Mississippi Concrete Examination

Per OSHA 1926.701, what must be done with protruding reinforcing steel onto or into which employees could fall?

• APaint the bars high-visibility orange
• BGuard the bars to eliminate the impalement hazard
• CBend every bar flat before any other trade arrives
• DCover only bars taller than 6 feet

According to OSHA 1926.701, which practice is prohibited during concrete placement with crane-handled buckets?

• ARouting the bucket over the fewest exposed workers practical
• BUsing a bucket with a positive safety latch on a pneumatic gate
• CAllowing an employee to ride the concrete bucket
• DKeeping nonessential workers out from under an elevated bucket

A crane is lowering a loaded concrete bucket into a wall form. Where may employees stand while the bucket is being elevated or lowered into position?

• ADirectly under the bucket to guide it by hand
• BAnywhere inside the form as long as hard hats are worn
• CNot under the bucket; they must stay clear of the load path
• DOn the bucket bail to steady the descent

During post-tensioning, OSHA 1926.701 requires which control?

• AOnly essential employees may be behind the jack, and signs and barriers must limit access
• BAll trades may watch from behind the jack if they wear eye protection
• CThe jack may be operated without barriers if the tendon is less than 50 feet long
• DEmployees may stand in line with the tendon to check elongation by eye

A walk-behind power trowel that is manually guided must, per OSHA 1926.702, have which feature?

• AA lock-on throttle so the operator can use both hands for finishing
• BA control switch that shuts off power when the operator's hands leave the handles
• CA minimum 36-inch handle extension beyond the guard ring
• DAn unguarded blade so the operator can see the pan

A concrete mixer with a 1 cubic yard or larger loading skip must be equipped with which OSHA 1926.702 combination?

• AA mechanical skip-clearing device and guardrails on each side of the skip
• BA spotter only, with no skip guards required
• CA canvas cover over the drum and no skip rails
• DA gravity skip with no mechanical clearer if the operator stands clear

OSHA 1926.702 requires concrete pumping systems that use discharge pipe to have pipe supports designed for what overload?

• A10 percent overload
• B25 percent overload
• C50 percent overload
• D100 percent overload

An employee is applying a cement, sand, and water mixture through a pneumatic hose. What personal protective equipment does OSHA 1926.701 require?

• AHearing protection only
• BProtective head and face equipment
• CA welding hood with a No. 10 filter
• DNo special head or face protection if goggles are in the truck

OSHA 1926.702 requires masonry saws to be guarded with which enclosure?

• AAn open top splash shield only
• BA full plywood box around the operator
• CA semicircular enclosure over the blade that can retain blade fragments
• DNo guard if the saw is used outdoors

Before an employee repairs a concrete mixer where inadvertent startup could cause injury, OSHA 1926.702 requires what energy-control step?

• ATell nearby workers the mixer is down and begin work immediately
• BLock out and tag all potentially hazardous energy sources; tags must read Do Not Start or…
• CRemove only the spark plug on gasoline mixers and leave electric mixers energized
• DPlace a traffic cone on the skip

When may construction loads be placed on a newly cast concrete structure under OSHA 1926.701?

• AAs soon as the surface can take a footprint
• BAfter any laborer says the concrete looks hard
• COnly after a person qualified in structural design provides information that the structur…
• DAfter 4 hours regardless of mix or temperature

OSHA 1926.704 sets which minimum capacity combination for precast lifting?

• ATilt-up inserts 2 times the maximum intended load, other precast inserts 4 times, and lif…
• BAll inserts and hardware 1.5 times the maximum intended load
• CTilt-up inserts 4 times, other inserts 2 times, and hardware 2 times
• DHardware 2 times and inserts equal to the member weight only

Unless a retaining device is used, excavated spoil next to a footing trench must be kept at least how far from the excavation edge under OSHA 1926.651?

• A6 inches
• B12 inches
• C2 feet
• D6 feet

A 5-foot-deep continuous footing trench is occupied by workers. OSHA 1926.651 requires a stairway, ladder, ramp, or other safe means of egress so that no employee has more than how much lateral travel to an exit?

• A10 feet
• B15 feet
• C25 feet
• D50 feet

When is a cave-in protective system required for employees in an excavation under OSHA 1926.652?

• AOnly when the excavation is deeper than 20 feet
• BIn every excavation 5 feet or deeper, unless it is entirely in stable rock or a competent…
• CNever if the crew will be in the hole less than 15 minutes
• DOnly when groundwater is visible

Before opening a footing excavation, OSHA 1926.651 requires the employer to determine the estimated location of what?

• AOnly overhead power lines
• BUnderground utility installations such as sewer, telephone, fuel, electric, and water lin…
• CThe nearest ready-mix plant
• DFinished floor elevation only

For a simple-slope excavation less than 20 feet deep in Type C soil, OSHA Subpart P Appendix B allows a maximum slope of which horizontal-to-vertical ratio?

• AVertical (90 degrees)
• B3/4 horizontal to 1 vertical
• C1 horizontal to 1 vertical
• D1 1/2 horizontal to 1 vertical

Who must inspect a footing excavation, adjacent areas, and protective systems before work starts, as needed during the shift, and after every rainstorm?

• AAny laborer on the crew
• BThe ready-mix driver
• CA competent person
• DOnly an OSHA compliance officer

How many cubic feet are in 1 cubic yard of concrete?

• A9
• B12
• C27
• D36

A slab-on-ground measures 30 feet by 20 feet and is 4 inches thick. What is the concrete volume to the nearest 0.1 cubic yard? Do not add waste.

• A4.4 cubic yards
• B7.4 cubic yards
• C8.9 cubic yards
• D22.2 cubic yards

A 40-foot by 24-foot slab is 6 inches thick. If the contractor adds 8 percent waste, how many cubic yards should be ordered, to the nearest 0.1 cubic yard?

• A16.4 cubic yards
• B17.8 cubic yards
• C19.2 cubic yards
• D21.3 cubic yards

For a given set of materials, which change most reliably increases hardened concrete compressive strength?

• ARaising the water-cement ratio
• BLowering the water-cement ratio
• CAdding water at the chute to raise slump after the design water is already in the mix
• DSkipping curing so the slab dries faster

A mixture contains 560 pounds of cement and 280 pounds of water per cubic yard, with no other cementitious materials. What is the water-cement ratio by weight?

• A0.40
• B0.45
• C0.50
• D0.80

A specification limits the water-cement ratio to 0.45. The mix uses 564 pounds of portland cement per cubic yard and no supplementary cementitious materials. What is the maximum mixing water, by weight, allowed per cubic yard?

• A127 pounds
• B198 pounds
• C254 pounds
• D282 pounds

Why is an air-entraining admixture used in exterior concrete in freeze-thaw climates?

• ATo eliminate the need for any curing
• BTo provide microscopic air voids that relieve freezing-water pressure in the paste
• CTo replace all coarse aggregate
• DTo make the concrete waterproof without a low water-cement ratio

Which ASTM C150 portland cement type is selected when high early strength is the primary need, such as cold-weather protection or early form stripping authorized by the engineer?

• AType I
• BType II
• CType III
• DType IV

Bleed water is standing on a slab. What is the correct finishing action?

• AStart hard-troweling immediately to seal the surface
• BBroadcast dry cement on the bleed water and trowel it in
• CWait until the bleed water evaporates or is removed and the concrete can support finishin…
• DAdd more water from a hose to keep the surface wet while troweling

What does a slump test primarily measure?

• A28-day compressive strength
• BAir content
• CConsistency and workability of fresh concrete
• DAggregate specific gravity

What is the primary purpose of internal vibration of freshly placed concrete?

• ATo add extra mixing water
• BTo consolidate the concrete by releasing trapped air and filling the form
• CTo raise the slump after the concrete has stiffened
• DTo replace the need for any form tightness

A continuous footing is 80 feet long, 24 inches wide, and 12 inches thick. A stem wall on that footing is 80 feet long, 8 feet high, and 8 inches thick. What is the total concrete volume to the nearest 0.1 cubic yard? Do not add waste.

• A14.8 cubic yards
• B16.0 cubic yards
• C21.7 cubic yards
• D29.6 cubic yards

What is the primary purpose of curing concrete?

• ATo cool the mix so it never hydrates
• BTo maintain adequate moisture and temperature so cement can continue to hydrate
• CTo dry the surface as fast as possible for early traffic
• DTo replace the need for a specified water-cement ratio

A January pour is scheduled for a spread footing. The subgrade is frozen. What is the correct action?

• APlace the concrete on the frozen soil so the heat of hydration thaws it
• BDo not place concrete on frozen subgrade; thaw and recompact or otherwise prepare a stabl…
• CDouble the slump and place as usual
• DOmit reinforcement so the footing can flex with thaw settlement

On a hot, windy day a slab surface starts to tear and form shallow, random cracks while the concrete is still plastic. What is the most likely cause?

• APlastic shrinkage cracking from rapid surface evaporation
• BAlkali-silica reaction, which appears within minutes of placing
• CToo much air-entraining admixture only
• DUnder-reinforcement of a fully hardened slab

What is the function of an isolation (expansion) joint in a slab-on-ground?

• ATo force a crack at a sawcut so panels remain connected by aggregate interlock only
• BTo separate the slab from walls, columns, or other fixed elements so they can move indepe…
• CTo serve as the only permitted construction joint in a building
• DTo increase the slab thickness at the edges

Under IBC 2021 Section 1907.1, the thickness of a concrete floor slab supported directly on the ground shall be not less than which value, unless a more specific design applies?

• A2 inches
• B2 1/2 inches
• C3 1/2 inches
• D8 inches

Six square columns are each 18 inches by 18 inches in plan and 10 feet high. What is the total concrete volume to the nearest 0.1 cubic yard? Do not add waste.

• A3.3 cubic yards
• B5.0 cubic yards
• C6.7 cubic yards
• D13.5 cubic yards

What is the principal reason to use a high-range water-reducing admixture (superplasticizer)?

• ATo increase slump and workability without adding water that would raise the water-cement…
• BTo entrain the air-void system required for severe freeze-thaw exposure
• CTo replace all portland cement in the mix
• DTo stop hydration so the load never sets

Honeycombing is visible on a stripped wall face. What is the most common construction cause?

• AToo much curing water after the wall has hardened
• BIncomplete consolidation, congested reinforcement, or grout leakage through the forms
• CUsing Type I cement instead of Type IV
• DSawcutting the wall the next day

IBC 2021 Section 1907.1 generally requires which vapor retarder under a concrete floor slab on ground, unless an exception or approved equivalent applies?

• ABuilding paper only, with no overlap
• BA 6-mil polyethylene vapor retarder with joints lapped at least 6 inches
• CA single layer of 1-mil painter's plastic
• DNo retarder is ever permitted under a slab

A load is 8 cubic yards. The mix has 517 pounds of cement per cubic yard and a water-cement ratio of 0.48, with no other cementitious materials. How many pounds of mixing water are in the full load?

• A1,241 pounds
• B1,654 pounds
• C1,985 pounds
• D2,480 pounds

Which combination is consistent with accepted cold-weather concreting practice?

• APlace on frozen ground and leave the concrete unprotected overnight
• BUse heated materials as needed, protect the concrete from freezing while it gains strengt…
• CAdd unlimited water so the mix cannot freeze
• DStrip all protection as soon as finishing is complete

What is a construction joint in cast-in-place concrete?

• AA full-depth isolation joint filled with premolded filler at a column
• BA planned stopping place in a pour where later concrete will be bonded or doweled to earl…
• CAny random crack that appears the next morning
• DA sawcut made only for appearance

Using 150 pounds per cubic foot for normalweight concrete, what is the self-weight of a 6-inch-thick slab, in pounds per square foot?

• A50 psf
• B75 psf
• C100 psf
• D150 psf

A 50-foot by 30-foot, 5-inch slab has four rectangular openings, each 4 feet by 4 feet, that will not be concreted. What net volume should be used, to the nearest 0.1 cubic yard? Do not add waste.

• A18.5 cubic yards
• B22.2 cubic yards
• C23.1 cubic yards
• D27.8 cubic yards

Replacing part of the portland cement with fly ash or slag cement typically has which early-age effect?

• AFaster early strength gain and higher heat of hydration in most ordinary replacements
• BSlower early strength gain and lower heat of hydration, with later-age strength often com…
• CImmediate 28-day strength with no need to cure
• DElimination of all shrinkage

Field-molded cylinders used to accept compressive strength are typically made and tested under which pair of ASTM methods?

• AASTM C143 slump and C231 air content only
• BASTM C31 for making and curing specimens and ASTM C39 for compressive strength
• CASTM C172 sampling only, with no strength test
• DA scratch test on the wall with a nail