Item 311 Portland Cement Concrete Pavement (PART 1)

78問 • 1年前

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Only _________________ Portland Cement shall be used unless otherwise provided for in the Special Provisions

Type 1

Fine aggregates shall not contain more than _____________ of material passing the 0.075 mm (No. 200 sieve) by washing nor more than _____________ of each of clay lumps or shale

3%, 1%

If the fine aggregate is subjected to five cycles of the sodium sulfate soundness test, the weighted loss shall not exceed _____________

10%

When tested for the effect of organic impurities on the strength of mortar, the fine aggregate may be used if the relative strength at 7 and 28 days is not less than _____________

95%

Coarse aggregates shall not contain more than _____________ of material passing the 0.075 mm (No. 200) sieve, not more than _____________ of clay lumps, nor more than _____________ of soft fragments

1%, 0.25%, 3.5%

If the coarse aggregate is subjected to five cycles of the sodium sulfate soundness test, the weighted loss shall not exceed _____________

12%

Coarse aggregates shall have a mass percent of wear not exceeding _____________ when tested by AASHTO T 96

No. 40

If the slag is used in coarse aggregate, its density shall not be less than _____________

1120 kg/cu.m

Dowels shall be plain round bars, before delivery to the site of work, ____ of the length of each dowel shall be painted with one coat of approved lead or tar paint

1/2

The sleeves for dowel bars shall be metal of approved design to cover ____, plus or minus 5 mm of the dowel

50mm

The sleeves for dowel bars shall have a closed end, and with a suitable stop to hold the end of the sleeve at least ____ from the end of the dowel

25mm

The diameter of wire for lateral and longitudinal directions shall not be less than ____ in diameter

6mm

The spacing on the lateral direction is _____ wider than that of the longitudinal direction

twice

The weight of the wire mesh shall not be less than ____.

3 kg/sq.m

In an installation of wire mesh, a slip bar shall be placed at every _____ maximum interval. Cotton mats and waterproof paper can be used for weakened plane joints

Wire mesh shall be placed at a depth of ___________ below the surface of the slab or at 2/3 of the thickness from the bottom of the pavement

5cm to 7.5cm

Admixtures can be Fly Ash if specified or permitted as a mineral admixture and not exceeding ____ partial replacement of Portland Cement in the concrete mix

20%

Storage buildings shall have the capacity for storage of a sufficient quantity of cement to allow sampling at least ___ days before the cement is to be used

In order to secure greater uniformity of the concrete mix, the Engineer may require that the coarse aggregate be separated into ___ or more sizes

To meet the minimum strength requirements, at least _____ of cement per cubic meter of concrete is required

364 kg

If not vibrated, the cement content and the proportions of aggregate and water will produce workable concrete having a slump of between __________.

40mm and 75mm

If vibrated, the cement content and the proportions of aggregate and water will produce workable concrete having a slump of between:

10mm and 40mm

The Engineer shall determine from laboratory tests of the materials to be used, the cement content and the proportions of aggregate and water that will produce workable concrete having a flexural strength of not less than ____ when tested by the third-point method.

3.8 MPa

4.5 MPa

A compressive strength of 24.1 MPa for cores was taken at _____ and tested in accordance with AASHTO T 24

14 days

The designer shall consider the use of lean concrete (econocrete) mixtures using local materials or specifically modified conventional concrete mixes in the base course and the lower course composite, monolithic concrete pavements using a minimum of _____ of conventional concrete as the surface course

75mm

Scales for weighing aggregates and cement shall be of either the beam type or the springless-dial type, they shall be accurate within ____ throughout the range of use

0.5%

The mixer shall be equipped with an approved timing device which will automatically lock the discharge lever when the drum has been charged and release it at the end of the mixing period. In case of failure of the timing device, the mixer may be used for the balance of the day while it is being repaired, provided that each batch is mixed for:

90 seconds

The concrete shall be placed with an approved paver designed to spread, consolidate, screed and float finish the freshly placed concrete in __________ of the machine in such a manner that a minimum of hand finishing will be necessary to provide a dense and homogeneous pavement in conformance with the Plans and Specifications

1 complete pass

The finishing machine shall be equipped with at least ___ oscillating type transverse screed

Vibrators shall operate at a frequency of __________ impulses per minute under load at a maximum spacing of ______.

8300 to 9600, 60cm

Contractor shall provide at least ___ stand-by saw in good working condition and with an ample supply of saw blades

The flange braces must extend outward on the base to not less than ___ the height of the form

2/3

The areas which will support the paving machine and the grade on which the pavement is to be constructed shall be trimmed to the proper elevation by means of a properly designed machine extending the prepared work areas compacted at least ____ beyond each edge of the proposed concrete pavement

60cm

Any roadbed, which at the form line is found below established grade, shall be filled with approved granular materials to grade in lifts of ____ or less, and thoroughly rerolled or tampered

3cm

After the forms have been set to correct grade, the forms shall not deviate from the true line by more than ___ at any point

1cm

Stockpiles shall be built up in layers of not more than ___ in thickness

All washed aggregates and aggregates produced or handled by hydraulic methods shall be stockpiled or binned for draining at least ______ before being batched

12 hours

When cement is placed in contact with the aggregates, batches may be rejected unless mixed within ______ of such contact

90 minutes

Batching shall be so conducted as to result in the weight of each material required within a tolerance of ___ for aggregates and ___ for the cement

1%, 2%

Water may be measured either by volume, or by:

weight

The accuracy of measuring the water shall be within a range of error of not more than:

When mixed at the site or in a central mixing plant, the mixing time shall not be less than ___ seconds nor more than ___ seconds for drum-type mixers, unless mixer performance tests prove adequate mixing of the concrete in shorter time period

50, 90

An overload up to ___ above the mixer's nominal capacity may be permitted provided concrete test data for strength, segregation, and uniform consistency are satisfactory, and provided no spillage of concrete takes place

10%

The flow of water shall be uniform and all water shall be in the drum by the end of the first _____ of the mixing period

15 seconds

The time elapsed from the time water is added to the mix until the concrete is deposited in place at the site shall not exceed ___ minutes when the concrete is hauled in non-agitating trucks

The time elapsed from the time water is added to the mix until the concrete is deposited in place at the site shall not exceed ___ minutes when hauled in truck mixers or truck agitators, except in hot weather or under other

In exceptional cases and when volumetric measurements are authorized for small projects requiring less than ___ cu.m. of concrete per day of pouring, the weight proportions shall be converted to equivalent volumetric proportions

Retempering concrete by adding water or by other means shall not be permitted, except that when concrete is delivered in truck mixers, additional water may be added to the batch materials and additional mixing performed to increase the slump to meet the specified requirements, if permitted by the Engineer, provided all these operations are performed within ___ minutes after the initial mixing operation and the water-cement ratio is not exceeded

During hot weather, the Engineer shall require that steps be taken to prevent the temperature of mixed concrete from exceeding a maximum temperature of ___°C

Concrete not in place within ___ minutes from the time the ingredients were charged into the mixing drum or that has developed initial set shall not be used

If only finishing equipment is carried on the existing lane, paving in adjoining lanes may be permitted after ___ days

In no case shall the vibrator be operated longer than ___ seconds in any one location

As work progresses, at least one set consisting of concrete beam test specimens, ___ mm x ___ mm x ___mm, shall be taken from each ___ m² of pavement, ___ mm depth, or fraction thereof placed each day

150, 150, 525, 330, 230

When reinforced concrete pavement is placed in ___ layers, the bottom layer shall be struck off and consolidated to such length and depth that the sheet of fabric or bar mat may be laid full length on the concrete in its final position without further manipulation

Any portion of the bottom layer of concrete which has been placed more than ___ minutes without being covered with the top layer shall be removed and replaced with freshly mixed concrete at the Contractor's expense

The longitudinal joints shall be:

continuous

The expansion joint filler shall be held in a ______ position

vertical

Finished joint shall not deviate more than _____ from a straight line.

6mm

The depth of the weakened plane joint should at all times not be less than ____

50mm

The width of the weakened plane joint should at all times not be more than _____

6mm

Sawing of the joint shall commence as soon as the concrete has hardened sufficiently to permit sawing without excessive raveling, usually ______

4 to 24 hours

Transverse Construction Joint shall be constructed when there is an interruption of more than ______ in the concreting operations

30 minutes

No transverse joint shall be constructed within ____ of an expansion joint, contraction joint, or plane of weakness

1.5m

If sufficient concrete has been mixed at the time of interruption to form a slab of at least ___ long, the excess concrete from the last preceding joint shall be removed and disposed of as directed

1.5m

The sleeves for dowels shall be metal designed to cover ____, plus or minus 5 mm, of the dowel

50mm

The sleeves for dowels shall have a watertight closed end and a suitable stop to hold the end of the sleeves at least ____ from the end of the dowel

25mm

The finishing machine shall be stopped when the front screed is approximately ____ from the joint

20cm

The screed for the surface shall be at least ____ longer than the maximum width of the slab to be struck off

60cm

The hand-operated longitudinal float shall be not less than _____ in length

365cm

The hand-operated longitudinal float shall be not less than _____ in width

15cm

Movement ahead along the center line of the pavement shall be in successive advances of not more than ___ the length of the float

1/2

The float shall pass over each areas of pavement at least ______, but excessive operation over a given area will not be permitted

2 times

The rigid frame shall be carried by ___ or more visible wheels riding on, and constantly in contact with the side forms

Long handled floats having blades not less than _____ in length and ____ in width may be used to smooth and fill in open-textured areas in the pavement

150cm, 15cm

After floating, any excess water and laitance shall be removed from the surface of the pavement by a:

3m straight edge

Successive drags shall be lapped ___ the length of the blade

1/2

While the concrete is still plastic, the surface of the concrete shall be tested for trueness with a:

300cm straight edge

Project Engineer EXAM

Vaantoote · 62問 · 2年前

Project Engineer EXAM