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

What is the minimum clear width of a sidewalk or walk under California Chapter 11B?

• a.36 inches
• b.44 inches
• c.48 inches✓
• d.60 inches

The clear width for sidewalks and walks is 48 inches minimum, with a hardship exception where the enforcing agency determines compliance would be unreasonable. The 36-inch value is the general walking surface width, and 44 inches applies to certain corridors.2025 CBC §11B-403.5.1

Which condition governs placing a fog seal?

• a.Pavement at least 80°F, in winds above 20 mph
• b.Air at least 65°F, with the road dry or damp
• c.Pavement and air at least 60°F and rising, on a dry road surface✓
• d.Pavement and air at least 50°F and rising, on a damp road

Fog seals need both pavement and ambient temperatures of at least 60°F and rising, a dry road, and no rain or freezing within 24 hours, applied in sustained winds under 15 mph. The other combinations mix slurry seal and chip seal conditions or allow high winds.Caltrans 2024 Standard Specifications §37-4.01C(2)

What is the maximum sustained wind speed for applying a fog seal?

• a.Less than 40 mph
• b.Less than 25 mph
• c.Less than 15 mph✓
• d.Less than 5 mph

Fog seal is applied when sustained winds are less than 15 mph, and the work stops if wind blows debris onto the traveled way or disturbs spreading. Winds of 40 mph or 25 mph would carry overspray, and 5 mph is stricter than stated.Caltrans 2024 Standard Specifications §37-4.01C(2)

What rolling sequence finishes an emulsion chip seal before traffic is allowed?

• a.Two coverages of initial rolling with a steel roller, without sweeping
• b.Traffic is left to seat the chips, then the lane is swept
• c.Three coverages with a vibratory steel-drum roller, then sweep
• d.One initial and two final pneumatic-roller coverages, then sweeping the lane✓

The sequence is initial rolling of 1 coverage and final rolling of 2 coverages with pneumatic-tired rollers, then sweeping, a flush coat if specified and removal of the covers. Steel-roller initial rolling with no sweeping leaves loose chips, a vibratory steel roller can crush the chips, and traffic is not the compaction method.Caltrans 2024 Standard Specifications §37-2.01C(4)(d)

What loading and air pressure must the pneumatic-tired rollers used on chip seals carry?

• a.At least 10,000 pounds per wheel, tires at 150 psi
• b.At least 3,000 pounds per wheel at 100 ± 5 psi✓
• c.At least 500 pounds per wheel, tires at 30 psi or foam-filled
• d.A 1,000-pound wheel load at ordinary highway tire pressure

Chip seal rollers carry at least 3,000 pounds on each wheel with tires at 100 ± 5 psi or foam filled. Ten thousand pounds at 150 psi is heavier than the specified load and would crush chips, while 500 pounds at 30 psi and a 1,000-pound load at highway pressure are too light to seat them.Caltrans 2024 Standard Specifications §37-2.01C(2)

How far ahead of the completed initial rolling may chip seal aggregate be spread?

• a.Not more than 250 feet
• b.Not more than 25,000 feet
• c.Not more than 2,500 feet✓
• d.As far as the spreader can run in a day

Aggregate is not spread more than 2,500 feet ahead of the completed initial rolling, so the emulsion does not set before the chips are seated. Two hundred fifty feet is shorter than the stated limit, and 25,000 feet or a day's run lets the emulsion set before the chips are seated.Caltrans 2024 Standard Specifications §37-2.02C(3)

How long should traffic stay off new porous asphalt according to the EPA fact sheet?

• a.24 to 48 hours✓
• b.12 to 18 hours
• c.60 to 90 days
• d.3 to 4 weeks

The EPA fact sheet says contractors should avoid vehicular traffic for 24 to 48 hours after installing porous asphalt. Twelve to 18 hours is shorter than the fact sheet advises, and 3 to 4 weeks and 60 to 90 days are far longer.U.S. EPA, Stormwater BMP: Permeable Pavements

Within what time should pervious concrete be poured after mixing, unless admixtures extend the handling time?

• a.1 hour✓
• b.3 hours
• c.24 hours
• d.15 minutes

The EPA fact sheet says to pour pervious concrete within 1 hour of mixing because of its lower water content, unless admixtures extend the handling time. Three hours and a day are too long, and 15 minutes is the time within which the concrete is typically consolidated after placement.U.S. EPA, Stormwater BMP: Permeable Pavements

A sidewalk has no adjacent curb. At what interval are expansion joints constructed, and how are contraction joints patterned?

• a.200-foot expansion joints; contraction panels of 50 square feet
• b.5-foot expansion joints; contraction panels of 2 to 4 square feet
• c.60-foot expansion joints; panels of 12 to 20 square feet✓
• d.20-foot expansion joints; contraction panels of 100 square feet

Expansion joints are at 60-foot intervals where there is no adjacent curb, and contraction joints create rectangular patterns of 12 to 20 square feet. Twenty feet is the curb contraction spacing, 200-foot and 5-foot expansion intervals are far too wide or too close, and panels of 50, 100 or 2 to 4 square feet do not match the 12 to 20 square-foot pattern.Caltrans 2024 Standard Specifications §73-3.03

Cold planed asphalt pavement is checked after planing. What must be true of the average planed depth?

• a.Equal to or greater than the depth shown on the plans✓
• b.Exactly 0.03 foot less than the depth shown
• c.It need not be measured on the job
• d.Equal to or less than the depth shown

The average cold planed depth must be equal to or greater than the depth shown, even though individual depths may be adjusted by up to 0.03 foot. Planing shallower than shown leaves the overlay too thick or the profile wrong, and measurement is required.Caltrans 2024 Standard Specifications §39-3.04C(2)

What is the same-shift rule for cold planing?

• a.Plane, pave and open to traffic in the same work shift✓
• b.Plane one week and pave during the next week
• c.Plane at night and pave in the following month
• d.Leave the planed surface open until the first rain

Planing is scheduled so that the pavement is planed, the HMA placed and the area opened to traffic in the same work shift; if not, a temporary HMA taper is built and a corrective action plan is submitted. The other schedules leave a drop-off and loose surface under traffic.Caltrans 2024 Standard Specifications §39-3.04A

How far behind the planer may the removal of cold planed material lag?

• a.No more than 500 feet
• b.No more than 5 feet
• c.No more than 50 feet✓
• d.Until the shift ends

Planed material is removed concurrently, with removal not lagging more than 50 feet behind the planer. Five feet is impractical, and 500 feet and end-of-shift removal leave debris on the roadway.Caltrans 2024 Standard Specifications §39-3.04C(3)

A drop-off between existing pavement and a planed area at a transverse joint cannot be avoided before opening to traffic. What is built?

• a.A temporary hot mix asphalt taper✓
• b.A warning sign, because drops under 3 inches are permitted
• c.A vertical wooden bulkhead
• d.A row of cones

A temporary HMA taper to the level of the existing pavement is built and completely removed before the permanent surfacing. Cones or a sign do not remove the drop, a bulkhead is a hazard, and no 3-inch exception exists.Caltrans 2024 Standard Specifications §39-3.04C(4)

How deep is the saw cut at concrete contraction joints before removing part of a curb, sidewalk or driveway for repair?

• a.At least 1/4 inch deep
• b.A saw cut of 1/2 inch
• c.At least 6 inches deep
• d.At least 1-1/2 inches✓

At contraction joints a true line is saw cut at least 1-1/2 inches deep before concrete removal. A quarter inch and a half inch are too shallow to give a clean edge, and 6 inches exceeds the stated depth.Caltrans 2024 Standard Specifications §73-10.03

A rectangular patch of 8 feet by 10 feet is replaced with 3 inches of compacted hot mix weighing 145 pounds per cubic foot. About how many tons are needed?

• a.2.9 tons
• b.14.5 tons
• c.0.73 ton
• d.1.45 tons✓

The volume is 80 × 0.25 = 20 cubic feet, the weight is 20 × 145 = 2,900 pounds, and 2,900 ÷ 2,000 = 1.45 tons. The 2.9 figure divides by 1,000, 14.5 shifts the decimal, and 0.73 halves the thickness.Estimating practice (patch tonnage)

What is the permissible exposure limit for respirable crystalline silica in construction under Cal/OSHA?

• a.25 milligrams per cubic meter, 8-hour average
• b.500 micrograms per cubic meter, 8-hour average
• c.5 micrograms per cubic meter, 15-minute average
• d.50 micrograms per cubic meter, 8-hour average✓

The PEL is 50 micrograms per cubic meter calculated as an 8-hour TWA. Twenty-five milligrams and 500 micrograms are the wrong magnitude, 5 micrograms over 15 minutes is the wrong value and averaging time, and 25 micrograms per cubic meter is the threshold below which the standard does not apply, not the PEL.8 CCR §1532.3

What happens to the detectable warning surface when a curb ramp is removed for repair?

• a.It is omitted if the new ramp is under 6 feet long
• b.It is repainted yellow and left in place on the ramp
• c.It is left in place and the new concrete poured over it
• d.It is removed with the concrete and a new one installed✓

Removal of concrete includes removal of detectable warning surfaces, and a prefabricated surface is installed on the new ramp under the manufacturer's instructions. Burying, painting or omitting it would leave a non-compliant ramp.Caltrans 2024 Standard Specifications §73-10.03

Which feature must a cold planing machine have to control dust and emissions?

• a.A fan that blows the dust to the lane edge
• b.A diesel burner to soften the pavement ahead
• c.A dust-control system, with no fumes or smoke produced✓
• d.A water spray used when neighbors complain

The planing machine must effectively control dust and be operated so that no fumes or smoke are produced, and heating devices are not used. Blowing dust aside is not control, a burner makes fumes and is not allowed, and spraying water only after complaints is not effective control.Caltrans 2024 Standard Specifications §39-3.04C(1)

If the State withholds payment for chip seal work without permanent stripes and markings after the allowed time, how much is withheld?

• a.All remaining payment on the whole contract
• b.5 percent of the whole contract value
• c.50 percent of the estimated value of the unmarked work✓
• d.1 percent per day of the contract value

The Department withholds 50 percent of the estimated value of the completed chip seal work that has not received permanent stripes and markings. All remaining payment, 5 percent of the whole contract and 1 percent per day are not the amount; the withholding is 50 percent and applies only to the unmarked work.Caltrans 2024 Standard Specifications §37-2.01C(1)

HMA is placed on a shoulder less than 5 feet wide outside the traveled way. What equipment is allowed?

• a.A full-width paver with a heated screed and MTV
• b.No hot mix may be placed on narrow shoulders
• c.Hand tools, spread in layers under 1 inch thick
• d.Equipment other than a paver, if finish is uniform✓

On areas less than 5 feet wide outside the traveled way, including shoulders, HMA may be placed in one or more layers with mechanical equipment other than a paver, provided the result is uniformly smooth and textured. A paver with a heated screed and MTV is not mandatory on such narrow areas, hand tools in thin layers are not the only permitted method, and hot mix may be placed on narrow shoulders.Caltrans 2024 Standard Specifications §39-2.01C(1)

On a two-lane road under one-way traffic control, how long must pilot cars route traffic over a new chip seal before the lane opens to uncontrolled traffic?

• a.A minimum of 2 hours✓
• b.A minimum of 24 hours
• c.A minimum of 7 days
• d.At least 5 minutes of travel

After final rolling, traffic is controlled with pilot cars and routed over the new chip seal for a minimum of 2 hours before opening the lane to traffic not controlled with pilot cars. Five minutes is too short for the seal to set, and 24 hours and 7 days are far longer than the stated minimum.Caltrans 2024 Standard Specifications §37-2.01C(4)(d)(ii)

Which classification covers applying directional lines, buttons, markers and arrows on a parking facility surface?

• a.C-12 Earthwork and Paving Contractor
• b.C-34 Pipeline Contractor, trench surfacing
• c.C-32 Parking and Highway Improvement✓
• d.C-27 Landscaping Contractor, grading

The C-32 definition includes directional lines, buttons, markers, signs and arrows on the horizontal surface of a parking facility or roadway, but not re-paving. C-12 lays the pavement, C-34 covers pipeline trenching and its incidental surfacing, and C-27 is landscaping and its grading.CSLB C-32 classification text

Seal coat work will restrict parking on a street. At what spacing are the No Parking - Tow Away signs posted?

• a.At 1,000-foot intervals on the affected streets
• b.At 100-foot intervals on the affected streets✓
• c.At the two ends of the affected street
• d.One sign per block

Signs are posted at 100-foot intervals on the affected streets and must state the dates and hours of the restriction. Signs at 1,000-foot intervals leave long gaps, signs only at the two ends leave the middle of the street unmarked, and one sign per block ignores the 100-foot interval on long blocks.Caltrans 2024 Standard Specifications §37-1.03A

Before traffic or equipment is allowed on concrete pavement (apart from sawing), what strength must it have?

• a.A compressive strength of at least 100 psi
• b.A modulus of rupture of at least 50 psi
• c.A cure time of 24 hours, with no strength test
• d.A modulus of rupture of at least 550 psi✓

Traffic and equipment are kept off until the concrete has attained a modulus of rupture of 550 psi (or the equivalent strength by maturity), with narrow exceptions for sawing and tracked paving equipment at 350 psi. A 100 psi compressive strength and a 50 psi modulus are far too low, and a fixed 24-hour wait without a strength test is not the criterion.Caltrans 2024 Standard Specifications §40-1.03J

Which street sweepers does the State specification allow for sweeping?

• a.A water truck flushing the sediment into the gutter
• b.A steel-broom truck, followed by water flushing
• c.Hand brooms, with the sweepings left in the gutter
• d.Mechanical plus vacuum, vacuum dry, or regenerative-air✓

The specification allows a mechanical sweeper followed by a vacuum-assisted sweeper, a vacuum-assisted dry (waterless) sweeper or a regenerative-air sweeper, and requires at least one on site whenever sweeping is required. Brooms alone and flushing with water do not collect fine sediment.Caltrans 2024 Standard Specifications §13-7.02C