Chapter 2

Question 1

Concrete made with portland cement will set and harden while under water. T or F?

Answer 1

True

Question 2

If a concrete slab on ground won't be exposed to sulfates, the cement used is most likely to be:
A. Type I
B. Type II
C. Type III
D. Type IV

Answer 2

A. Type I

Question 3

Fly ash may be added to concrete from a fly ash silo at the batch plant or from a silo containing a ______ cement.

Answer 3

blended

Question 4

Most concrete used in slabs on ground has coarse aggregate with a max size of:
A. 3/8 to 1/2in
B. 1/2 to 3/4in
C. 3/4 to 1-1/2in
D. 1 to 2in

Answer 4

C. 3/4 to 1-1/2in

Question 5

Sand for concrete used in slabs is easier to finish when it has close to the largest allowable amount of material passing the No. 50 and No. 100 sieves. T or F?

Answer 5

True

Question 6

Increasing the amt of sand in a concrete usually decreases the amt of water needed to make the concrete workable. T or F?

Answer 6

False

Question 7

All concrete that will be subject to freezing when moist or be exposed to deicing salts should contain:
A. an accelerating admixture
B. and air-entraining admixture
C. calcium chloride
D. and antifreeze agent

Answer 7

B. an air-entraining agent

Question 8

Strength of normal weight concrete depends mainly on:
A. Strength of the aggregate
B. mixing time
C. purity of the mixing water
D. water-cement ratio

Answer 8

D. water-cement ratio

Question 9

Oversanded concrete mixtures are likely to produce floors with poor wear resistance and excessive shrinkage. T or F?

Answer 9

True

Question 10

To minimize shrinkage and reduce cracking and curling:
A. use a much coarse aggregate as possible
B. use as little mixing water as possible
C. use aggregates with low shrinkage
D. all of the above

Answer 10

D. all of the above

Question 11

Changes in concrete slump most often represent changes in the amount of _______ in the mixture

Answer 11

water

Question 12

Air-entrained concrete is not recommended of use in concrete slabs:
A. exposed to freezing and thawing
B. exposed to deicing chemicals
C. finished by repeated steel troweling passes
D. finished by bullfloating and brooming

Answer 12

C. finished by repeated steel troweling passes

Question 13

Change is concrete temperature affect:
A. setting time
B. air content
C. slump
D. all of the above

Answer 13

D. all of the above

Question 14

To determine if concrete, in place, has the strength needed to put it into service, test cylinders should be:
A. stored for no more than 48 hrs in a moist environment at a temp of 60 to 80deg then stored at 73deg until they are tested
B. sorted in water at 73deg until they are tested
C. stored in a temp controlled job trailer
D. kept at the jobsite and cured under conditions similiar the the curing conditions for the concrete they represent.

Answer 14

D. kept at the jobsite and cured under conditions similiar the the curing conditions for the concrete they represent.