Building Construction Chp. 21 quiz questions

c. 1 in.

A #8 reinforcing bar has a diameter of a. 1/8in. b. 8 in. c. 1 in. d. none of the above.

b. water-reducing agent.

A high-strength concrete generally requires a a. water-increasing agent. b. water-reducing agent. c. sand-reducing agent. d. sand-increasing agent.

b. microscopic and amorphous silica.

A pozzolanic material must be composed mainly of a. microscopic silica. b. microscopic and amorphous silica. c. microscopic and crystalline silica. d. silica and alumina. e. amorphous silica and alumina.

False

A well-graded coarse aggregate is one in which the size of all aggregate particles is approximately the same. True False

b. Types I, II, III, IV, and V.

ASTM specifications classify Portland cement into five basic types, referred to as a. Types A, B, C, D, and E. b. Types I, II, III, IV, and V. c. Types PC1, PC2, PC3, PC4, and PC5. d. Types X, Y, Z, P, and Q. e. none of the above.

False

After concrete has been placed in the form, it should be consolidated as much as is economically practical. True False

c. 6,000 psi.

High-strength concrete is defined as concrete whose compressive strength is greater than or equal to a. 4,000 psi. b. 5,000 psi. c. 6,000 psi. d. 8,000 psi. e. 10,000 psi.

a. Types N and S lime.

Hydrated lime is available in two types, which are referred to as a. Types N and S lime. b. Types I and II lime. c. Types X and Y lime. d. Types A and B lime. e. Types 1 and 2 lime.

b. quicklime with water.

Hydrated lime is obtained by treating a. slaked lime with water. b. quicklime with water. c. limestone with water. d. slaked lime with Portland cement. e. quicklime with Portland cement.

c. chemical reaction of carbon dioxide in air with lime.

Hydrated lime-water paste sets and hardens due to the a. chemical reaction of water with lime. b. chemical reaction of oxygen in air with lime. c. chemical reaction of carbon dioxide in air with lime. d. chemical reaction of nitrogen in air with lime. e. chemical reaction of water in lime with carbon dioxide in air.

b. 1/4in.×1/4in.

In a No. 4 sieve, the dimensions of voids are approximately a. 4 in.×4 in. b. 1/4in.×1/4in. c. 2 in.×2 in., giving an area of approximately 4.0 in d. 1 in.×4 in. e. none of the above.

e. (b) or (c).

In a high-rise building, the concrete may be brought from the ground to the location of placement by a. chutes. b. buckets. c. pumping. d. (a) or (b). e. (b) or (c).

c. deformed wires, each with a cross-sectional area of 0.04 in.2.

In a welded wire fabric mat that has a designation of 8×8-D4.0×4.0, the number 4.0 indicates that the wires are a. deformed wires, each with a diameter of 4.0 mil. b. deformed wires, each with a diameter of 0.04 in. c. deformed wires, each with a cross-sectional area of 0.04 in.2. d. deformed wires, each with a cross-sectional area of 0.4 in.2 e. deformed wires, each with a cross-sectional area of 4.0 in.2 .

True

Lightweight structural concrete is heavier than insulating concrete. True False

a. heating crushed limestone and then pulverizing it.

Lime is made by a. heating crushed limestone and then pulverizing it. b. mixing crushed limestone with water and then pulverizing the mixture. c. mixing crushed limestone with sulfuric acid and then pulverizing the mixture. d. mixing crushed limestone with nitric acid and then pulverizing the mixture.

type 1: general purpose Type 2: high salt resistance used in roads around here type 3: fast setting grouts and mortar type 4: low heat when setting, dams and bridges type 5: salt resistant used in salt water

List various types of Portland cement and where they are typically specified.

a. 60 ksi.

Steel reinforcing bars, generally used in concrete, have a yield strength of a. 60 ksi. b. 80 ksi. c. 100 ksi. d. 120 ksi.

b. 28 days after casting the concrete in a test specimen.

The compressive strength of concrete is generally measured a. when the concrete is fresh. b. 28 days after casting the concrete in a test specimen. c. 14 days after casting the concrete in a test specimen. d. 7 days after casting the concrete in a test specimen. e. 1 day after casting the concrete in a test specimen.

c. using a power-driven rod vibrator.

The consolidation of concrete on a construction site are generally done a. manually using a 2-in.-diameter, 3-ft-long steel rod. b. manually using a 1-in.-diameter, 3-ft-long steel rod. c. using a power-driven rod vibrator. d. using a power-driven plate vibrator.

a. striking, floating, and troweling.

The finishing operations of a concrete surface usually involve striking, floating, and troweling. The sequence in which these three operations are generally performed is a. striking, floating, and troweling. b. floating, striking, and troweling. c. striking, troweling, and floating. d. troweling, floating, and striking.

c. limestone.

The main ingredient used in the manufacture of Portland cement is a. marble. b. granite. c. limestone. d. sand. e. iron ore.

d. Type I/II.

The most commonly specified type of Portland cement is a. Type C. b. Type III. c. Type PC1. d. Type I/II. e. Type II/III.

True

The rate at which concrete gains strength increases as the ambient air temperature increases. True False

d. workability of concrete.

The slump of concrete is a measure of the a. compressive strength of concrete. b. tensile strength of concrete. c. modulus of elasticity of concrete. d. workability of concrete.

a. when the concrete is fresh.

The slump of concrete is measured a. when the concrete is fresh. b. 28 days after casting the concrete in a test specimen. c. 14 days after casting the concrete in a test specimen. d. 7 days after casting the concrete in a test specimen. e. 1 day after casting the concrete in a test specimen.

b. 6-in. diameter, 12-in.-high cylinder.

The test specimen used for determining the compressive strength of concrete in the United States is a a. 6-in. diameter, 6-in.-high cylinder. b. 6-in. diameter, 12-in.-high cylinder. c. 6-in. diameter, 18-in.-high cylinder. d. 6-in. diameter, 12-in.-high cone.

co2 reacts with it which makes the mortar really hard. Slow setting

Describe how lime-sand mortar hardens and functions as cement.

quicklime corrodes metals and damages human skin. Slaked like is quicklime with that with water.

Describe the difference between quicklime and slaked lime.

more water is easier to work with but less strength

Discuss the importance of the water-cement ratio in concrete.

d. parking garages built in cold climates.

Epoxy-coated bars are generally used in a. high-rise buildings built in warm climates. b. parking garages built in warm climates. c. high-rise buildings built in cold climates. d. parking garages built in cold climates. e. none of the above.

True

Everything else being the same, a concrete with a larger coarse aggregate requires less Portland cement and water paste to give the same concrete strength. True False

allows the concrete to set up and gain strength and hold its shape

Explain what curing of concrete is, and why it is necessary.

b. volcanic ash.

One of the important cementitious ingredients in making Roman concrete was a. clay. b. volcanic ash. c. sand. d. Portland cement. e. none of the above.

a. water.

Portland cement sets and gains strength by virtue of its chemical reaction with a. water. b. oxygen in air. c. carbon dioxide in air. d. aggregates. e. none of the above.

False

Quicklime is most commonly used in building construction. True False

True

Quicklime reacts readily with water. True False

d. aggregate's particle size.

The aggregate for concrete is generally subdivided into coarse aggregate and fine aggregate. The distinction between the two types of aggregate is based on the a. aggregate's strength. b. aggregate's surface texture. c. aggregate's density. d. aggregate's particle size. e. aggregate's parent rock.

flyash, and air-entrainment used to add something extra to the concrete that the normal stuff doesn't offer

What is a concrete admixture, and why is it used? Discuss the commonly used concrete admixtures.

cement with air bubbles in it, used where you protection against the freeze thaw cycle

What is air-entrained Portland cement? Where is it typically specified?

a lot lighter than normal weight and only CA is used. costs more, but reduces dead loads

What is lightweight structural concrete? How does it differ from normal-weight concrete? What are the advantages and disadvantages of using lightweight structural concrete?

c. Fly ash

Which of the following materials is a pozzolana? a. Portland cement b. Lime c. Fly ash d. Sand e. Concrete

b. Type III

Which type of Portland cement is commonly used in making precast concrete members? a. Type C b. Type III c. Type PC1 d. Type I/II e. Type II/III

False

White Portland cement is generally weaker than normal (gray-colored) Portland cement. True False