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CSLB CONCRETE C8 LICENSE PRACTICE TEST
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? ---------CORRECT 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? ----- ----CORRECT 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 - 1 37.505 = 1843.19 sq ft.
Weather conditions may make placing concrete inadvisable, including: ------ ---CORRECT 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? ---------CORRECT 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. 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) What is the spacing of anchor bolts from ends of sill plates? --------- CORRECT ANSWER-----------------4" min, 12" max In a beam not exposed to weather or soil; what is the minimum coverage for #4 reinforcing bar: ---------CORRECT ANSWER-----------------1 inch When welding bars on sight, special attention should be paid to safety and ____________. ---------CORRECT ANSWER-----------------The exact composition of the materials to be welded
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? ---------CORRECT ANSWER----------------- 15 How many cubic yards of concrete is required for a 4" slab with the circumference of 25 feet? ---------CORRECT ANSWER-----------------3/ 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 = 3.98 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. 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. ------- --CORRECT ANSWER-----------------18"...18" How many cubic yards of concrete is required for a 4" slab with the radius of 10 feet? ---------CORRECT ANSWER-----------------3.87 cubic yards
Explanation: Traditional MethodUse the following formula:Area of the circle = π x r x rWhere π = 3.14 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? ---------CORRECT 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? ---------CORRECT 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? --------- CORRECT 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.
How many cubic yard of concrete is required for a 4" slab with the diameter of 15 feet? ---------CORRECT ANSWER-----------------2 ½ cubic yards Explanation: Traditional MethodUse the following formula:Area of the circle = π x r x rWhere π = 3.14 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: ---------CORRECT 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? ---------CORRECT ANSWER-----------------
Explanation: Step 1. Find the net face area of the trench deducting for pipe.Face area including pipe: 3 x 5 = 15 square feetArea of the pipe: 𝐴=𝜋𝑟2A = 3.14 x .5 x .5A = 0.785Find 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. Find the total volume of the backfill.14.215 x 1500 = 21322.5 cubic feetConvert the volume into cubic yards.21322.5 ÷ 27 = 789.72 cubic yards
When can the live load be calculated by multiplying the height, width and length of a pour and dividing by the deadload? ---------CORRECT ANSWER-----------------Never Tensile strength in concrete is achieved by: ---------CORRECT ANSWER---- -------------The use of steel reinforcement. Refer to the house plan. What is the total cost for the foundation slab if the contractor charges $3.54 per square foot? ---------CORRECT ANSWER----- ------------$6524. 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.Calculate the price of the slab.1843.19 sq ft x $3.54 = $6524. What is the minimum spacing of parallel reinforcing bars placed in two or more layers? ---------CORRECT ANSWER-----------------1 inch Explanation: According to the American Concrete Institute, where parallel reinforcement is placed in two or more layers, bars in the upper layers shall be placed directly above bars in the bottom layer with clear distance between layers not less than 1 inch.
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? --------- CORRECT ANSWER-----------------To reduce risk of exposure to the reinforcing. When batching concrete, what percentage of concrete powder is commonly used? ---------CORRECT ANSWER-----------------25% to 40% cement powder The sides of the main field of the slab must be reinforced with an ___ by ___ grid. ---------CORRECT ANSWER-----------------15"...18" How long can a batch of concrete be in the truck before considerations of quality arise? ---------CORRECT ANSWER-----------------45 minutes Pitch in a spiral reinforcing is a measure of: ---------CORRECT ANSWER---- -------------Spacing between turns. The anchor bolt must be embedded ___ into the slab. ---------CORRECT ANSWER-----------------7" What is the purpose of the deformed rebar? ---------CORRECT ANSWER--- --------------Deformations improve the bond between steel and concrete
What would be the easiest way to avoid puddling under a slab? --------- CORRECT ANSWER-----------------Careful grading Air-entraining: ---------CORRECT 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? ---------CORRECT 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? --------- CORRECT ANSWER-----------------Exact batching What is the maximum spacing of the rebar in the stem wall? --------- CORRECT ANSWER-----------------18" Explanation: The code requires additional rebar to be used if the spacing between rebar in the stem wall exceeds 18". What is the area of the circle if the diameter is 20 feet? ---------CORRECT ANSWER-----------------314 sq. ft.
Required reinforcement bar splicing length or lap length is a function of: ---- -----CORRECT ANSWER-----------------ALL
- 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 are normally required to have a minimum cover of at least the diameter of the bundle, except in the case of permanent proximity to earth where the minimum will be: ---------CORRECT ANSWER- ----------------3 inches Releasing agent is used on forms, why is over use a problem? --------- CORRECT 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? --------- CORRECT ANSWER-----------------Depends on finish to be applied. Strength tests are normally: ---------CORRECT 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: --------- CORRECT ANSWER-----------------Being less expensive.
For quick dry applications you would most commonly use which kind of concrete? ---------CORRECT ANSWER-----------------Type 3 What class of formwork is used for temporary or light loads? --------- CORRECT ANSWER-----------------Class I Explanation: Class I - used for temporary or for light loadsClass II - used for structures that will encounter heavy loads Construction joints are: ---------CORRECT ANSWER-----------------Joints designed to separate one pour from another. How many cubic yard of concrete is required for the footing shown, if it is 75 feet long? ---------CORRECT ANSWER-----------------2 ½ cubic yards Explanation: Step 1: Figure out the area of the face of the footing.Top area = 6" x 9" = 54 square inchesBottom area = 6" x 12" = 72 square inchesTotal area = 54
- 72 = 126 square inchesStep 2: Convert square inches into square feet.126 ÷ 144 = 0.875 square feetStep 3: Get volume by multiplying the previous answer by the length.0.875 x 75 = 65.625 cubic feetStep 4: Convert cubic feet into cubic yards.65.625 ÷ 27 = 2.43 cubic yardsSince there is no exact answer, round up the number. Which of the following will cause the concrete to lose its strength? --------- CORRECT ANSWER-----------------Too much water
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? ---------CORRECT 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? --------- CORRECT ANSWER-----------------15" What is the concrete mixture ratio of 1:2:4? ---------CORRECT 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 1:2 ½:5Standard 1:2:4Rich 1:2: What is the minimum concrete cover, if rebar is cast against and permanently exposed to earth? ---------CORRECT 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? ---------CORRECT 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: --------- CORRECT ANSWER-----------------28 days The average deadload of dry concrete, including reinforcement, is: --------- CORRECT ANSWER-----------------150 lbs/sq ft. Green concrete is: ---------CORRECT ANSWER-----------------Concrete that has been treated for water exposure Which of the following has the highest Load Bearing-Value? --------- CORRECT ANSWER-----------------Bedrock What size is the #3 rebar? ---------CORRECT ANSWER-----------------3/8" Explanation: The rebar comes with 1/8" increments. #1 rebar is 1/8", whereas #3 rebar is 3/8" thick.
Proper curing is essential. What factors are most important to consider? ---- -----CORRECT ANSWER-----------------There are many factors, each with appropriate responses What is the maximum spacing of control joints in driveways? --------- CORRECT ANSWER-----------------20' Explanation: The control joints in driveways should be spaced equal to the width of the slab, but the 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? ---------CORRECT 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
The maximum size of the conduit or pipe shall NOT exceed _______ of the thickness of the concrete. ---------CORRECT ANSWER-----------------1/ Which of the following tests for concrete is conducted at the site/field? ------ ---CORRECT 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. --------- CORRECT ANSWER----------------- 85 If the admixtures are used in concrete for the purpose of delayed setting and hardening of concrete, they are called _____________? --------- CORRECT ANSWER-----------------Retarders Which of the following are the general types of vibrating needles that are in use? ---------CORRECT 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? --------- CORRECT 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. ---------CORRECT ANSWER--------------- -- 675
