CSLB Concrete C8 License Practice
Test 1
1. What is the volume of a cylinder if the diameter equals 3
feet and the length equals to 12 feet?: 84.78 cubic 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 = Àx r x rWhere À = 3.14and
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 the length to find the
volume.7.065 x 12 =
84.78Shortcut MethodArea of the circle is 78.5% of the square.
Treat the circle as a square and solve for the area.Find the area of
the square instead of the 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
2. Where are spiral rebar ties used?: In round columns
3. Control joints in sidewalks should be spaced at what
intervals?: 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.
4. One cubic foot of cement weighs approximately:: 95 lbs
5. How many cubic yard of concrete is required for a 4" slab
with the diameter of 15 feet?: 2 ½ cubic yards
Explanation:
Traditional MethodUse the following formula:Area of the circle = Àx r
x rWhere À = 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
6. The normal tolerance for the location of bends and ends of
reinforcing bar is:: +/- 2 inches
7. How many cubic yards of backfill are required for a 3' x 5'
trench, 1500 ft long, with a 1 foot diameter pipe?: 789.72
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: 54=
A5= 35.1
_42 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
Test 1
1. What is the volume of a cylinder if the diameter equals 3
feet and the length equals to 12 feet?: 84.78 cubic 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 = Àx r x rWhere À = 3.14and
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 the length to find the
volume.7.065 x 12 =
84.78Shortcut MethodArea of the circle is 78.5% of the square.
Treat the circle as a square and solve for the area.Find the area of
the square instead of the 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
2. Where are spiral rebar ties used?: In round columns
3. Control joints in sidewalks should be spaced at what
intervals?: 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.
4. One cubic foot of cement weighs approximately:: 95 lbs
5. How many cubic yard of concrete is required for a 4" slab
with the diameter of 15 feet?: 2 ½ cubic yards
Explanation:
Traditional MethodUse the following formula:Area of the circle = Àx r
x rWhere À = 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
6. The normal tolerance for the location of bends and ends of
reinforcing bar is:: +/- 2 inches
7. How many cubic yards of backfill are required for a 3' x 5'
trench, 1500 ft long, with a 1 foot diameter pipe?: 789.72
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: 54=
A5= 35.1
_42 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
