Concrete Flatwork Technician and Flatwork Finisher Practice Test

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• What contingency percentage is recommended for large orders to account for subgrade settlement, uneven subgrade, spillage, and waste?
• What tool is used immediately after screeding to smooth the surface?
• When using a magnesium bull float, leaving a small unfloated section and waiting for bleed water in that section can help determine if the magnesium float is ________ the surface.
• For the metric calculation, what is the thickness of the slab measured in meters?
• What does measuring the gap under a 10-ft straightedge determine?
• Contraction joints are used to what?
• True or False: If the subbase surface for a slab-on-ground is too low, the slab will be thicker.
• _____ bull floats are less likely to seal the surface.
• True or False: Contraction joints spaced closely together are less likely to crack between joints.
• Before concreting, water should be applied to the subgrade in a manner that avoids puddles and soft mud.
• Which of the following would best describe a potential surface issue when warm concrete is placed on a cold subgrade and the top remains soft while the base continues to set?
• True or False: The standard spacing rule for contraction joints expresses spacing in feet as 2 to 3 times the slab thickness in inches.
• Direct chute placement may be impossible when:
• If a floor shows Ff value low but Fl value high, the floor is:
• Early-entry, dry-cut saws usually cut to a maximum depth of how many inches?
• When concrete is placed by crane and bucket, buckets must never be lifted over ________ or over ______ paths.
• All concrete that will be subject to freezing when moist or be exposed to deicing salts should contain which admixture?
• Air-entrained concrete is not recommended for use in concrete slabs finished by repeated steel troweling passes.
• In hot weather, finishing as fast as possible and protecting against moisture loss will help prevent which two issues?
• Floor flatness measurements taken more than 72 hours after concrete placement are the best measure of the finishers' skills.
• True or False: Bull floating must be done after all of the bleed water has evaporated from the surface.
• F-number testing should preferably be done within how many hours after placement, and never later than how many hours after placement?
• Where should the finisher's request to add water to the concrete truck on site be addressed?
• Carbonation of fresh concrete can cause dusting. Which other condition can contribute to dusting?
• Retarding admixtures used in hot-weather concrete reduce the possibility of surface crusting.
• The statement "The amount of bleeding increases if the slump is high and the high slump isn't caused by admixtures" is true or false?
• In hot weather, wet-cut saws can saw contraction joints as early as how many hours after finishing?
• When guiding a concrete truck near a 6-ft (2 m)-deep excavation, the truck wheels closest to the excavation should be how many feet away from the edge?
• Slow setting increases the risk that an unset surface could be damaged by which condition?
• Tools commonly used for hand spreading concrete in slabs include:
• When concrete for a slab placement will be discharged from the truck chute, truck arrivals should usually be spaced about how many minutes?
• Which movement must isolation joints permit?
• When calcium chloride is added to cold-weather concrete, the weight added should be no more than what percent of the cement weight?
• Which statement is a common example of load transfer across construction joints?
• Which combination of conditions can help reduce variations in color for floors during placing and finishing?
• Excessive bleeding in concrete can delay finishing and affect surface finish.
• For an inch-pound calculation, a concrete slab 6 in thick, 200 ft long, and 100 ft wide with a 10% waste factor requires approximately how many cubic yards?
• When one bent or broken blade on a double- or triple-rotor troweling machine is replaced _____ blades should be replaced.
• True or False: Slabs at isolation joints must be free to move horizontally but not vertically.
• Craze cracks on floors are likely to occur if which conditions are present?
• True or False: Before a concrete slab on ground is placed under severe drying conditions that threaten plastic shrinkage cracking, water should be sprayed on the subgrade until puddles are formed and the surface is soft.
• When formed with a groover, the groover bit should cut to what fraction of the slab thickness?
• To avoid low spots when using hand-operated straightedges, workers should ensure there is always enough concrete ahead of the straightedge.
• Blisters form when which of the following are trapped under a troweled surface?
• Finishing outside the window of finishability can lead to surface defects and failure to meet flatness.
• Wood hand floats are best for ______ concrete.
• Why is placement faster when there is room for two concrete trucks ready to discharge into a pump hopper?
• Which statement about the effect of slump on curling is correct?
• What thickness of a layer of compactible manufactured sand (with rock dust) is placed on the vapor retarder before concrete placement when direct contact is not required?
• To minimize shrinkage and reduce cracking and curling, which measures should be used?
• Which defect is defined as a separation between the surface layer and the underlying concrete, potentially larger than blisters?
• On soft concrete, a hard, sharp turn with the rider should be used to fill depressions that the finisher can see.
• True or False: The groover depth commonly used for contraction joints is 1/4 the slab thickness.
• An edger is placed flat on the surface before edging and then tilted up slightly in the direction the tool is moved.
• Which soils require kneading action of a sheepsfoot roller for compaction?
• Delaying final troweling until the surface sets will improve flatness.
• Edging at side forms is most commonly performed on which surfaces?
• When boom pumps are used to place concrete, two important equipment features are ____ reach and delivery ______.
• During hot weather concreting, if a truckload is near the 90-minute limit when discharged and appears stiff as it flows down the chute, what is your main concern?
• ___________ joints are stopping places for a day's work.
• Can portland cement concrete set and harden while underwater?
• Which material is less likely to seal the surface when used as a bull float?
• For a metric calculation, a slab 150 mm thick, 60 m long, and 30 m wide with a 10% waste factor requires approximately how many cubic meters?
• Floating and troweling a concrete slab too soon is likely to cause __________ and __________.
• Truck-mounted conveyors are especially useful on jobs with ______ __________ such as warehouse slabs when the building is enclosed prior to placement.
• What is the purpose of finishing in two directions (parallel and perpendicular to the side forms) when machine floating or troweling slabs?
• Which factor is noted as a contributing factor to color variation if the temperature is not kept fairly constant?
• Using accelerated methods in cold weather reduces the needed protection period.
• Fly ash may be added to concrete from a fly ash silo at the batch plant or from a silo containing a ______ cement.
• Early-entry, dry-cut saws have a skid plate that helps prevent which issue at the cut edges?
• In the context of color variation control, which factor is directly associated with reducing color variation?
• When hand floating, float and trowel blades may be of different sizes, but finishers should always start with the ________ size and then move to the _________ size.
• The reason test cylinders are cured under the same conditions as the in-place concrete is to ensure that the test results are:
• Delaminations are especially likely to occur when which type of concrete is finished with multiple machine passes with the trowel blades?
• Power trowels can be used for which finishing steps?
• A floor with Ff 40 and Fl 40 is considered:
• After the waiting period, floating is done to embed large aggregate particles beneath the surface mortar layer.
• True or False: When hand finishing, finishers usually float and then steel trowel an area before moving their knee boards.
• True or False: The isolation joint depth statement that it should extend to one-quarter depth is false.
• Plastic shrinkage cracks occur when the slab surface is drying faster than the bleedwater is rising to the surface.
• Which statement best describes control of slab curling in low-slump concrete?
• Delaying final troweling until the surface sets is likely to reduce floor flatness.
• Hand trowels used for the first troweling should be short and narrow to increase the pressure on the concrete surface.
• F(f) numbers indicate floor surface smoothness or flatness.
• Which condition would make direct chute placement from the truck especially challenging?
• One disadvantage of using trailer pumps for slab-on-ground placements is:
• Oversanding in concrete mixes is associated with which problems in the floor?
• Drawings for slabs-on-ground may require that reinforcing steel be discontinued (cut) so it doesn't pass through the joint.
• The window of finishability is the period during which finishing must occur to avoid surface defects.
• Darbies are long, hand-held floats that are particularly useful near side forms because:
• If blisters do form, which action should you take?
• Which factors justify ordering more concrete than the measured volume?
• Darbies are long, hand-held floats that are:
• The spacing of contraction joints is often based on the rule that the spacing in feet should be 2 to 3 times the slab thickness in inches.
• Most concrete used in slabs on ground has coarse aggregate with a maximum size of which range?
• The primary purpose of adding an air-entraining agent to concrete for freeze-thaw resistance is to which of the following?
• A drying period following curing increases resistance to damage caused by freezing and thawing.
• For slabs with many protruding pipes, which tool is preferred for smoothing over a bull float?
• Which term describes substances used to slow the evaporation of water from concrete?
• Finishing the concrete while bleed water is on the surface is associated with which phenomenon?
• True or False: Contraction joints are sometimes called control joints.
• Troweling follows immediately after _________, and no troweling should ever be done unless the surface has first been _________.
• True or False: Craze cracking is likely if concrete dries too soon after finishing.
• True or False: Float blades for power troweling machines are wider than trowel blades and turned up on the edges to prevent them from digging into the surface.
• Finishing during the window of finishability should avoid which problems?
• Tilt of a trowel blade is excessive if the leading edge is more than _____ inch above the concrete surface.
• Which action helps prevent crusting when placing concrete in cold weather?
• When using a magnesium bull float, sealing the concrete surface is less likely if you:
• What is the primary function of welded wire reinforcement in slabs-on-ground that are considered unreinforced?
• Concrete is ready for floating when the bleed water sheen is gone and the finisher can walk on the slab leaving about a what depth footprint?
• What tool is used to assess floor flatness and levelness with a long straightedge?
• Surface carbonation of cold-weather concrete placed in a heated enclosure can cause which surface condition?
• True or False: Slowing the concrete delivery rate to match worker output is a valid solution when finishing is behind due to faster setting and a short-handed crew.
• After the waiting period, which operation is performed on the surface of the concrete?
• Floating is also used to compact and further consolidate the surface in preparation for other finishing.
• What do Ff and Fl numbers represent?
• Which practice is most associated with preventing surface blisters during finishing?
• Which of the following is commonly used to hand spread concrete in slabs?
• If contraction joints are sawed too late, _____ may occur.
• Dark and light areas on a concrete slab may indicate that the concrete was cured with plastic sheeting.
• Slow setting increases the window of finishability. Which statement is correct?
• During hand finishing, what is the typical sequence of operations on the area being worked?
• When using insulated blankets to protect concrete slabs from freezing, the blankets should be kept tightly against which areas?
• During diurnal temperature variation, it may be necessary to saw every 3rd or 4th joint before sawing the intermediate joints.
• Pan floats increase floor flatness numbers by approximately how many points when used?
• When only parts of a concrete floor are exposed to sun or wind coming through a door opening, those parts will often _____ and _____ faster.
• If a slab on ground will not be exposed to sulfates, which cement type is most likely used?
• Which finishing operations affect floor flatness?
• Early-entry, dry-cut saws can reduce the waiting period before sawing to as little as how many hours in hot weather and about how many hours in cold weather?
• Fresnos are long-handled trowels with blades 24 to 48 in. long that are used:
• Contraction joints can be formed by grooving or by sawing.
• In the given calculations, why is a waste factor included when determining concrete volume?
• Isolation joint material should extend from the top of the slab to what depth?
• True or False: Contraction joints can be formed by a groover.
• True or False: While machine floating, if the machine digs in or disrupts the level of the surface, stop floating and wait until the concrete surface is stiffer.
• Type III cement is designed to achieve higher early strength than Type I cement.
• Why might reinforcing steel be discontinued so it does not pass through a joint, according to typical drawings?
• Why are larger trowels used for the first troweling?
• A fine broom finish is occasionally required for interior flatwork.
• For a floor that will be hard-troweled, if the concrete bleeds too much and delays finishing, switching to air-entrained concrete is recommended.
• Excessive edging pressure near corners can cause which problem?
• What is considered the best defense against scaling of exterior air-entrained slabs?
• Which statement best describes subbase compaction for different soils?
• True or False: Edging and jointing is not required on most floors and should not be done unless specified.
• Curing compounds should not be used on exterior concrete placed during the fall in cold-winter areas because they may not wear off in time to let the concrete dry.
• True or False: If concrete is setting slowly, floating should be done when the finisher's footprint is 1/2 inch or more.
• Changes in slump most often represent changes in the amount of ______ in the mixture.
• After the waiting period, floating is done to remove slight humps to produce a plane, level surface.
• When some areas of a floor are machine floated and troweled, but other areas must be hand floated and troweled due to penetrations, which property is likely to differ among areas?
• If you're making float passes with a riding machine and running at full speed, what should you do when you see that some of the concrete ahead is still wet?
• A large concrete placement using the same mix is delivered across multiple days. What factor could contribute to color variation despite sameness of the mix?
• A floor with Ff = 48 and Fl = 16 is?
• Wood hand floats are best for which condition?
• Groovers are used primarily to:
• If the slab does not require direct contact with the vapor retarder, what method helps reduce curling?
• Even when using the same source materials and proportions, color variation can still occur due to differences in:
• Before concreting, workers should check the elevation of the subbase by:
• True or False: Construction joints can be made to act as isolation joints or contraction joints.
• In cold weather, the subgrade soil must be free of _____ before concrete placing begins.
• Chatter or washboard marks on a finished surface are caused by:
• There should be no holes punched in the vapor retarder.
• Delays in discharging concrete trucks can result in the concrete being hard to pump, place, and finish.
• When ordering concrete for floor placement, you should order how much more than the measured volume for small orders?
• Premature drying of concrete after finishing commonly leads to which type of cracking?
• Magnesium bull floats are recommended for use on ___________ concrete and ___________ concrete.
• Which statement about movement at isolation joints is true?
• Direct chute placement from the truck into the forms is usually the easiest and most economical method when which condition is met?
• When concrete is setting slowly, floating should be performed as late as possible, when the finisher's footprint is barely perceptible.
• True or False: Vibrating sticky concrete should be avoided because it tends to bring excessive fines to the surface.
• Floating and troweling too soon is likely to cause which pair of defects?
• Which condition would be least likely to reduce color variation?
• True or False: Vibrating screeds should be moved forward as fast as proper consolidation allows to avoid bringing too much mortar to the surface.
• F(l) numbers indicate levelness or tilt.
• Removing bleed water by dragging a heavy rubber hose across the slab, or with a squeegee should be done only when water, not _______ is removed.
• If a crew can place and finish 100 yd^3 per hour, the producer's rate should be about how many yd^3 per hour?
• Strength of normal weight concrete depends mainly on which factor?
• For floors with high flatness requirements, which tool is preferred over a bull float?
• Bull floats are used after screeding when the specified F-number floor flatness is ____ or less.
• Isolation joint material must be:
• The absence of which condition when joints are wet-sawed indicates the concrete has reached the strength needed to prevent damage from freezing?
• Dusting of the surface in cold-weather concrete placed in a heated enclosure is associated with which process?
• True or False: Typically four float passes and four or more trowel passes are used to produce the desired final finish for a floor.
• When the temperature is above 40 degrees F (4 C), continuous moist curing should be maintained for how many days unless specifications direct otherwise?
• True or False: Reinforcing steel should be located at or above mid-depth of slabs-on-ground so cracks will remain tightly closed at the surface.
• Highway straight edges are used in cutting and filling concrete surfaces at either ______ ________ or ____ degrees to the construction joint.
• Direct chute placement from the ready-mix truck into the forms is usually the easiest and most economical placing method, but may not be possible when:
• What is the standard measurement used for the maximum coarse aggregate size in slabs on ground given as 19 to 38 mm?
• Color differences on a slab finished in different ways are commonly attributed to differences in finishing method.
• You can tell when water was added to the concrete truck by looking at the batch ticket.
• True or False: Concrete is sold by the ton.
• What waste factor is applied in the example problems?
• When used to cure concrete, clear plastic sheets:
• On slabs with many protruding pipes, a ______ works better than a ______ for smoothing the surface.
• Curing by ponding water on the surface is practical only for slabs without joints and where dams can be built to prevent flooding of the base course.
• In hot weather, slab curing may have to start after placing but before finishing. What two methods can be used for this?
• Which statement best describes the relationship between air-entrained concrete and finishing passes in relation to delaminations?
• On stiffer concrete, a forward-turn, forward-pass combination on a rider allows the finisher to always ______ the concrete being floated or troweled.
• An admixture that reduces bleeding while retarding setting will aggravate crusting problems. True or False?
• Bull floating is done:
• Load transfer at construction joints can be provided by smooth dowels or other load transfer devices.
• The F-number system measures what?
• A ___ in diameter pan is the largest size commonly used on walk-behind machines because the finisher can guide the machine more easily than with larger pans.
• Which practice is recommended to minimize plastic shrinkage cracking?
• Increasing the amount of sand in a concrete usually decreases the amount of water needed to make the concrete workable.
• True or False: To improve load transfer at construction joints, plate, round, or square dowels have been used.
• True or False: Pan floats used on either walk-behind or riding machines improve levelness but not flatness.
• Plate dowels in plastic sleeves and square dowels cushioned on the vertical sides by a compressible material permit movement in which directions relative to the construction joint?
• Some ways of minimizing plastic shrinkage cracking include dampening the subgrade and forms without leaving puddles of water; spraying evaporation retarders on the surface immediately after screeding; and using fog sprayers to increase the relative humidity above the slab surface.
• Where a temporary screed is moved, two different placements are sometimes made adjacent to each other. When concrete is softer on one side of the screed's former location, the walk-behind machine should be run _________ to the seam where the two concretes come together, with the blades overlapping the seam by about ____ to ____ inches.
• Which analysis best describes delaminations in terms of depth and formation?
• If a 10% waste factor is applied, how does the required order quantity compare to the exact slab volume?
• To determine if concrete, in place, has the strength needed to put it into service, test cylinders should be:
• Delaminations are caused by a separation between the surface layer and underlying concrete, with depth that may be as much as:
• During protection from freezing, corners and edges are most likely to be damaged by early freezing, so blankets should cover them.
• What is the function of fog sprays in hot-weather curing?
• Sand for concrete used in slabs on ground is easier to finish when it has close to the largest allowable amount of material passing which sieves?
• Hand-held vibrating screeds are often useful when striking off concrete with what type of screeds?
• If rain begins on a newly placed concrete slab, what is the recommended action?
• Which type of screed is used with hand-held vibrating devices to strike off concrete effectively?
• Which statement about curing and drying is true?
• Hard edge forms spaced how far apart to achieve the highest quality levelness?
• Do 24-inch (610-mm) No. 3 or No. 4 reinforcing bars at reentrant corners prevent cracking?
• Keyed construction joints are not recommended for slabs subject to heavy wheel traffic or for slabs less than how many inches thick?
• If contraction joints are sawed too soon with a wet-cut saw, the edges of the joint may _____.
• Which factor is specifically listed as helping to reduce color variation in floors?
• Some float pans have a bottom profile that varies from flat to slightly curved upward. When curved pans are used on walk-behind finishing machines,
• Bull floating should be performed before bleed water comes to the surface.
• True or False: Highway straightedges are used instead of bull floats when high F(f) numbers for floors are specified.
• Oversanded concrete mixtures are likely to produce floors with poor wear resistance and excessive shrinkage.
• What property must isolation joint material possess?
• Slow setting may be caused by which of the following conditions?
• Who should read and understand project specifications to ensure proper execution of a concrete flatwork project?
• True or False: When the concrete truck chutes won't reach the forms, the concrete supplier must approve adding more chutes supported off the truck.
• Which placing sequence for slabs-on-ground is NOT recommended?
• Joints that separate slabs from walls and columns are called ________ joints.
• Concrete from a ready mix truck must be completely discharged within how many hours after water has been added at the plant?
• The gap under the straightedge should be measured at which location?
• Early-entry dry-cut sawing can reduce the waiting period to as little as how many hours in hot weather?
• Which pair of sieve sizes is commonly used to describe the fineness of sand in concrete used for slabs on ground?
• To reduce setting time and increase early strength gain during cold weather, which option is commonly recommended?
• If concrete at the edges is low during machine floating, a __________ pass with the float blades or pan over the ______ will bring more concrete to the edges.
• It is true that when some areas of a floor are setting slower than others, you should work around the slower areas to avoid sealing the surface too soon.
• Which term describes joints that separate slabs from walls and columns?
• What is the recommended action if rain starts on a freshly placed slab?
• True or False: When edging, start at the corner of the slab and apply maximum pressure to ensure that corners will not chip or spall.
• Which statement best describes machine finishing directions?
• Groovers are used primarily to cut grooves to a depth of ______ of the slab thickness for contraction joints in exterior concrete.
• To move left with a walk-behind troweling machine:
• Which factor has the greatest effect on floor levelness?
• To minimize chances of surface blisters forming during floor finishing, which practice is recommended?
• Earth ramps may be built to avoid ________ of the curbs, sidewalks, or driveways.
• Calcium chloride added to concrete acts as an anti-freeze that lowers the freezing point of the concrete very much.
• Plastic shrinkage cracks occur when the slab surface dries faster than the bleedwater rises to the surface. Which of the following best defines plastic shrinkage cracks?
• If some areas of a floor set slower than others, finishing around the slower areas is recommended to avoid sealing the surface too soon.
• Leaving a small unfloated section and waiting for bleed water helps determine if the magnesium bull float is what?
• If blisters form, which step is recommended for surface repair before further finishing?
• Regarding vibration of sticky concrete, which statement is accurate?
• A floor with an Ff number of 40 is twice as flat as a floor with an Ff number of 20.
• Which environmental condition should be maintained to aid color uniformity in concrete floors?
• The direction of the first machine floating pass should be __________ to the direction of the last finishing procedure.
• A 3-in slump concrete that sets very fast will result in?
• Concrete curing refers to keeping the concrete moist and at a high enough temperature for cement to hydrate fast enough.
• Which tool is used after floating to achieve the final surface finish in hand finishing?
• True or False: When concrete will be placed directly on a vapor retarder, finishers should punch holes in the vapor retarder to speed finishing.
• True or False: Power trowels can be used for floating or troweling.
• What is the primary purpose of F-number testing?
• To minimize delays when using a boom pump to place concrete for a slab on ground, you should:
• 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.
• Edgers are used to make neat, ______ edges primarily on ______ concrete.
• Why are floor flatness measurements taken after 72 hours not the best indicator of finishers' skill?
• Manual or motorized buggies can be used to transport concrete from the truck mixer to the point of deposit, but a temporary ________ ________ is usually needed to prevent the buggies from riding directly on any reinforcing bars.
• True or False: Reinforcing steel in slabs on ground does not prevent cracking.
• Before edging, which technique is used to loosen concrete from the side form?
• Granular subbases for slabs on ground can be compacted with which type of roller?
• What finishing practice is most associated with reducing surface scaling on exterior slabs?
• Which type of joints are stopping places for a day's work?
• Which additive is used to slow surface evaporation and help prevent early plastic shrinkage during finishing?
• Hard edge form spacing of 3 to 6 meters is recommended to achieve which of the following?
• Changes in concrete temperature affect which properties?
• Which finishing tool is used to trowel sidewalks that do not require a hard-trowel finish?
• True or False: If concrete loads for a large order are delivered on different days but use the same materials and proportions, there will be no color variations.
• Concrete kept at a temperature of 50 degrees Fahrenheit for one day will usually reach what compressive strength to prevent damage from freezing?
• When placing highway straight edges relative to the construction joint, they should be set at which orientations?
• Which of the following sequences is listed as recommended for casting slabs-on-ground?
• What is the typical effect of finishing in only one direction compared to two directions?