a weak plane. Stacking joints directly on top of one another and centering them in each lane create a weak plane, and a 6-foot offset from the lane line is not the stated practice.Caltrans 2024 Standard Specifications §39-2.01C(4)(a)

When may new hot mix pavement be opened to traffic?

• a.When it no longer smells strongly of asphalt
• b.After one hour of rolling is complete
• c.When the surface temperature is below 160°F in the sun
• d.When the mid-depth temperature is below 160°F✓

New hot mix may not be opened to traffic until its mid-depth temperature is below 160°F; the surface cools first and is not the measure. One hour of rolling and the loss of the asphalt smell are not criteria.Caltrans 2024 Standard Specifications §39-2.01C(15)(a)

When are contraction joints sawed in concrete pavement?

• a.After the full 28 days of curing
• b.After the slab has already cracked on its own
• c.Before it cracks, once hard enough to saw cleanly✓
• d.Before placement, using a grooving tool on the subbase

Contraction joints are sawed before the slab cracks naturally, but not before the concrete is hard enough to cut cleanly. Waiting for cracks defeats the joint, a groove in the subbase does not make a joint in the slab, and 28 days is far too late.Caltrans 2024 Standard Specifications §40-1.03B(3)

What is the maximum cross slope of an accessible walking surface?

• a.1:48✓
• b.1:20
• c.1:12
• d.1:10

Walking surfaces on an accessible route have a cross slope not steeper than 1:48. The 1:20 figure is the running slope limit, 1:12 is the ramp slope, and 1:10 is the curb ramp flare.2025 CBC §11B-403.3

What is the maximum rise of a single ramp run on an accessible route?

• a.12 inches
• b.60 inches
• c.30 inches✓
• d.48 inches

The rise of any ramp run is 30 inches maximum, after which a landing and another run are required. Twelve inches is lower than the maximum rise allowed, and 48 inches is a ramp width and 60 inches a landing size, so neither measures the rise of a run.2025 CBC §11B-405.6

What is the minimum width of an access aisle serving California car and van parking spaces?

• a.36 inches
• b.48 inches
• c.60 inches✓
• d.96 inches

Access aisles are 60 inches wide minimum. Thirty-six inches is a walkway pinch point, 48 inches is a walk or ramp width, and 96 inches is the aisle width that permits a narrower van space.2025 CBC §11B-502.3.1

What is the maximum slope of the flared sides of a curb ramp?

• a.1:10✓
• b.1:48
• c.1:12
• d.1:20

Curb ramp flares are not steeper than 1:10. The ramp run is 1:12, the counter slope is 1:20, and 1:48 is the maximum cross slope.2025 CBC §11B-406.2.2

What surface does a detectable warning at a curb ramp consist of?

• a.Parallel grooves cut across the ramp
• b.Yellow truncated domes✓
• c.A smooth steel plate
• d.A broom-finished concrete strip

Detectable warnings consist of a surface of truncated domes, and in California they are yellow. A broom finish, a smooth plate and grooves do not provide the specified tactile and visual warning.2025 CBC §11B-705.1

A lot has 60 parking spaces. How many accessible spaces does the California table require?

• a.2
• b.3✓
• c.4
• d.1

A lot of 51 to 75 spaces needs 3 accessible spaces. One is the 1-to-25 row, 2 is the 26-to-50 row, and 4 is the 76-to-100 row.2025 CBC Table 11B-208.2

A new walk meets an existing slab with a 3/8-inch vertical lip. What must be done?

• a.Fill the joint with loose sand and tamp it
• b.Bevel it at 1:2 or flatter, or make it flush✓
• c.Paint the edge yellow to warn pedestrians
• d.Leave it as it is; it is under 1/2 inch high

Changes in level up to 1/4 inch may be vertical, and from 1/4 to 1/2 inch must be beveled no steeper than 1:2. A 3/8-inch vertical lip violates the rule, and sand or paint does not fix the trip hazard.2025 CBC §11B-303.2 and 303.3

What is the temperature requirement for placing slurry seal or micro-surfacing?

• a.Pavement below 40°F and rising
• b.Pavement and air at least 50°F and rising✓
• c.Air at least 60°F and falling
• d.Pavement at least 80°F and falling slowly

Slurry seals and micro-surfacings require both pavement and air temperatures of at least 50°F and rising, with an expected high of at least 65°F in the next 24 hours. The 80°F surface is a chip seal condition, a falling temperature is the wrong direction, and cold pavement stops the emulsion from breaking.Caltrans 2024 Standard Specifications §37-3.01C(5)(b)

Under what weather conditions may asphaltic emulsion be applied for a chip seal?

• a.Air above 120°F, with a surface above 140°F
• b.Air at least 50°F, with the pavement surface dry
• c.Air 65 to 110°F and surface at least 80°F✓
• d.Air 40 to 50°F with a damp pavement surface

Emulsion for the chip seals described is applied when ambient air is 65 to 110°F and the pavement surface is at least 80°F, and not if air is forecast to fall below 39°F within 24 hours. Air above 120°F is outside the window, 50°F air with a dry surface falls short of both minimums, and 40 to 50°F air with a damp surface is far too cold.Caltrans 2024 Standard Specifications §37-2.02C

What should construction staff do with the subgrade soil beneath a permeable pavement?

• a.Seal it with a clay layer
• b.Not compact it✓
• c.Compact it to 100 percent of maximum density
• d.Compact it when dry

The EPA fact sheet says construction staff should not compact the subgrade soil, because the subgrade's infiltration capacity determines how much water can exfiltrate. Heavy compaction, sealing and conditional compaction reduce infiltration.U.S. EPA, Stormwater BMP: Permeable Pavements

Which finishing practice should be avoided when placing pervious concrete?

• a.Curing the concrete after finishing
• b.Floating and troweling the surface✓
• c.Consolidating with a non-vibratory steel roller
• d.Screeding the concrete to height

Floating and troweling can close the surface pores of pervious concrete and are avoided. Screeding to height, consolidating with a non-vibratory steel roller and curing are all used.U.S. EPA, Stormwater BMP: Permeable Pavements

At what interval are contraction joints spaced in a concrete curb under the State specification?

• a.20-foot intervals✓
• b.100-foot intervals
• c.60-foot intervals
• d.5-foot intervals

Curb contraction joints are spaced at 20-foot intervals. Sixty feet is the expansion joint interval for sidewalks with no adjacent curb, 5 feet is far closer than the curb spacing, and 100 feet is far wider.Caltrans 2024 Standard Specifications §73-2.03A

A colored concrete patio of 800 square feet is finished with dry-shake hardener at the minimum rate. How much hardener is used?

• a.60 pounds
• b.480 pounds✓
• c.48 pounds
• d.4,800 pounds

The minimum is 60 pounds per 100 square feet, so 8 × 60 = 480 pounds, applied in two applications. Sixty pounds is one unit, 4,800 and 48 shift the decimal.Caltrans 2024 Standard Specifications §73-4.03

How deep is the saw cut required before a portion of an asphalt concrete facility is removed?

• a.1/2 inch
• b.6 inches
• c.2 inches✓
• d.12 inches

A 2-inch-deep saw cut to a true line along the limits of the removal area is made before removal. Half an inch is too shallow to give a clean edge, while 6 and 12 inches cut deeper than the 2-inch depth stated.Caltrans 2024 Standard Specifications §39-3.01C

One panel of a concrete curb ramp is cracked. What does the State specification require for the repair?

• a.Replace the whole panel between joints✓
• b.Overlay the whole ramp with a thin asphalt layer
• c.Patch the crack with a cement mortar and seal it
• d.Patch the cracked corner of the panel

Repair of any part of a curb, sidewalk, curb ramp, driveway or gutter depression means removing and replacing the entire section between contraction or expansion joints. Patching, overlaying and corner repair leave a weak or non-compliant panel.Caltrans 2024 Standard Specifications §73-10.03

Which practice is prohibited when cold planing asphalt concrete pavement?

• a.Using a heater to soften the pavement✓
• b.Controlling dust from the planing operation
• c.Removing planed material behind the machine
• d.Using automatic grade and slope controls

The specification says not to use a heating device to soften the pavement. Dust control, automatic grade and slope controls and prompt removal of planed material are required.Caltrans 2024 Standard Specifications §39-3.04C(1)

Which statement describes replacement of asphalt concrete surfacing?

• a.A material transfer vehicle on every patch, with cores
• b.Type A hot mix, method compaction, no transfer vehicle✓
• c.Rubberized hot mix in a single thick lift
• d.Compaction accepted by density cores, without rollers

Replacement HMA is Type A, placed with method compaction, and a material transfer vehicle is not used for replacing asphalt concrete surfacing. Cores are not the acceptance method for method compaction, and the specification does not require rubberized mix.Caltrans 2024 Standard Specifications §39-3.02

Base and surfacing are to be removed. To what depth is the removal made?

• a.At least 6 inches below the grade of the existing surfacing✓
• b.2 inches below the existing surfacing, to save backfill
• c.To the bottom of the asphalt layer
• d.3 feet below the pavement surface everywhere

Removal goes to a depth of at least 6 inches below the grade of the existing surfacing, and holes are backfilled with embankment material. Stopping at the bottom of the asphalt layer leaves the base in place, 2 inches below the existing surfacing is shallower than the 6-inch minimum, and 3 feet everywhere is far deeper than the stated depth.Caltrans 2024 Standard Specifications §39-3.05C

After a chip seal has been swept, within how many days must permanent traffic stripes and pavement markings be placed?

• a.6 months
• b.24 hours
• c.10 days✓
• d.60 days

Permanent stripes and markings are placed within 10 days wherever maintenance sweeping is complete, or the owner withholds 50 percent of the value of the unstriped chip seal work. Six months and 60 days are far longer than the allowed time, and 24 hours is shorter than the 10 days the specification allows.Caltrans 2024 Standard Specifications §37-2.01C(1)

By when must soil tracked onto a public street from the job site be removed?

• a.Within 6 hours, and never allowed into a storm drain✓
• b.By the end of the work week, then swept
• c.Within 72 hours, and if the weather is dry
• d.After the project is finished, then swept

Material tracked onto the surfacing must be removed within 6 hours and may not enter storm drains, open drainage facilities or watercourses. The longer periods let sediment wash into drains.Caltrans 2024 Standard Specifications §13-7.01C

A chip seal will affect parking on a residential street. How far ahead must residents be notified and how are signs spaced?

• a.At least 7 days ahead, with signs at 500-foot intervals
• b.The morning of the work, with signs at each end
• c.A printed notice the day after the work, with one sign
• d.24 hours ahead, with signs at 100-foot intervals✓

The contractor posts No Parking - Tow Away signs at 100-foot intervals stating the dates and hours and notifies residents, businesses and local agencies at least 24 hours before starting. Seven days with signs at 500-foot intervals asks for more notice and wider spacing than stated, notice on the morning of the work is too late and signs at the ends leave gaps, and notice after the work gives residents no chance to move their cars.Caltrans 2024 Standard Specifications §37-1.03A

Before a chip seal is applied, what is done to manholes, valve covers and grates in the area?

• a.Paved over, then located later by trial digging
• b.Removed and the openings capped permanently
• c.Left exposed to receive the seal like the roadway
• d.Covered with plastic or paper and referenced✓

Exposed facilities are covered with plastic or oil-resistant construction paper secured by tape or adhesive and referenced with control points so they can be found afterward. Paving over them blindly or leaving them exposed makes them hard to find or coats them.Caltrans 2024 Standard Specifications §37-2.01C(3)

Work will close a sidewalk and the plans do not show a temporary pedestrian access route. What does the State specification require?

• a.A single cone and a sign placed at each end
• b.A route if the closure will last over a month
• c.A flagger who walks pedestrians through the traffic lane
• d.A work plan for a temporary route sealed by a civil engineer✓

If work closes a pedestrian route and no temporary route is shown, a work plan for one is submitted, sealed and signed by an engineer registered as a civil engineer in the State. A cone and sign do not provide a route, there is no one-month threshold, and walking pedestrians through the traffic lane is not an access route.Caltrans 2024 Standard Specifications §12-4.04A(3)

Type A hot mix with unmodified binder will be placed in a single 0.10-foot lift. What minimum air and surface temperatures apply?

• a.50°F air and 55°F surface
• b.55°F air and 60°F surface✓
• c.40°F air and 40°F surface
• d.45°F air and 50°F surface

Lifts thinner than 0.15 foot with unmodified binder need at least 55°F air and 60°F surface. The 45 and 50 degree values are for thicker lifts, 40 and 40 is the warm-mix additive minimum for thick lifts, and 50 and 55 is the modified-binder column for thin lifts.Caltrans 2024 Standard Specifications §39-2.02C

The plans show 0.45 foot of Type A hot mix, placed in two equal lifts. What is the thickness of each lift and the gradation?

• a.0.225 foot, with the 1/2-inch gradation
• b.0.225 foot, with the 3/4-inch gradation✓
• c.0.15 foot, with the 3/4-inch gradation
• d.0.45 foot, with the 1-inch gradation

Two equal lifts are 0.225 foot each, and lifts of 0.20 to less than 0.25 foot use the 3/4-inch gradation. The 1/2-inch gradation is for 0.15 to less than 0.20 foot, 0.15 foot would need three lifts, and a single 0.45-foot lift with the 1-inch gradation ignores the two equal lifts the question describes.Caltrans 2024 Standard Specifications §39-2.02C

A hot mix lift of 0.17 foot is placed. Which gradation does the State specification require when multiple lifts are used?

• a.3/8 inch
• b.1 inch
• c.1/2 inch✓
• d.3/4 inch

Lifts from 0.15 to less than 0.20 foot use the 1/2-inch gradation. The 3/4-inch gradation begins at 0.20 foot, 1 inch is allowed only for 0.25 foot or more, and 3/8 inch is not in the table.Caltrans 2024 Standard Specifications §39-2.02C

How far in front of the loading equipment may hot mix windrowed on the roadway extend?

• a.Not more than 250 feet✓
• b.Not more than 1,000 feet
• c.Not more than 25 feet
• d.500 feet, if the windrow is tarped

Hot mix placed in a windrow may not extend more than 250 feet in front of the loading equipment or material transfer vehicle. Twenty-five feet is too short for production, and 1,000 feet or a tarped 500 feet are longer windrows that let the mix cool.Caltrans 2024 Standard Specifications §39-2.01C(1)

Asphalt binder is used as the tack coat. At what temperature must it be applied?

• a.75 to 130°F
• b.130 to 180°F
• c.400 to 450°F
• d.285 to 350°F✓

Asphalt binder used as tack coat is applied at 285 to 350°F. The 130 to 180°F range is for chip seal emulsions, 75 to 130°F is for quick-setting Grade 1 emulsions, and 400 to 450°F is far too hot.Caltrans 2024 Standard Specifications §39-2.01C(3)(f)

In method compaction, how many coverages does the vibratory breakdown roller make on each layer, and how fast may the pneumatic intermediate roller travel?

• a.3 coverages, and no faster than 15 mph
• b.7 coverages, and no faster than 5 mph
• c.1 coverage, and no faster than 10 mph
• d.3 coverages, and no faster than 5 mph✓

Method compaction calls for 3 coverages with the vibratory breakdown roller, 3 coverages with the pneumatic roller at no more than 5 mph, and 1 coverage with the steel-tired roller. Seven is the total of all three rollers, 15 mph is faster than the pneumatic roller may travel, and one coverage at 10 mph matches neither the breakdown roller's coverages nor the pneumatic roller's speed.Caltrans 2024 Standard Specifications §39-2.01C(15)(b)

A vibratory roller is used as the finish roller on hot mix. What must be done with the vibrator?

• a.It is run at maximum amplitude
• b.It is turned off✓
• c.It is used on the shoulders
• d.It is run at 2,500 vibrations per minute

If a vibratory roller is used as the finish roller its vibrator must be turned off, because finish rolling removes marks rather than adds compaction energy. Running it at full amplitude or rated frequency would mark the surface.Caltrans 2024 Standard Specifications §39-2.01C(15)(a)

A project places 1,500 tons of hot mix subject to density-core acceptance. At one core per 250 tons, how many cores are taken?

• a.4
• b.15
• c.250
• d.6✓

1,500 ÷ 250 = 6 cores. Four ignores the stated frequency, 15 divides by 100, and 250 is the lot size, not the number of cores.Caltrans 2024 Standard Specifications §39-2.01A(4)(i)(ii)

What is the largest vertical longitudinal joint allowed between adjacent lanes open to traffic?

• a.0.50 foot
• b.1.0 foot
• c.0.15 foot✓
• d.0.30 foot if cones are used

A vertical longitudinal joint of more than 0.15 foot is not allowed at any time between adjacent lanes open to traffic. Half a foot and a foot are too large, and 0.30 foot with cones is still twice the limit because cones do not remove the hazard.Caltrans 2024 Standard Specifications §39-2.01C(4)(a)

A concrete pavement crew is interrupted for 35 minutes between truck loads in one lane. What does the specification require?

• a.Adding water to the stiff concrete in place
• b.A transverse construction joint✓
• c.Removing all of the concrete already placed
• d.Continuing with a retarder added to the mix

Placement interrupted by more than 30 minutes requires a transverse construction joint, and concrete may not be retempered, which rules out adding water. A retarder does not extend the 30-minute limit and leaves a cold joint, and removal of everything is not required.Caltrans 2024 Standard Specifications §40-1.03F(1)

What is the minimum surface temperature to maintain on new concrete pavement for the first 72 hours?

• a.80°F
• b.60°F
• c.20°F
• d.40°F✓

The concrete pavement surface is kept at not less than 40°F for the initial 72 hours. Twenty degrees allows freezing, and 60 and 80 degrees are higher than the stated minimum.Caltrans 2024 Standard Specifications §40-1.03J

What is the maximum running slope of an accessible walking surface before it is treated as a ramp?

• a.1:12
• b.1:10
• c.1:48
• d.1:20✓

Walking surfaces on an accessible route have a running slope not steeper than 1:20 (5 percent); steeper surfaces must comply as ramps at 1:12 or flatter. The 1:48 figure is the cross slope, and 1:10 is the curb ramp flare.2025 CBC §11B-403.3

What are the minimum dimensions of a top landing and a bottom landing on an accessible ramp under the 2025 CBC?

• a.Both landings 48 inches wide and 48 inches long
• b.Both landings 36 inches wide and 36 inches long
• c.Top landing 72 inches, bottom landing 60 inches wide
• d.Top 60 inches wide; bottom 72 inches in the run✓

Top landings are 60 inches wide minimum, and bottom landings extend 72 inches minimum in the direction of the ramp run. The other combinations transpose or understate the dimensions.2025 CBC §11B-405.7

Within what distance of a curb ramp must adjoining gutters and road surfaces have a counter slope no steeper than 1:20?

• a.Within 24 inches✓
• b.Within 12 inches
• c.Within 36 inches
• d.Within 48 inches

Counter slopes immediately adjacent to and within 24 inches of the curb ramp must not be steeper than 1:20, and the transitions must be at the same level. Twelve inches is too short to cover the transition, and 36 and 48 inches are longer than the 24 inches stated.2025 CBC §11B-406.5.8

What is the minimum width of a federal (2010 ADA Standards) van parking space with a standard access aisle?

• a.96 inches with a 60-inch aisle
• b.132 inches✓
• c.108 inches
• d.144 inches

The federal standard requires van spaces 132 inches wide (or 96 inches with a 96-inch aisle). The 144-inch figure is California's, 108 inches is the California car-space width, and a 96-inch space with only a 60-inch aisle does not satisfy either standard.2010 ADA Standards §502.2; 2025 CBC §11B-502.2

A shopping lot has 350 spaces. How many accessible spaces and how many van spaces are required under the California table and van rule?

• a.8 accessible, 8 van
• b.8 accessible, 2 van✓
• c.7 accessible, 1 van
• d.9 accessible, 2 van

Lots of 301 to 400 spaces need 8 accessible spaces, and one van space is required for every six accessible spaces or fraction of six, so 8 ÷ 6 rounds up to 2. The 7 and 9 counts belong to the adjacent rows, and 8 van spaces confuses spaces with the van share.2025 CBC Table 11B-208.2 and §11B-208.2.4

A perpendicular curb ramp run is 5 feet wide. What is the minimum size of its detectable warning, excluding flared sides?

• a.36 inches deep and 36 inches wide
• b.36 inches deep and 56 inches wide✓
• c.48 inches deep and 48 inches wide
• d.24 inches deep and 60 inches wide

The warning extends 36 inches in the direction of travel and the full width of the run less 2 inches maximum on each side, so 60 − 4 = 56 inches. Twenty-four inches is the platform edge depth, 36 by 36 inches ignores the full-width rule, and 48 by 48 inches uses the wrong depth and width.2025 CBC §11B-705.1.2.2.1

A ramp must rise 18 inches. What is the minimum run at the maximum slope?

• a.18 feet✓
• b.18 inches
• c.36 feet
• d.9 feet

At 1:12 each inch of rise needs 12 inches of run, so 18 × 12 = 216 inches = 18 feet. Eighteen inches ignores the slope, 9 feet uses 1:6, and 36 feet uses 1:24.2025 CBC §11B-405.2

What must not be placed within a parking access aisle?

• a.A blue painted borderline around the perimeter
• b.Hatched lines in a contrasting color
• c.The words NO PARKING painted on the surface
• d.Detectable warnings or slopes steeper than 1:48✓

Access aisles must be at the same level as the spaces, with changes in level, slopes exceeding 1:48 and detectable warnings not permitted. The blue border, hatching and NO PARKING are required markings.2025 CBC §11B-502.3.3 and §11B-502.4

What is the minimum clear width of a curb ramp run, excluding flared sides?

• a.48 inches✓
• b.32 inches
• c.36 inches
• d.60 inches

The clear width of curb ramp runs, blended transitions and turning spaces is 48 inches minimum. Thirty-six and 32 inches are narrower corridor widths, and 60 inches is a landing dimension.2025 CBC §11B-406.5.2