Exam 1 and 2 Construction Materials
Questions with Verified Answers
A concrete mix has been proportioned to use 300 pounds of water, 2000 pounds of
SSD gravel and 1200 pounds of SSD sand. Today the sand is in SSD condition and the
gravel has a moisture content of 2% and an absorption of 1%, then the new amount of
water in the mix should be___? - ANSWERS280 lb
When performing the Standard Test Method for Bulk Density (Unit Weight) test in lab,
you found the dry-rodded unit weight to be 112 pcf. If the dry bulk specific gravity is
2.663 then the % void volume is
Note: Density of water is 62.4 pcf - ANSWERS32.6%
A 600g sample of aggregate after drying weighs 540 g. It's moisture content is -
ANSWERS11.1%
Outliers are data points that appear to deviate markedly from other data in the sample.
We should always - ANSWERSinvestigate these
A grain size distribution curve that has a high percentage on sample retained by one
sieve is indicating which type of gradation? - ANSWERSuniform
The compound in Portland cement that is primarily responsible for later strength gain in
concrete is - ANSWERSC2S
The modulus of elasticity of concrete (Ec) can be approximated by what formula (in psi
units)? - ANSWERS57,000 * SQRT(f'c)
At cool air temperatures, concrete will - ANSWERShydrate slower than if temperatures
were high
The initial set in normal concrete (without admixtures) in normal conditions would be
approximately how many hours after mixing: - ANSWERS2 - 3 hrs
The tensile strength of concrete is approximately ___________ of its compressive
strength. - ANSWERS10%
ASTM C31 "Making and Curing Concrete Test Specimens" covers how you make a
concrete cylinder. This ASTM standard is an example of a _____________ -
ANSWERSstandard practice
If f'c = 4000 psi for my project the 2 criteria that the ACI uses to determine the
acceptability of concrete in the field are the (1) the average of 3 consecutive tests must
, not be below 4000 psi and (2)__________? - ANSWERSno single test can be less than
3500 psi
Apparent specific gravity of aggregate does NOT include which of the following? -
ANSWERSthe volume of the permeable void spaces in the aggregate
Fly ash, when used in concrete, will - ANSWERSlead to slower strength gains
Which is the smallest size of coarse aggregate in the list below? - ANSWERS57
In a normal curve the amount of area within +/- one standard deviation (i.e. one
standard deviation above and below the mean) is - ANSWERS68%
Admixtures known as conventional (or "standard") water reducers could reduce the
water needed by approximately? - ANSWERS5%
When performing the slump test, the concrete should be rodded - ANSWERS25 times
in each of the 3 layers
Using more water in a concrete mix will - ANSWERSmake the concrete more workable,
reduce the bond strength of the concrete, reduce the strength of the concrete
Air entraining admixtures will - ANSWERSincrease freeze-thaw durability
A 6 x 12 cylinder is tested in compression and fails at 121,560 pounds. The strength of
the concrete is - ANSWERS4300 psi
A sample of compressive strength values of the same laboratory concrete mix has a
mean of 4400 psi with a standard deviation of 440 psi. The ASTM C39 precision
statement sets the limit for coefficient of variation at 2.4%. Which of the following is a
TRUE statement: - ANSWERSThe COV for this sample exceeds the ASTM specified
limit
Dry Bulk specific gravity of aggregate includes which of the following? - ANSWERSthe
volume of the permeable pore spaces in the aggregate
the volume of the aggregate particle (i.e. the "solid rock")
the weight of the aggregate particle (i.e. the "solid rock")
When making a 4 x 8 cylinder it is rodded in how many layers? - ANSWERS2
The following are all species of softwoods: - ANSWERSpine, fir, spruce
Wood is a material which is anisotropic which means that it - ANSWERSexhibits
different properties in different directions
A glue laminated beam is an example of a(n) - ANSWERSengineered wood product
Questions with Verified Answers
A concrete mix has been proportioned to use 300 pounds of water, 2000 pounds of
SSD gravel and 1200 pounds of SSD sand. Today the sand is in SSD condition and the
gravel has a moisture content of 2% and an absorption of 1%, then the new amount of
water in the mix should be___? - ANSWERS280 lb
When performing the Standard Test Method for Bulk Density (Unit Weight) test in lab,
you found the dry-rodded unit weight to be 112 pcf. If the dry bulk specific gravity is
2.663 then the % void volume is
Note: Density of water is 62.4 pcf - ANSWERS32.6%
A 600g sample of aggregate after drying weighs 540 g. It's moisture content is -
ANSWERS11.1%
Outliers are data points that appear to deviate markedly from other data in the sample.
We should always - ANSWERSinvestigate these
A grain size distribution curve that has a high percentage on sample retained by one
sieve is indicating which type of gradation? - ANSWERSuniform
The compound in Portland cement that is primarily responsible for later strength gain in
concrete is - ANSWERSC2S
The modulus of elasticity of concrete (Ec) can be approximated by what formula (in psi
units)? - ANSWERS57,000 * SQRT(f'c)
At cool air temperatures, concrete will - ANSWERShydrate slower than if temperatures
were high
The initial set in normal concrete (without admixtures) in normal conditions would be
approximately how many hours after mixing: - ANSWERS2 - 3 hrs
The tensile strength of concrete is approximately ___________ of its compressive
strength. - ANSWERS10%
ASTM C31 "Making and Curing Concrete Test Specimens" covers how you make a
concrete cylinder. This ASTM standard is an example of a _____________ -
ANSWERSstandard practice
If f'c = 4000 psi for my project the 2 criteria that the ACI uses to determine the
acceptability of concrete in the field are the (1) the average of 3 consecutive tests must
, not be below 4000 psi and (2)__________? - ANSWERSno single test can be less than
3500 psi
Apparent specific gravity of aggregate does NOT include which of the following? -
ANSWERSthe volume of the permeable void spaces in the aggregate
Fly ash, when used in concrete, will - ANSWERSlead to slower strength gains
Which is the smallest size of coarse aggregate in the list below? - ANSWERS57
In a normal curve the amount of area within +/- one standard deviation (i.e. one
standard deviation above and below the mean) is - ANSWERS68%
Admixtures known as conventional (or "standard") water reducers could reduce the
water needed by approximately? - ANSWERS5%
When performing the slump test, the concrete should be rodded - ANSWERS25 times
in each of the 3 layers
Using more water in a concrete mix will - ANSWERSmake the concrete more workable,
reduce the bond strength of the concrete, reduce the strength of the concrete
Air entraining admixtures will - ANSWERSincrease freeze-thaw durability
A 6 x 12 cylinder is tested in compression and fails at 121,560 pounds. The strength of
the concrete is - ANSWERS4300 psi
A sample of compressive strength values of the same laboratory concrete mix has a
mean of 4400 psi with a standard deviation of 440 psi. The ASTM C39 precision
statement sets the limit for coefficient of variation at 2.4%. Which of the following is a
TRUE statement: - ANSWERSThe COV for this sample exceeds the ASTM specified
limit
Dry Bulk specific gravity of aggregate includes which of the following? - ANSWERSthe
volume of the permeable pore spaces in the aggregate
the volume of the aggregate particle (i.e. the "solid rock")
the weight of the aggregate particle (i.e. the "solid rock")
When making a 4 x 8 cylinder it is rodded in how many layers? - ANSWERS2
The following are all species of softwoods: - ANSWERSpine, fir, spruce
Wood is a material which is anisotropic which means that it - ANSWERSexhibits
different properties in different directions
A glue laminated beam is an example of a(n) - ANSWERSengineered wood product
