Chapter 21 Flashcards
Lime is made by doing what?
Heating crushed limestone and then pulverizing it
Quicklime reacts readily with water. True or false?
True
Hydrated lime is obtained by treating what?
Quicklime with water
Quicklime is most commonly used in building construction. true or false?
False
Hydrated lime-water paste sets and hardens due to the ?
Chemical reaction of carbon dioxide in air with lime
Which of the following materials is a pozzolana?
a. Portland Cement
b. Lime
c. Fly ash
d. Sand
C. Fly ash
One of the important cementitious ingredients in making Roman concrete was?
Volcanic Ash
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
A. Types N and S lime
A pazzolanic material must be composed mainly of:
a. micrscopic silica
b. microscopic and amorphous silica
c. microscopic and crystalline
b. microscopic and amorphous silica
The main ingredient used in the manufacture of Portland cement is?
Limestone
ASTM specifications classify Portland cement into five basic types, referred to as:
a. Types A, B , C , D, E
b. Types I, II, III, IV, and V
c. Types PC1, PC2, PC3, PC4, and PC5
b. Types I, II, III, IV, and V
The most commonly specified type of Portland Cement is:
Type I/II
Which type of Portland cement is commonly used in making precast concrete members?
Type III
White Portland cement is generally weaker than normal Portland cement. True or False
False
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:
Aggregate’s particle size
In a No. 4 sieve, the dimensions of voids are approximately:
a. 4 in. X 4in
b. 1/4 in. X 1/4 in.
c. 1 in. X 4 in.
b. 1/4 in. X 1/4 in.
A well-graded coarse aggregate is one in which the size of all aggregate particles is approximately the same. True or False
False
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 or False
True
Lightweight structural concrete is heavier than insulating concrete. True or False
True
The slump of concrete is measured:
a. when the concrete is fresh
b. 28 days after casting the concrete test specimen
c. 14 days after casting the concrete specimen
when concrete is fresh
The slump of concrete is measured by:
a. compressive strength of concrete
b. tensile strength of concrete
c. workability of concrete
c. Workability of concrete
The test specimen used for determining the compressive strength of concrete in the United States is a :
a. 6in. diameter, 6in. high cylinder
b. 6in. diameter , 12 in. high cylinder
c. 6in. diameter, 18in. high cylinder
b. 6in. diameter, 12 in, high cyinder
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
b. 28 days after casing the concrete in a test specimen
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
b or c
After concrete has been placed in the form, it should be consolidated as much as is economically practical.
True or false?
False
The consolidation of concrete on a construction site are generally done:
a. Manually using a 2in diameter, 3 ft long steel rod
b. manually using a 1in diameter, 3 ft long steel rod
c. using a power-driven rod vibrator
d using a power-driven plate vibrator
c. using a power-driven rod vibrator
The finishing operations of concrete surface usually involve striking, floating, and troweling. The sequence in which these three operations are generally performed is?
Striking, Floating, and troweling
Portland cement sets and gains strength by virtue of its chemical reaction with?
Water
The rate at with concrete gains strength increases as the ambient air pressure increases. True or false?
True
High strength concrete is defined as concrete whose compressive strength is greater than or equal to how much psi?
6,000psi
A high strength concrete generally requires a:
a. water-increasing agent
b. water reducing agent
c. sand reducing agent
d. sand increasing agent
b. water reducing agent
Steel reinforcing bars, generally used in concrete, have a yield strength of how much ksi?
60ksi
A #8 reinforcing bar has a diameter of:
a. 1/8in.
b. 8in.
c. 1in.
d. none of the above
c. 1in.
In a welded wire fabric mat that has a designation of
8 X 8-D4.0 X 4.0, the number 4.0 indicates that the wires are?
Deformed wires, each with a cross-sectional area of 0.04in squared.
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
d. parking garages built in cold climates
d. parking garages in cold climates
