Quiz Chapter 7 & 8; Fibers & Reinforcement

CM 2050 Final

Match the correct fiber description with its appropriate type designation, as per ASTM C1666 - Type I

Steel Fiber-Reinforced Concrete

Match the correct fiber description with its appropriate type designation, as per ASTM C1666 - Type II

Glass Fiber-Reinforced Concrete

Match the correct fiber description with its appropriate type designation, as per ASTM C1666 - Type III

Synthetic Fiber-Reinforced Concrete

Match the correct fiber description with its appropriate type designation, as per ASTM C1666 - Type IV

Natural Fiber-Reinforced Concrete

Fibers are generally described as MICROFIBER or MACROFIBER. What is the size designation of a Microfiber?

Diameter less then .3mm

Fibers are generally described as MICROFIBER or MACROFIBER. What is the size designation of a Macrofiber?

Diameter greater than or equal to .3mm

Is the following a advantage in fresh concrete or hardened concrete - Reduces bleeding

Fresh Concrete

Is the following a advantage in fresh concrete or hardened concrete - Reduces Plastic Settlement

Fresh Concrete

Is the following a advantage in fresh concrete or hardened concrete - Increased Energy Absorption

Hardened Concrete

Is the following a advantage in fresh concrete or hardened concrete - Reduces Plastic Shrinkage Cracking

Fresh Concrete

Is the following a advantage in fresh concrete or hardened concrete - Less Temperature & Shrinkage Reinforcement Required

Hardened Concrete

All of the following are listed disadvantages of using fibers except

All the above are listed disadvantage.

Match the correct steel fiber description with its appropriate Type designation, covered in the chapter. Type I

Cold-drawn wire fibers

Match the correct steel fiber description with its appropriate Type designation, covered in the chapter. Type II

Cut sheet fibers

Match the correct steel fiber description with its appropriate Type designation, covered in the chapter. Type III

Melt-extracted fibers

Match the correct steel fiber description with its appropriate Type designation, covered in the chapter. Type IV

Mill Cut Fibers

Match the correct steel fiber description with its appropriate Type designation, covered in the chapter. Type V

Modified cold-drawn wire fibers

Which of the following is a disadvantage of using fibers in fresh concrete?

All of the above

The tensile capacity of concrete is approximately half of its compressive strength

False

Sometimes a seemingly trivial error in the location of reinforcement can have serious consequences.

True

Placing reinforcement in tension zone of concrete provides which of the following to concrete structures

All of the above

Reinforcing steel bars are also referred to as…

Rebar

True or false; reinforcing steel bars are well-suited for concrete reinforcement because they have low tensile strength and strain compatibility

False

True or false; Because reinforcing steel bars have high tensile strength, relatively small amounts are required in reinforced concrete.

True

Which of the following is a benefit of the bond relationship of reinforced steel bar and concrete?

All of the above

Which method is most commonly utilized to connect reinforced steel bars in flatwork, grade beams, and footings?

Wire tied

Rebar are hot rolled from steels with differing yield strengths. Which of the following yield strength is of grade 40 steel

40000 PSI

Rebar are hot rolled from steels with differing yield strengths. Which of the following yield strength is of grade 60 steel?

60000 PSI

What is the approximate bar diamter of No. 4 bar?

1/2”

What is the approximate bar diameter of No. 8 bar?

1”

What is the approximate bar diameter of no. 9 bar?

1 1/8”

What is the approximate bar diameter of no. 18 bar?

2 1/4”

True or false; Epoxy coating of reinforced steel bars provides a waterproof surface to enhance corrosion resistance.

True

True or false; Epoxy coated rebar are also way green in color to differentiate it from typical rebar

False

True or false; pre-tensioning is a method of prestressing in which tendons are tensioned before the concrete is placed

False

True or false; Post-tensioning is a method of prestressing in which tendons are tensioned before the concert is placed

False

In structural terms concrete failure is considered a

Sudden failure

In structural terms steel failure is considered a

Gradual failure

Which of the following is prefabricated reinforcing steel available in rolls of mats, discussed in class?

Welded Wire Reinforcement (WWR)

Steel reinforcement in concrete has improved and enhanced the construction industry because of the material bonding between concrete and reinforced steel. Which of the following bond is most active while the concrete is in a HARDENED state?

Mechanical Bond

Steel reinforcement in concrete has improved and enhanced the construction industry because of the material bonding between concrete and reinforced steel. Which of the following bond is most active while the concrete is in a plastic state?

Chemical bond

True or false; The addition of steel reinforcement in concrete significantly increases the load capacity and ductility.

True

The materials required to be combined to obtain reinforced concrete are

All of the above

The two (2) two main requirements/principles of quality reinforcing concrete are

Adequate amount of steel and steel placed in correct location

Which of the following is most important when utilizing reinforcing bars in concrete?

All of the above