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A series of practice questions and solutions for the cslb concrete c8 license exam. It covers various topics related to concrete construction, including volume calculations, reinforcement, control joints, and concrete properties. Detailed explanations for each question, making it a valuable resource for individuals preparing for the exam.
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-CSLB Concrete C8 License Practice Test 1
-CSLB Concrete C8 License Practice Test 2
-CSLB Concrete C8 License Practice Test 3
-CSLB Concrete C8 License Practice Test 4
CSLB Concrete C8 License Practice Test 1
What is the volume of a cylinder if the diameter is 3 feet and the length equals to 12 feet?
Explanation
There are two ways to solve the problem. However, regardless of which method is used, you need to first determine the area of the circle then multiply it by the length.Traditional MethodUse the following formula:Area of the circle = π x r x rWhere π = 3.14 and radius (r) = 1.5 feet (half of the diameter length)Area = 3.14 x 1.5 x 1.5Area = 7.065 sq. ft. Multiply area by length to find the volume.7.065 x 12 = 84.78 Shortcut Method Area of circle is 78.5% of the square. Work with the circle as a square and solve for the area. Find area of the square instead of circle.3' x 3' = 9 sq. ft.Since circle is 78.5% of the square, multiply area of the square by 78.5% (or.785 if there is no percentage sign on the calculator).9 sq. ft. x.785 = 7.065 square feetMultiply area by the length to find the volume.7.065 x 12 = 84.78 cubic feet
Where are spiral rebar ties used? - ANSWER In round columns
Control joints in sidewalks should be spaced at what intervals? - ANSWER Equal to the width of the slab
Explanation:
Generally the control joints in sidewalks should be spaced equal to the width of the slab, but not more than 6 feet apart.
One cubic foot of cement weighs approximately: - ANSWER 95 lbs
How many cubic yard of concrete is required for a 4" slab with the diameter of 15 feet? - ANSWER 2 ½ cubic yards
Explanation:
Traditional MethodUse the following formula:Area of the circle = π x r x rWhere π = 3. and radius (r) = 7.5 feet (half of the diameter length)Area = 3.14 x 7.5 x 7.5Area = 176.625 sq. ft.Multiply area by the depth of the slab (in feet) to find the volume in cubic feet.176.625 x.333 = 58.82 cubic feetConvert cubic feet into cubic yards.58.82 ÷ 27 = 2.18 cubic yardsSince 2.18 is not a given option, round up the number to 2.5 cubic yardsShortcut MethodThis problem can be solved using a much simpler method. First is to find the area of the square, then convert it into the area of the circle by multiplying it by 78.5%.Area of the square = 15' x 15' = 225 square feetArea of the circle = 225 x .785 = 176.625 square feetDivide the volume by 81 to solve for the cubic yards for a 4" slab.176.625 ÷ 81 = 2.18 cubic yardsSince 2.18 is not a given option, round up the number to 2.5 cubic yards
The normal tolerance for the location of bends and ends of reinforcing bar is: - ANSWER +/- 2 inches
How many cubic yards of backfill are required for a 3' x 5' trench, 1500 ft long, with a 1 foot diameter pipe? - ANSWER 789.
Explanation:
Step 1. Determine the net face area of the trench minus pipe.Face area with pipe: 3 x 5 = 15 square feetArea of the pipe: ????=????????2A = 3.14 x.5 x.5A = 0.785Determine the face area of the trench minus area of the pipe, which will give you the net area for the backfill.15 - 0.785 = 14.215Step 2. Determine the total volume of the backfill.14.215 x 1500 = 21322.5 cubic feetConvert the volume into cubic yards.21322.5 ÷ 27 = 789. cubic yards
There are many ornamental uses of concrete, including casting architectural elements, ornaments, and faux finishes. How would you describe terrazzo in the simplest terms? - ANSWER A special combination of colored rock and glass for floors.
What is the minimum size of anchor bolt can be used in seismic category E? - ANSWER
The building code requires 5/8" anchor bolt to be used in seismic category E.
Construction loads are: - ANSWER The maximum loads to which a structure will ever be subjected.
In some cases it may be necessary to use stronger or double ties. Why? - ANSWER As a safety precaution when workers may need to climb on reinforcement.
What size of rebar is used to reinforce stem wall? - ANSWER #
Explanation:
The code requires ½ inch rebar to be used in stem walls.
On concrete paving or roadway, it is normal to use transverse joints at regular intervals. These joints are best filled and sealed. Why? - ANSWER To reduce risk of exposure to the reinforcing.
When batching concrete, what percentage of concrete powder is commonly used? - ANSWER 25% to 40% cement powder
The sides of the main field of the slab must be reinforced with an ___ by ___ grid. - ANSWER 15".18"
How long can a batch of concrete be in the truck before considerations of quality arise?
Pitch in a spiral reinforcing is a measure of: - ANSWER Spacing between turns.
The anchor bolt must be embedded ___ into the slab. - ANSWER 7"
What is the purpose of the deformed rebar? - ANSWER Deformations improve the bond between steel and concrete
What would be the easiest way to avoid puddling under a slab? - ANSWER Careful grading
Air-entraining: - ANSWER Improves the working life of concrete.
What is the maximum number of parallel bars that can be bundled together and still be considered a single unit? - ANSWER 4 bars
Explanation:
According to the American Concrete Institute, groups of parallel reinforcing bars bundles in contact to act as a unit shall be limited to four in any one bundle.
Shotcrete can be wet or dry. What are the advantages of wet? - ANSWER Exact batching
What is the maximum spacing of the rebar in the stem wall? - ANSWER 18"
Explanation:
The code requires additional rebar to be used if the spacing between rebar in the stem wall exceeds 18".
-Diameter of the reinforced bar.
-Stress in the reinforced bar at the cross section of splicing.
-Bond-strength between the reinforcing bar and the concrete.
Bundled reinforcing bars normally require a minimum cover of at least the diameter of the bundle, except where permanently in close proximity to earth, the minimum will be: - ANSWER 3 inches
Releasing agent is used on forms, why is over use a problem? - ANSWER Oil in the water makes concrete that is less strong.
There are many surface finishes that can be applied to smooth finished concrete, including: Stain, Paint, Stenciling Oil, Varnish, Epoxy. What considerations should be taken into account before application? - ANSWER Depends on finish to be applied.
Strength tests are normally: - ANSWER The average of 2 tests at a specified time, taken from the same pour.
A mix with a higher percentage of rock has the advantage of: - ANSWER Being less expensive.
For quick dry applications you would most commonly use which kind of concrete? - ANSWER Type 3
You have 5 employees that work for eight hours. How much would you have to pay your employees, if one of them is an apprentice who makes $17/hour, supervisor makes $33/hour, and three journeymen make $22/hour? - ANSWER $928.
Explanation:
Apprentice: $17 x 8 hours = $136Supervisor: $33 x 8 hours = $264Journeymen: 3 x $22 x 8 hours = $528Total: $136 + $264 + $528 = $
Refer to the house plan. How many square feet is the foundation slab? - ANSWER 1844 sq ft
Explanation:
The easiest way to solve for the area of the slab is to image a full rectangle of the slab and subtract void areas from the area of the slab.
Rectangle area: 28.167' x 71.5'= 2013.94 sq ftLeft void area: 6.667' x 1.83' = 12.2 sq ftCenter void area: 11.5' x 1.83' = 21.045 sq ftRight void area: 9.167' x 15' = 137.505Net area of the foundation slab: 2013.94 - 12.2 - 21.045 - 137.505 = 1843.19 sq ft.
Weather conditions may make placing concrete inadvisable, including: - ANSWER High winds and high temperatures
Refer to the house plan. How many cubic yards of concrete needs to be ordered for the foundation slab that is 4 inches thick? - ANSWER 23 cubic yards
Explanation:
The easiest way to solve for the area of the slab is to image a full rectangle of the slab and subtract void areas from the area of the slab.
Rectangle area: 28.167' x 71.5'= 2013.94 sq ftLeft void area: 6.667' x 1.83' = 12.2 sq ftCenter void area: 11.5' x 1.83' = 21.045 sq ftRight void area: 9.167' x 15' = 137.505Net area of the foundation slab: 2013.94 - 12.2 - 21.045 - 137.505 = 1843.19 sq ft.Traditional Method:Multiply the area of the slab by the thickness of the slab (in inches).1843.19 x 0.333' = 613.78 cubic feetConvert the volume into cubic yards.613.78 ÷ 27 = 22.73 cubic yards (rounded up to 23 cubic yards)Industry Method:Divide the area by 81 to get cubic yards.1843.19 sq ft ÷ 81 = 22.76 cubic yards (rounded up to 23 cubic yards)
Round up to select the best answer, which is 5.75 cubic yards.
What is the minimum size of anchor bolt can be used in seismic category D? - ANSWER
Explanation:
The building code requires 1/2" anchor bolt to be used in seismic category D or less.
What size of footing required for a 2-story building with a load bearing value of 1,500psf?
How many cubic yards of concrete is required for a 4" slab with the circumference of 25 feet? - ANSWER 3/4 cubic yard(s)
Explanation:
Since the circumference was provided to calculate the area of the circle, we need to figure out the diameter and/or radius to solve the problem.Circumference = 25Diameter = Circumference (25') ÷ π (or 3.14) = 7.96 feetRadius = Diameter (7.96') ÷ 2 = 3. feetTraditional MethodUse the following formula:Area of the circle = π x r x rWhere π = 3.14 and radius (r) = 3.98 feetArea = 3.14 x 3.98 x 3.98Area = 49.74 sq. ft.Multiply area by the depth of the slab (in feet) to find the volume in cubic feet.49.74 x .333 = 16.56 cubic feetConvert cubic feet into cubic yards.16.56 ÷ 27 = 0.61 cu yds (round up to 3/4)Shortcut MethodThis problem can be solved using a much simpler method. First is to find the area of the square, then convert it into the area of the circle by multiplying it by 78.5%.Diameter = 7.96'Area of the square = 7.96' x 7.96' = 63.36 square feetArea of the circle = 63.36 x .785 = 49.74 square feetDivide the volume by 81 to solve for the cubic yards for a 4" slab.49.74 ÷ 81 = 0.61 cu yds (round up to 3/4)
The main field of the slab must be reinforced with an ___ by ___ grid. - ANSWER 18".18"
How many cubic yards of concrete is required for a 4" slab with the radius of 10 feet? - ANSWER 3.87 cubic yards
Explanation:
Traditional MethodUse the following formula:Area of the circle = π x r x rWhere π = 3. and radius (r) = 10 feet (half of the diameter length)Area = 3.14 x 10 x 10Area = 314 sq. ft.Multiply area by the depth of the slab (in feet) to find the volume in cubic feet.314 x .333 = 104.562 cubic feetConvert cubic feet into cubic yards.104.562 ÷ 27 = 3.87 cubic yardsShortcut MethodThis problem can be solved using a much simpler method. First is to find the area of the square, then convert it into the area of the circle by multiplying it by 78.5%.Diameter = radius x 2 = 20'Area of the square = 20' x 20' = 400 square feetArea of the circle = 400 x .785 = 314 square feetDivide the volume by 81 to solve for the cubic yards for a 4" slab.314 ÷ 81 = 3.87 cubic yards
What is the standard overlap for #4 rebar? - ANSWER 15"
Explanation:
According to the California Building Code, the standard overlap should be 30 times the diameter of the rebar.30 x ½" = 15"
At what times, during set-up, is it important to pay special attention to keeping concrete sufficiently moist? - ANSWER In hot and cold weather.
Explanation:
Cold weather reduces air humidity, hot weather increases evaporation.
What is the minimum mixing time for a mixture of 1 cubic yard? - ANSWER 1 minute
Explanation:
Specifications usually require a minimum of 1 minute mixing for mixtures of 1 cu yd capacity. It increases 15 seconds for each additional ½ cu yd of additional mixture.
What class of formwork is used for temporary or light loads? - ANSWER Class I
Please refer to the house plan. How many square feet does the patio cover (excluding sidewalk)? - ANSWER 460 sq ft
Explanation:
Break down the area of the patio into 4 sections as shown in this diagram.
Area A: 34.167 x 9.333 = 318.89 sq ftArea B: 9.167 x 15 = 137.5 sq ftTotal Patio Area: 318.89 + 137.5 = 456.39Since the answer of 456.39 or 457 is not provided, choose the best possible answer which is 460 sq ft.
What is the area of a cylinder that has a radius of 6 inches and height of 8 feet? - ANSWER 25.12 sq. ft.
Explanation:
To solve for the area of a cylinder, multiply circumference by the height of the cylinder. Don't forget that the radius is given in inches, but height is given in feet.Step 1: Find Circumference.Diameter = radius x 2Diameter = 6" x 2 = 12 inches or 1 footCircumference = D x π (or 3.14)1 x 3.14 = 3.14 feetStep 2. Find the Area.Area = circumference x heightArea = 3.14 x 8Area = 25.
Which of the following tests used to measure the consistency of the concrete? - ANSWER Slump test
Explanation:
Slump test is used to measure the consistency of the concrete.Compressive test is used to determine whether a concrete has the specified compressive strength.
What is the minimum width of the footing for a 2-story house? - ANSWER 15"
What is the concrete mixture ratio of 1:2:4? - ANSWER Standard
Explanation:
The mixture ratio of 1:2:4 stands for 1 part cement, 2 parts of sand or fine aggregate, and 3 parts of coarse aggregate.Here is all of the mixture ratios:Lean 1:3:6Medium 1: ½:5Standard 1:2:4Rich 1:2:
What is the minimum concrete cover, if rebar is cast against and permanently exposed to earth? - ANSWER 3 inches
Explanation:
Concrete cover as protection of reinforcement against weather and other effects is measured from the concrete surface to the outermost surface of the steel. This is also known as concrete tolerance for reinforcement. In most cases, this means that rebar should be encased 3 inches in concrete. If the concrete is not in direct contact with soil/weather, then the encasement can be less than 3 inches.
What is the minimum required thickness for a slab? - ANSWER 3 ½"
Explanation:
Although most concrete slabs are 4", according to code the minimum permissible thickness for the slab is 3 ½".
From an engineering perspective, concrete has the advantage of high compressive strength. Maximum strength is reached after: - ANSWER 28 days
The average deadload of dry concrete, including reinforcement, is: - ANSWER 150 lbs/sq ft.
Green concrete is: - ANSWER Concrete that has been treated for water exposure
Which of the following has the highest Load Bearing-Value? - ANSWER Bedrock
maximum permissible spacing is 20 feet.
If the concrete costs $90 per cubic yard, how much would you pay for 2 ½ cubic yards of concrete with a 8.75% CA sales tax? - ANSWER $244.
Explanation:
Calculate the price of the concrete for 2 ½ cubic yards.$90 x 2.5 = $225.00Calculate the sales tax.$225 x 8.75% (or 0.0875) = $19.69Calculate the total price including the sales tax.$225 + $19.69 = $244.
CSLB Concrete C8 License Practice Test 2
The maximum size of the conduit or pipe shall NOT exceed _______ of the thickness of the concrete. - ANSWER 1/
Which of the following tests for concrete is conducted at the site/field? - ANSWER Color Test
Explanation:
Rest of the above are laboratory tests.
If the concrete compressive strength specified is less than 3600 psi, it has the option of being tested at 28 days and is able to accept the concrete if it attains ___________ percentage of the minimum required strength. - ANSWER 85
If the admixtures are used in concrete for the purpose of delayed setting and hardening of concrete, they are called _____________? - ANSWER Retarders
Which of the following are the general types of vibrating needles that are in use? - ANSWER ALL ANSWERS!
-Internal vibrators
-Immersion vibrators
-Surface vibrators
Concrete proportioning is done based on the facilities available at the site. Which are the general proportioning methods used for concrete? - ANSWER ALL OF THESE
-Surface area method
-Mix design based on flexural strength
-Maximum destiny method
The minimum cementitious material that is required for concrete bridging deck is ______________lbs/cu yd. - ANSWER 675
The amount of free water used in concrete shall not exceed ____________ pounds per cubic yard of concrete. - ANSWER 310
Explanation:
If the SCM are added, it can be increased to 20 pounds per each required 100 pounds of cementitious material in excess of 550 pounds per cubic yard.
If the concrete curbs are to be constructed over the existing pavement, _______________ are used to fix them to pavement. - ANSWER Steel dowels
Which of the following is NOT an example of blended cement? - ANSWER Combination of silica fume and chlorine fluoride
Explanation:
Blended cement is a combination of either Type || or Type V cement with any of the SCM
-Temperature
Which of the following is NOT a property of concrete? - ANSWER High tensile strength
The concrete work is done in freezing zones, it gets cured by ______________. - ANSWER Steam
Explanation:
It is done by heating concrete by steam or using alternating current, so that water content in the concrete is not increased.
Coarse aggregate in concrete is the material that is retained in sieve number ____________. - ANSWER #
Explanation:
The one which passes through sieve #4 is the fine aggregate.
All of the structural steel is considered satisfactory even if it is rusted, but still meets the density requirements, except ___________________. - ANSWER Pre stressing steel
Explanation:
If the pre stressing steel is rusted, it cannot be used since it does not meet the compliance requirements.
The compressive strength of concrete when treated with a 4" cube is always ____________ than when tested with a 6" cube. - ANSWER More
The practice of making concrete to achieve the stipulated minimum strength and durability and to make concrete in the best economical manner is called _________________. - ANSWER Mix design
Explanation:
Mix design uses the theoretical calculations to get the desired higher strength in concrete but yet consuming minimum cement.
What is the purpose of using SCM in concrete other than meeting workability requirements? - ANSWER To avoid emissions:
The cement production accounts for 7% of the GHG
If the contractor transports the concrete, what is the time required on the concrete after it has caught under normal conditions? - ANSWER Before 1 1/2 hours
Answer Before 250 drum revolutions
What is NOT an important reason to use SCM in concrete? - ANSWER Short curing period
The rough concrete finishes are generally appropriate for surfaces subject to _______________. - ANSWER Traction
Why would the cylindrical/circular columns be chosen over the square/rectangular columns? - ANSWER Circular columns carry more load.
Explanation:
For the given cross section area, circular columns carry more load as compared to square/rectangular columns.
The diameter of the vibration needle to be used for concrete vibration for slab is ______________ inch. - ANSWER 3/4" (20mm)
Explanation: