CONCRETE FLATWORK TECH ACTUAL EXAM TEST
QUESTIONS AND ANSWERS SURE A+
✔✔False (Using them may *increase* the possibility of surface crusting and plastic
shrinkage cracking) - ✔✔(Ch. 9, #12) True or False: Retarding admixtures used in hot-
weather concrete reduce the possibility of surface crusting.
✔✔20 degrees - ✔✔(Ch. 9, #13) During cold weather, placing warm concrete on a cold
subgrade may result in a rubbery, partially set top surface while the underlying concrete
still hasn't set and is bleeding. It's best to have the warm concrete temperature no more
than _____ higher than the temperature of the base.
✔✔can cause dusting of the surface - ✔✔(Ch. 9, #14) Surface carbonation of cold-
weather concrete placed in a heated enclosure:
✔✔50 degrees; 500 psi - ✔✔(Ch. 9, #15) Concrete kept at a temperature of _____ for
one day will usually reach the _______ compressive strength needed to prevent
damage from freezing.
✔✔raveling - ✔✔(Ch. 9, #16) The absence of _________ when joints are wet-sawed is
a good indicator that the concrete has reached the strength needed to prevent damage
from freezing.
✔✔True - ✔✔(Ch. 9, #17) True or False: When using insulated blankets to protect
concrete slabs from freezing, the blankets should be kept tightly against corners and
edges, which are most likely to be damaged by early freezing.
✔✔False (They do not act as anti-freezes because they do not lower the freezing point
of the concrete very much) - ✔✔(Ch. 9, #18) True or False: When added to concrete,
calcium chloride prevents the fresh concrete from freezing in cold weather.
✔✔2% of the cement weight - ✔✔(Ch. 9, #19) When calcium chloride is added to cold-
weather concrete, the weight added should be no more than
✔✔use Type III instead of Type I cement; use additional cement; add an accelerating
admixture to the concrete - ✔✔(Ch. 9, #20) Which of the following can be done to
reduce setting time and increase early strength gain during cold weather, thus reducing
the needed protection period:
✔✔premature finishing; late finishing - ✔✔(Ch. 10, #1) Finishers must "hit the gap" in
the "window of finishability" to avoid __________ ____________ that can result in
surface defects and ________ ___________ that may not achieve the specified flatness
or surface finish.
, ✔✔the slump is high and the high slump isn't caused by admixtures - ✔✔(Ch. 10, #2)
The amount of bleeding increases if
✔✔(Ch. 10, #3) True or False: For a floor that will be hard-troweled, if the concrete
bleeds too much and delays finishing, you should switch to air-entrained concrete. -
✔✔False (switching to air-entrained for this reason is not a good tactic. Entrained air
slows the bleeding rate and increases the likelihood of blistering or delamination.)
✔✔(Ch. 10, #3) True or False: For a floor that will be hard-troweled, if the concrete
bleeds too much and delays finishing, you should switch to air-entrained concrete. -
✔✔False (switching to air-entrained for this reason is not a good tactic. Entrained air
slows the bleeding rate and increases the likelihood of blistering or delamination.)
✔✔True - ✔✔(Ch. 10, #5) True or False: Slow setting increases the "window of
finishability."
✔✔open; rain - ✔✔(Ch. 10, #6) Slow setting increases the risk that an unset ________
surface could be damaged by _______.
✔✔prolonged cold weather when protection is not provided to keep the concrete warm -
✔✔(Ch. 10, #7) Slow setting may be caused by:
✔✔crusting - ✔✔(Ch. 10, #8) When placing concrete in cold weather, heating the
subgrade and keeping the as-delivered concrete as close as possible to the specified
minimum temperature can help to prevent ___________.
✔✔True - ✔✔(Ch. 10, #9) True or False: An admixture that reduces bleeding while
retarding setting will aggravate crusting problems.
✔✔bleed water; air bubbles - ✔✔(Ch. 10, #10) Blisters form when _________
_________ or ________ ___________ are trapped under a troweled surface.
✔✔keep float blades flat and delay troweling as long as possible - ✔✔(Ch. 10, #11) To
minimize chances of surface blisters forming during floor finishing:
✔✔flatten; wood - ✔✔(Ch. 10, #12) If blisters do form, __________ the trowel blades or
reopen the surface with a ______ float and delay further finishing for as long as
possible.
✔✔True - ✔✔(Ch. 10, #13) True or False: Delaminations are caused by a separation
between the surface layer and the underlying concrete, but the separated areas are
larger than blisters and the depth of the separation may be as much as 2 inches.
QUESTIONS AND ANSWERS SURE A+
✔✔False (Using them may *increase* the possibility of surface crusting and plastic
shrinkage cracking) - ✔✔(Ch. 9, #12) True or False: Retarding admixtures used in hot-
weather concrete reduce the possibility of surface crusting.
✔✔20 degrees - ✔✔(Ch. 9, #13) During cold weather, placing warm concrete on a cold
subgrade may result in a rubbery, partially set top surface while the underlying concrete
still hasn't set and is bleeding. It's best to have the warm concrete temperature no more
than _____ higher than the temperature of the base.
✔✔can cause dusting of the surface - ✔✔(Ch. 9, #14) Surface carbonation of cold-
weather concrete placed in a heated enclosure:
✔✔50 degrees; 500 psi - ✔✔(Ch. 9, #15) Concrete kept at a temperature of _____ for
one day will usually reach the _______ compressive strength needed to prevent
damage from freezing.
✔✔raveling - ✔✔(Ch. 9, #16) The absence of _________ when joints are wet-sawed is
a good indicator that the concrete has reached the strength needed to prevent damage
from freezing.
✔✔True - ✔✔(Ch. 9, #17) True or False: When using insulated blankets to protect
concrete slabs from freezing, the blankets should be kept tightly against corners and
edges, which are most likely to be damaged by early freezing.
✔✔False (They do not act as anti-freezes because they do not lower the freezing point
of the concrete very much) - ✔✔(Ch. 9, #18) True or False: When added to concrete,
calcium chloride prevents the fresh concrete from freezing in cold weather.
✔✔2% of the cement weight - ✔✔(Ch. 9, #19) When calcium chloride is added to cold-
weather concrete, the weight added should be no more than
✔✔use Type III instead of Type I cement; use additional cement; add an accelerating
admixture to the concrete - ✔✔(Ch. 9, #20) Which of the following can be done to
reduce setting time and increase early strength gain during cold weather, thus reducing
the needed protection period:
✔✔premature finishing; late finishing - ✔✔(Ch. 10, #1) Finishers must "hit the gap" in
the "window of finishability" to avoid __________ ____________ that can result in
surface defects and ________ ___________ that may not achieve the specified flatness
or surface finish.
, ✔✔the slump is high and the high slump isn't caused by admixtures - ✔✔(Ch. 10, #2)
The amount of bleeding increases if
✔✔(Ch. 10, #3) True or False: For a floor that will be hard-troweled, if the concrete
bleeds too much and delays finishing, you should switch to air-entrained concrete. -
✔✔False (switching to air-entrained for this reason is not a good tactic. Entrained air
slows the bleeding rate and increases the likelihood of blistering or delamination.)
✔✔(Ch. 10, #3) True or False: For a floor that will be hard-troweled, if the concrete
bleeds too much and delays finishing, you should switch to air-entrained concrete. -
✔✔False (switching to air-entrained for this reason is not a good tactic. Entrained air
slows the bleeding rate and increases the likelihood of blistering or delamination.)
✔✔True - ✔✔(Ch. 10, #5) True or False: Slow setting increases the "window of
finishability."
✔✔open; rain - ✔✔(Ch. 10, #6) Slow setting increases the risk that an unset ________
surface could be damaged by _______.
✔✔prolonged cold weather when protection is not provided to keep the concrete warm -
✔✔(Ch. 10, #7) Slow setting may be caused by:
✔✔crusting - ✔✔(Ch. 10, #8) When placing concrete in cold weather, heating the
subgrade and keeping the as-delivered concrete as close as possible to the specified
minimum temperature can help to prevent ___________.
✔✔True - ✔✔(Ch. 10, #9) True or False: An admixture that reduces bleeding while
retarding setting will aggravate crusting problems.
✔✔bleed water; air bubbles - ✔✔(Ch. 10, #10) Blisters form when _________
_________ or ________ ___________ are trapped under a troweled surface.
✔✔keep float blades flat and delay troweling as long as possible - ✔✔(Ch. 10, #11) To
minimize chances of surface blisters forming during floor finishing:
✔✔flatten; wood - ✔✔(Ch. 10, #12) If blisters do form, __________ the trowel blades or
reopen the surface with a ______ float and delay further finishing for as long as
possible.
✔✔True - ✔✔(Ch. 10, #13) True or False: Delaminations are caused by a separation
between the surface layer and the underlying concrete, but the separated areas are
larger than blisters and the depth of the separation may be as much as 2 inches.
