Test
Pop
Este test tiene tipos de pregunta que se abren en el reproductor de siempre.
Preguntas del test (91)
1It is important that the [blank_start]finisher foreman[blank_end] read and understand project specifications
- Afinisher foreman
2If the crew can place and finish 100yd^3 (m^3) of concrete per hour, the producer’s delivery rate should be about [blank_start]100[blank_end] yd^3 (m^3) per hour
- A100
3Concrete is sold by the ton.
- AVerdadero
- BFalso
41a (inch/pound). For a concrete floor slab that is 6in thick, 200ft long and 100ft long wide you should order [blank_start]407[blank_end] yd^3.
- A407
52b(metric). For a concrete floor slab that is 159 mm. Thick, 60m long and 30m. Wide you should order [blank_start]297[blank_end] m^3 of concrete, assuming a 10% waste factor
- A297
6When there is room for two concrete trucks ready to discharge into a pump hopper, placement is faster because:
- ABoth trucks must be discharging at the same time to keep the hopper full
- BAs one truck is finishing the other is ready to unload concrete
- COne driver can discharge both trucks at the same time
- DThe pump operator can discharge both trucks so drivers can take a break
7Concrete from a ready mix truck must usually be completely discharged within [blank_start]1 1/2[blank_end] hours after the water has been added at the plant
- A1 1/2
8You can tell water has been added to the concrete by looking at the:
- ABatch ticket
- BRevolution counter on truck
- CTruck number
- DTime the concrete was ordered
9When concrete for a slab placement will be discharged from the truck chute, truck arrivals should usually be about
- A5min
- B15min
- C45min
- D90min
10When finishers get behind because the concrete is setting faster than expected and the placing crew is also short handed one solution is slowing the concrete delivery rate to match worker output. True or false?
- AVerdadero
- BFalso
11In deciding how much concrete to order for a floor placement you should calculate the number of cubic yards (cubic meters) needed to fill the forms, then order two to three cubic yards (cubic meters) less so you don’t waste concrete that is not needed. True or false?
- AVerdadero
- BFalso
12The question “what finishers or finishers can request addition of water to the concrete ?” truck on site should be answered at the [blank_start]preconstruction meeting[blank_end]
- Apreconstruction meeting
13Concrete made with Portland cement will set and harden while under water
- AVerdadero
- BFalso
14If a concrete slab on ground won’t be exposed to sulfates the cement used is most likely to be:
- AType 1
- BType ll
- CType lll
- DType IV
15Fly ash may be added to concrete from a fly ash silo at the Batch plant or from a silo containing a [blank_start]blended[blank_end] cement
- Ablended
16Most concrete used in slabs on ground has coarse aggregate with a maximum size of:
- A3/8 to 1/2in (9.5 to 13mm)
- B1/2 to 3/4in (13 to 19mm)
- C3/4 to 1 1/2in (19 to 38mm)
- D1 to 2in (25 to 50mm)
17Sand for concrete used in slabs on ground is easier to finish when it has close to the largest allowable amount of material passing the No.50 and No.100 sieves
- AVerdadero
- BFalso
18Increasing the amount of sand in a concrete usually decreases the amount of water needed to make the concrete workable
- AVerdadero
- BFalso
19All concrete that will be subject to freezing when moist or be exposed to deicing salts should contain
- AAn accelerating admixture
- BAir-entraining agent
- CCalcium chloride
- DWater-cement ratio
20Strength of normal weight concrete depends mainly on
- AStrength of aggregate
- BMixing time
- CPurity of the mixing water
- DWater-cement ratio
21Oversanded concrete mixtures are likely to produce floors with poor wear resistance and excessive shrinkage
- AVerdadero
- BFalso
22To minimize shrinkage and reduce cracking and curling
- AUse as much coarse aggregate as possible
- BUse little as mixing water as possible
- CUse aggregates with low shrinkage
- DAll of the above
23Changes in concrete slump most often represent changes in the amount of [blank_start]water[blank_end] in the mixture
- Awater
24Air-entrained concrete is not recommend for use in concrete slabs
- AExposed to freezing and thawing
- BExposed by deicing chemicals
- CFinished by repeated steel troweling passes
- DFinished by bullfloating and brooming
25Changes in concrete temperature affect
- ASetting time
- BAir content
- CSlump
- DAll of the above
26To determine if concrete is in place has the strength needed to put into service , test cylinders should be
- AStored for no more then 48 hours in a moist environment at a temperature of 60 to 80•F (16 to 27•C) then stored at 73•F (23•C) until they are tested
- BStored in water at 73•F (23•C) immediately after casting and tested before putting the concrete into service
- CStored into a temperature controlled job trailer
- DKept at the job site and cured under conditions similar to the curing conditions for the concrete they present
27Granular subbases for slabs on ground can be compacted with sheeps foot rollers
- AVerdadero
- BFalso
28In cold weather the subgrade soil must be free of [blank_start]frost[blank_end] before concrete placing begins
- Afrost
29Before 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 and the surface is soft
- AVerdadero
- BFalso
30Before concreting workers should check the elevation of the subbase by
- AMeasuring down from a straightedge spanning between the side forms
- BMeasuring the distance from the subbase surface to the top of both sets aside forms at 5ft (1.5m) intervals
- CUsing a surveyors level to measure the subbase elevation at the beginning and at the end of the placement
- DCalculating the average elevation of the highest and lowest spots on the subbase surface and comparing that with design elevation
31If the surface of the subbase for a concrete slab on the ground is too low the slab is likely to thin
- AVerdadero
- BFalso
32Which of the following placing sequences for casting slabs on ground is not recommended
- AAdjacent lanes
- BAlternate lanes
- CCheckerboard
33Which of the following have the greatest effect on the floor level ness
- ACompact of the subgrade and base
- BConcrete slump
- CFrom setting and screeding
- DHand troweling slab edges
34When concrete will be placed directly on a vapor retarder finishers should use a margin trowel to punch holes in the vapor retarder and this decrease waiting time before the concrete can be finished
- AVerdadero
- BFalso
35When specifications don’t require a concrete slab to be in direct contact with a vapor retarder the preferred method for reducing potential problems caused by slab curling
- APlacing a 3in (75mm) thick layer of uncompactible concrete sand on the vapor retarder before concrete placement
- BPlacing a 3in (75mm) thick layer of compactible manufactured sand on the vapor retarder before concrete placement
- CPlacing a 2in (51mm) thick layer of lean concrete on the vapor retarder before slab placement
- DPlacing a 3in (75 mm) thick layer of the fly ash or the vapor retarder before concrete placement
36instructions on drawing for slabs on ground may require that:
- Apreventing slab cracking
- Bkeeping any slab cracks tightly closed
- Cpreventing plastic shrinkage cracking
- Dproviding tensile strength at the bottom of the slab
37instrcutions on drawings for slab on ground may require
- Areinforcing steel be discontinoued (cut) so it doesnt pass through the joint
- Bevery other bar or wire be doscontinued (cut) so only half the steel passes through the joint
- Creinforcing steel area be doubled to reduce joint width
- Deither A or B above
38reinforcing steel should be located at or above mid-depth of slabs on ground so cracks will remain tightly closed at the surface:
- AVerdadero
- BFalso
39load transfers at construction joints can be provided by smooth [blank_start]steel dowels[blank_end] or other types of load transfer devices
- Asteel dowels
40keyed constrcution joints are not recommended for slabs subject to heavy wheel traffic or for slabs less than [blank_start]6[blank_end] in thick
- A6
41measuring the gap under a 10ft gap under 1 10ft starightedge is one way of determining
- Afloor flatness
- Bfloor levelness
- Cfloor flatness and levelness
- Dfloor flatness and levelness f-numbers
42the f-number system is one way of determining
- Afloor flatness
- Bfloor levelness
- Cfloor flatness and levelness
- Dpossibility of a floor covering faliure
43F (f) numbers are indicators of floor surface smoothness or flatness
- AVerdadero
- BFalso
44F (L) numbers are indicators of levelness or tilt of the floor surface
- AVerdadero
- BFalso
45which of the following finishing operations affect floor flatness
- Afloating
- Brestraightening
- Ctroweling
- Dall of the above
46a 3.5 in (75mm) slump concrete that sets very fast is most likely to result in :
- Alittle finishing effort needed to get a high FF number floor
- Ba lot of finishing effort needed to get a high FF number floor
- Ca floor surface with craze cracks
- Da floor with high abrasion reiststance
47f number should preferably be done within [blank_start]24[blank_end] hours after concrete placement but never later than [blank_start]72[blank_end] hours after concrete placment
- A72
- B24
- C24
- D72
48a floor with an F (f) number of 40 is twice as flat as a floor with an F (f) number of 20
- AVerdadero
- BFalso
49floor flatness measurements taken more than 72 hours after concrete placement are the best measure of the finishers skills
- AVerdadero
- BFalso
50the highest quality of levelness can be achieved by using hard edge forms spaced
- A10-20ft (3-6m) apart
- B15-30 ft (4.9 to 9 meters) apart
- C20 to 40 ft ( 6 to 12m) apart
- Dat least 50 feet (15 m) apart
51if the ready mix truck can be drivern into the slab placement area, chuting concrete directly into the forms is usually the easiest and most economical placing method , this may not be possible when:
- Athe trucks must drive over side walks, curbs , or rive ways
- Bslab reinforcing bars are supported by chairs
- Ctruck tiers leave deep ruts in the subgrade or grancular base
- Dany of the above
52although placing concrete directly from the truck is economical , getting the truck to the discharge point may require driving it over curbs or on sidewalks . to avoid [blank_start]cracks[blank_end] on the curbs, sidewalks or the driveways, earth ramps may need to be built
- Acracks
53when guiding a coincrete truck near 6 ft deep excavation the truck wheels closest to the excavation should be [blank_start]6[blank_end] ft or more away from the edge of the excavation
- A6
54when the concrete truck chutes wont reach the forms, the concrete supplier must approve adding more chutes off the truck
- AVerdadero
- BFalso
55manual or monitorized buggies can be used to transport concrete from the truck mixer to the point of deposit but a temporary [blank_start]plywood ramp[blank_end] is usually needed to prevent the buggies from riding directly on any reinforcing bars
- Aplywood ramp
56when concrete is placed by crane and bucket, buckets must never be filled over [blank_start]personal[blank_end] or over [blank_start]travel[blank_end] paths
- Apersonal
- Btravel
57truck mounted conveyors are especially useful on jobs with [blank_start]height restrictions[blank_end] such as warehouse slabs when the building is enclosed prior to placement
- Aheight restrictions
58one disadvantage of using trailer pumps for slab on ground placements is
- Amost trailer pumps cant deliver concrete as fast as it can be placed and finished
- Bdelayed are caused by removing heavy pipelines sections as the placement progresses
- Cslab-on-grade concrete is so stiff that pump blockages are common
- Dfor most effiecent operation , trailer pmps must move concrete through 1200ft of horizontal pipeline
59when boom pumps are used to place concrete two important equpment features are [blank_start]boom[blank_end] reach and delivery [blank_start]output[blank_end]
- Aoutput
- Bboom
60when using a boom pump to place concrete for a slab on ground you can minimize delays by
- Amaking sure the boom length is equal to the farthest distance that concretes must be pumped
- Ballowing enough space near the boom so as one truck is finishing the other is ready to unload concrte
- Cmoving the pump to three or more locations during the placement so the boom is never fully extended
- Dplacing the boom oump as close as possible to the powerline so power is avialable for operating vibrators and other eletrical equipment
61tools commonly used for hand spreading concreete in slbs include
- Ashort handed square ended shovels
- Bround point shovel
- Cgarden rakes
- Dall of the above
62bull floats are used after screening when the specified F umber floor flatness is [blank_start]F (f) 20[blank_end] or less
- AF (f) 20
63bull floating must be done after all of the bleed water has evaporated from the surface
- AVerdadero
- BFalso
64[blank_start]wood[blank_end] bull floats are less likely to seal the surface
- Awood
65highway starightedeges are used instead of bull floats when high FF numbers for floors are specfied
- AVerdadero
- BFalso
66groovers are primrily used for
- Acut grooves to a depth of 1/4 the slab thickness for contraction joints in exterior concrete
- Bcut grooves to a depth of 1/4 of the slab thickness for the contraction joints in industrial floors
- Ccut grooves for any floor subjected to hard wheeled forklift traffic
- Dcut shallow grooves that serve as decorative contraction joints
67wood hand floats are
- Aare likely to seal the surface of air entrained concrete
- Bare best for non air entrained concrete or high slump concrete
- Cwork better than magnesium floats on sticky concrete
- Dlast longer than magnesium flots
68hand trowlels used for the first troweling should be short and narrow to increase teh pressure on the concrete surface
- AVerdadero
- BFalso
69fresnos are long handled trowels with blades 24 to 48 in long that are used
- Ainstead of bull floats to smooth the concrete surface
- Bbefore bleeding has begun
- Cfor troweling slabs such as sidewalks that do not require a hard trowel finish
- Dso finsihers dont ahve to use knee boards when trowleing industraial floors
70float blades for power troweling machines are much wider than trowel blades and are turned up on the edges to prevent them from digging into the surface
- AVerdadero
- BFalso
71some float pans have a bottom profile that varies from flat to slightly curved upward. when curved pans are used on walk behind finishing machines
- Athe pans edes rise very little during floating
- Bthe surface of rhe flatness increases when compared with flat pans
- Cthe wlak behind machines wear out faster
- Dthe reduced pan to conrete contact cuts drag and eases handeling
72a [blank_start]36[blank_end] in diameter pan is in the largest size commonly used on walk-behind machines because the finisher can guide the machine more easily than with larger pans
- A36
73power trowels can be used for floating or troweling
- AVerdadero
- BFalso
74when one bent or broken blade on a double or triple rotor troweling machine is replaced [blank_start]all[blank_end] blades should be replaced
- Aall
75rigid supports for a straightedge used to strike off concrete can be
- Atemporary pipes or rails
- Bedge forms
- Cthe top of the edge of a adjacent hardende concrete
- Dall of the above
76how many workers avoid low spots when using hand-operated straightedge, make sure there [blank_start]is enough concrete ahead of straightedge[blank_end]
- Ais enough concrete ahead of straightedge
77hand held vibrating screeds are often useful when striking off concrete with [blank_start]wet screeds[blank_end]
- Awet screeds
78vibrating screeds should be moved forwars=ds as fast as proper consiolidation allows to avoid bringing too much mortar to the surface
- AVerdadero
- BFalso
79on slabs with many protruding pipes a [blank_start]darby[blank_end] works better than a [blank_start]bull float[blank_end] for smoothing the surface
- Adarby
- Bbull float
80bull floating is done
- Abefore screeding
- Bimmideatly after screening
- Cimmediatley after bleed water has evaportaed
- Dimediatey after hand floating
81when using a magnesium bull float , leaving a small unfloated section and watching for bleed water in that section can help determine if the magnesium float is [blank_start]sealing[blank_end] the surface
- Asealing
82highway straigh edegs are used in cutting and fillig concrete surfaces at either [blank_start]right angles[blank_end] or [blank_start]45[blank_end] degrees to the construction joint
- Aright angles
- B45
83floating and troweling a concrete slab too soon is likely to cause [blank_start]dusting[blank_end] and [blank_start]crazing[blank_end]
- Adusting
- Bcrazing
84removing bleed water by drgging a heavy rubber hose across the slab or with a squeegee should be done only when water not [blank_start]paste[blank_end] is removed
- Apaste
85edging at side forms is most commonly done on
- Acommerical floor slabs
- Bindustrail floor slabs
- Csidewalks and driveways
- Dall floor slabs
86use a pointed trowel with a vertical sawing motion to loosen concrete from the side from before [blank_start]edging[blank_end]
- Aedging
87an edger is placed [blank_start]flat[blank_end] on the concrete surface and then [blank_start]titled up[blank_end] slightly in the direction the tool is moved
- Atitled up
- Bflat
88when edging, start at the corner of the slab and apply maximum pressure to ensure rtghat the corners will not chip or spall
- AVerdadero
- BFalso
89edging and jointing is not required on most floors and should not be done unless specfied
- AVerdadero
- BFalso
90a fine broom finish
- Ais ocassionally required for interior flat work
- Bfollows immediately after the bull floating pass
- Cis produced by pushing the broom toward the opposite form
- Dis best produced by soaking the broom in water just before it is used
91after the waiting period floating is done to
- Aembed large aggregate particles beneath the surface mortar layer
- Bremove slight humps to produce a plane level surface
- Ccompact alnd further consilidate teh surface in preparation for other finisihing
- Dall of the above
Información
- Descripción
- Test sobre Pop, creado por Carlos Rodriguez el 03/07/2018.
- Autor
- Carlos Rodriguez
- Idioma
- English
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- 0
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