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152 Cards in this Set
- Front
- Back
Before placing concrete you should inspect all supporting members because wet concrete will always exert what type of pressure on them? |
Hydrostatic |
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Nailing requirements must comply with what directive? |
Specs and plans |
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When should supervisor inspect all forms? |
Before each placement |
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When working with concrete personnel should wear gloves and protective goggles and have their sleeves rolled down to prevent what hazardous results? |
Cement poisoning |
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When working with concrete personal should stand with their backs to the wind to prevent what? |
Debris flying into their eyes |
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What term is used to refer to a temporary structure that can support its own weight and that of freshly placed concrete as well as the wake of materials workmen and equipment and equipment imposed upon it? |
Formwork |
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As a supervisor of the form building crew you should consider what factors as your principal objectives? |
Economy quality and safety |
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Formwork may represent as much as what percentage of the cost of a concrete structure? |
33% |
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Concerning formwork and what areas will good judgment and ingenuity on the part of the supervisor help reduce cost? |
Materials planning and scheduling |
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Forms must be designed to meet what weight factor? |
Total weight to which they may be subjected |
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What are the most commonly used types of form material? |
Earth metal lumber plywood and fiber |
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The majority of all formwork involves concrete. concrete weighs a total of how many pounds per cubic foot? |
150 pounds per cubic foot |
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For each inch slab thickness concrete slabs place a total load of how many pounds per cubic foot on the formwork? |
12.5 pounds per square foot |
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In pounds per square foot of horizontal direction what is the minimum recommended construction live load provisions for the weight of the crew members and equipment? |
50 pounds per square foot |
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When powered concrete buggies are used in concrete operations what is the minimum construction live loads recommended for use in PSF? |
75 PSF |
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What bracing technique is most often used to brace forms against lateral pressure? |
Diagonal and horizontal members |
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What factors have an effect on lateral pressure? |
Consistency amount vibration size of aggregate and placing procedures |
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To determine the uniform load of a stud you multiply the maximum concrete pressure by the minimum stud spacing. Then dividing the results by 12 you convert the answer into what unit of measure? |
Pounds per linear foot |
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By dividing the height of the form by the rate for placement will give me what? |
The time required to place concrete |
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Braces are used against wall forms to protect from mishaps due to external forces. The value of the external force is estimated to be how many times the wall height in feet? |
12.5 |
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Designing wall forms and the bracing of them should be the responsibility of what person? |
Project engineer |
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What is the first step in designing what forms for a concrete columns? |
Determine the materials |
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In which of the following forms may reinforce steel be used? |
Bars or rods |
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To calculate manpower estimates you must first estimate what factor? |
Square footage of concrete surface |
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Reinforced concrete refers to concrete containing steel to reinforce and absorb what type of stress? |
Tinsel and shearing |
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Reinforcing bars are hot rolled From steel recovering from which the following sources? |
Steel billets and rail road car axles and railroad rails |
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When mixed properly a good uniform batch of concrete should pass for maximum values in what? |
Durability and economic and strength |
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What type of mixture is considered the simplest form of concrete batching? |
1.2.4 carpenters mix |
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When very rich mix is needed because of great strength is required you should use what mix design? |
1.1.2 mix |
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What type of mix do you use in large slabs and walls? |
1.2.5 medium mix |
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When a lean mix is needed because you use it in large foundation or as a back information you should use what mix design? |
1.3.5 mix |
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When a very lean mix is needed to only in mass placing it is to be done you should use what makes design? |
1.4.8 mix |
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You can use one of which of the following message to achieve more control over the proportional quantities of the cement water and aggregate for a concrete mix? |
Book and trial batch and absolute value |
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Construction crews in the field must convert the design trial mix or change into field mix for portions by adjusting the mix for what? |
Moisture and entrained air |
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What are added to concrete mortar or grout immediately after mixing? |
Add mixtures |
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What admixture is most commonly used in concrete mixers? |
Air entrained agent |
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THe primary reason for using an air entrained agent in a concrete mix is to improve what property of the concrete? |
Resistance to freezing and thawing exposure |
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When sampling for a strength test you should get a sample of not less than how many cubic feet? |
One cubic foot |
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Samples taken from evolving drum truck mixers must be taken at a minimum of how many intervals? |
Three intervals |
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In obtaining a sample of concrete from my paving mixer sure they should be collected from at least how many proportions of the pile? |
Five intervals |
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You must take a sample to another location to conduct a compressive strength test the time lapse between taking in molding the sample cannot exceed how many minutes? |
15 minutes |
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With how many strokes should you rod each layer of concrete placed in the compressive strength test mold? |
25 times |
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The flexural strength of concrete is it's ability to resist what? |
A braking force |
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What are case and either metal or heavy cardboard molds? |
Test cylinders |
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A total of how many layers of concrete should you place in the mold when prepping a compressive strength test specimen? |
Three layers |
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To calculate the number of cubic yards required for a pad divide the cubic feet of the pad by what number? |
27 |
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Most concrete specifications required that the batching be performed by what? |
Weight |
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How many rotations of the drum of a transit mixture of mixing to be a required to provide concrete of the specified uniformity? |
70 to 100 |
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What are some examples of precast concrete structures? |
Highway girders and poles |
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You should not continue to operate a mobile concrete mixer plant if the hydraulic oil temperature exceeds what temperature? |
190° |
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What type of panel consist of two thin dense reinforced concrete faced slabs separated by a core of insulating material |
Sandwich |
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Post tensioning is used in what unit weighs over seven 7 tons or over how many feet long? |
45 feet |
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Conventional concrete weighs approximate how many pounds per cubic foot? |
150 pounds per cubic foot |
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Depending on its intended use the weight of lightweight concrete falls within what range in pounds per cubic foot? |
90 to 120 |
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Heavyweight concrete as a density of up to how many pounds per cubic foot? |
400 |
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Semi lightweight concrete has a unit weight of how many pounds per cubic foot? |
115 to 130 |
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Insulating lightweight concrete has a unit weight of how many pounds per cubic foot? And a compressive strength seldom exceed what in psi? |
15 to 90 1000 psi |
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Structural lightweight concrete has a unit weight of how many pounds per cubic foot? And with a 28 day compressive strength in excess of what in psi? |
85 to 115 2500 psi |
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What type of construction is a special form of precast concrete building? |
Tilt up concrete |
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When building casting services for precast concrete panels you should use 3000 PSI or higher reinforced concrete and ensure the slabs are at least how thick in inches? |
6 inches |
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What material is most often used for edge forms? |
Two by lumber |
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Bond breaking agents are classified into what two types? |
Sheet materials and liquids |
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A good bond breaking agent can be made by mixing 5 pounds of paraffin with how many gallons of kerosene? |
One and a half gallons |
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When WWF is used what else is needed between the columns and panels? |
Dowels or bars |
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To achieve proper strength cast panels must be cured how? |
Just like any other concrete |
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At the job site what type of lifting attachments can be made for rebar? |
Hairpins |
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At the job site what type of lifting attachments can be made for rebar? |
Hairpins |
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Concrete has a low ability to resist from what? |
Stretching, bending and twisting |
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What principal factor controls the strength of a concrete? |
Water cement ratio |
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The major factor controlling the durability of concrete is what? |
Strength |
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If more water is added to a concrete mix than is needed to hydrate the cement the concrete becomes less what? |
Watertight |
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The production of good concrete is impossible unless good quality materials are used in the mix in this mix is properly what? |
Worked and cured |
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Portland cement is manufactured from finely ground limestone mix with what? |
Clay, shale, or Marl |
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For highway construction type three Portland cement is sometimes preferred to type one because type III has which characteristics? |
Shorter curing time |
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What type of cement was developed for use in areas subject to severe frost and ice conditions? |
Air entrained |
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What material is combined with cement and water to make concrete? |
Aggregate |
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Concrete is denser and stronger and what condition is met? |
All voids are filled |
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When determining the percentage of material restrained on the sIeve of aggregate what type of test is to be done? |
Sieve analysis |
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By building of piles in layers by dumping success of loads along side each other prevents what? |
Aggregate from segregating during stock piling |
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In concrete how is laitance produced? |
Cement is hydrated with excessive water |
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The proportion of air in training agent added to a concrete mixer should fall within what range? |
3 to 7% |
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To slow the rate of hydration what do you use? |
Retarders |
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What is the main reason to store cement in a dry place? |
To prevent it from setting to slowly and producing weak concrete |
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When storing sacks of cement in warehouse what is the main reason to stack them close together? |
To restrict the circulation of air between them |
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Before using warehouse packed cement what should you do to make it lump free? |
Roll the sack around |
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Before using warehouse packed cement what should you do to make it lump free? |
Roll the sack around |
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True or false, in the field mix, the normal gallons of water per Sacco cement must be increased to allow for the saturated surfaced dry conditions of the sand |
False |
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When available aggregate is inch and a half inches what rule of thumb should you use to calculate materials required for a proper concrete mix? |
Rule 42 |
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For each layer of concrete Placed in a mold for a slump test how many time should you rod the mold? |
25 times |
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After completing a concrete slump test you tap the sides of the mix and the concrete crumbled apart what conditions exist? |
Over sanded mix |
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When incorrect concrete slab is detected what action should you take to correct the problem? |
Decrease or increase the aggregate, or change the portions of the fine course aggregate |
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The rated capacity of a concrete mixing machine is determined by what? |
The cubic feet of the mixed concrete |
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In cement batch plant operations the aggregate must pass through what before being discharged into the mixer? |
A weigh boxer |
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In an 11- S concrete mixer what maximum size aggregate can be used? |
3 inch |
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In an 11-S concrete mixture what should water be added to the mix? |
After all the dry ingredients have been added |
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You are to charge the skip Of an 11-S concrete mixture in what order should you add the dry ingredients? |
Aggregate, cement and sand |
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When using a large mixing machine what minimum time should you mix 2-1/3 cubic yards of concrete? |
Two minutes and 15 seconds |
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What is the maximum time you should make sure the inside of the mixing drum is clean? |
One and a half hours |
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When cleaning a mixing drum you should place the course aggregate in the drum and turn hours long? |
Five minutes |
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When concrete must be discharged more than 4 feet above the level of placement why should it be dumped into an elephant trunk? |
To reduce segregation |
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When mixing concrete in a mixing drum the concrete should be dumped no later than how long? |
One and a half hours |
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What type of concrete mix can mix concrete in route to the job site? |
Transit mix truck |
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In building construction what is the most common type of forming material? |
Wood |
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What type of joint should you use to make watertight concrete forms? |
Tongue and groove |
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The hydrostatic head exerted on forms during concrete placing operation normally continue what maximum time? |
One and a half hours |
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Footings for any foundation should always be placed below what? |
The frost line |
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Footings for any foundation should always be placed below what? |
The frost line |
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And exterior wall that serves as an enclosure and also transmit structural loads to the foundation is considered way? |
Load bearing wall |
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Footings for any foundation should always be placed below what? |
The frost line |
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And exterior wall that serves as an enclosure and also transmit structural loads to the foundation is considered way? |
Load bearing wall |
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What term best describes the term keyway in a concrete footer? |
The 2x2 that goes across the forms |
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Horizontal form members that tie pre-fabricated panel together are called what? |
Wailers |
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Horizontal form members that tie pre-fabricated panel together are called what? |
Wailers |
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What are not part of concrete form design and provide no additional strength? |
Braces |
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What type of form tying device is used with cone nuts? |
Tie rods |
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When constructing stair forms you should extend the platform what approximate distance past the sides? |
12 inches |
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You are pouring concrete but a suitable bond preventing compound is not available to prevent the word forms bonding to the concrete what substance is a substitute alternative? |
Water |
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What is the best bond breaking agent to use on still forms? |
Marine engine oil |
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True or false, A light film of rust or mill scale is acceptable on rebar? |
True |
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Which of the rebar ties should you use when A finished Matt, is to be lifted by crane? |
Saddle time with a twist |
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In floor slabs all steel reinforce bars should be separated by what minimum distance? |
1 inch |
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When a column assembly of reinforcing bars is raised in to place the reinforcing steel is tied to the column form at intervals of what? |
5 feet |
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In footing construction what may be used instead of steel supports under reinforcing bars? |
Stones |
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A joint that separates a floor slab from a column is called a what? |
And isolation joint |
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A joint allows the transfer of part of the load from one structural element to another through the use of keys or Dows is called a what? |
Construction joint |
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What type of blade is normally use to cut seasoned concrete or green concrete? |
Diamond or carborundum |
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High-quality concrete requires what? |
A well-designed mix and good placing procedures |
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What is the maximum distance concrete should be dropped from a shoot? |
4 feet |
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What is the best tool for contacting concrete? |
Mechanical vibrator |
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What procedure is used to bring a concrete surface to the required elevation? |
Screeding |
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Speed at which a vibrator screed is pulled across concrete directly depends on what factor? |
The slump of the concrete |
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What finishing tool get a concrete smooth dense finished surface? |
Steel trowel |
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What process produces a non-skid or rough concrete surface? |
Brooming |
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What process produces a non-skid or rough concrete surface? |
Brooming |
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When mortar is being used in rubbing a concrete surface how long should the surface be kept moist you cure? |
1 to 2 days |
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Concrete made with ordinary cement is generally cured for what minimum period? |
Three days |
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When curing flat surfaces what allows the concrete to maintain a uniform temperature? |
Ponding |
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What material is the best insulator? |
Straw |
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When plastic is used in concrete curing process what is the minimum overlap for adjacent sheets? |
12 inches |
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When plastic is used in concrete curing process what is the minimum overlap for adjacent sheets? |
12 inches |
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When patching concrete you should apply mortar in layers not exceeding what maximum thickness? |
Half-inch |
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What surface is best for precast concrete? |
Concrete |
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At what point in concrete casting should the bond breaking agent be applied to a casting surface? |
After the edge forms are placed |
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What is the simplest method for pick up on small cast panels? |
Two point |
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What is the most common type of brace used in till up concrete construction? |
Tubular |
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Because of their flexibility in tendency to stretch what are unstable for most projects? |
Cable braces |
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In cast concrete sand streaking is caused by what? |
Escape of mortar from loose forms |
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Compared to cast in Place panels precast panels have what made advantage? |
Less forming material is required Placing the rebar is easier Through filling and vibrating are easier |
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What type of cement is generally purpose cement for concrete that does not require any special properties of the other types and reaches its design strength in about 28 days? |
Type one |
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What type of cement is modify to resist moderate sulfate attack and reaches its design strength in about 45 days? Which type is sulfate resistant and reaches its design strength in about 60 days? |
Type two Type five |
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What type of cement is high early strength cement that produces design strength at an early age usually seven days or less? |
Type Three |
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What type of cement is a special cement and reaches its design strength in about 90 days? |
Type four |