ASTMs

Question 1

ASTM C143 Standard Test Method for Slump of hydraulic-Cement Concrete Procedure

Answer 1

1. All equipment dampened
2. Fill cone in 3 equal lifts, rodding 25 times, each time penetrating the layer below by 1”
3. Each lift should fill a third of the volume.
4. After the last rod, screed the material off the top and wipe any concrete from the base of the cone.
5. Pull cone straight up, 3-7 secs
6. Measure slump from the top of the mold to the displaced original center
7. Begin and complete test in 2-1/2 minutes.

Question 2

ASTM C231 Standard test method for air content of freshly mix concrete by the pressure method

Answer 2

Determines the air content of normal and heavyweight concretes, not for lightweight concrete. It’s necessary for concrete exposed to cycles of freezing and thawing.

Question 3

Concrete sampling must be done at a minimum of:

Answer 3

(1) At least once a day
(2) At least once for each 150 cu. yards of concrete
(3) At least once for each 5000 sq. ft. of surface area for slabs and walls

(26.12.2.1(a))

Question 4

Core specimens are considered acceptable if:

Answer 4

1) The average of 3 cores is equal to at least 85% of f’c
2) No single core is less than 75% of f’c

Question 5

28-day acceptance of strength is the average of:

Answer 5

(3) 4x8 cylinders or (2) 6x12 cylinders

(26.12.1.1)

Question 6

ASTM C1064 Test for Temperature procedure

Answer 6

Place temp device at minimum of 3” into freshly mixed concrete.
Leave for minimum 2 minutes and max of 5 minutes.
Record temp to nearest 1°F.

Question 7

“High slump” and “Low slump” refers to:

Answer 7

The number of inches the concrete subsides when the cone is remove. “High” when it slumps a lot- indicating wet, fluid or soft concrete. “Low” — indicating, dry or stiff concrete.

Question 8

Minimum number of strength tests per project:

Answer 8

Five strength tests from (5) randomly selected batches, or from each batch if fewer than five batches.

Question 9

Strength tests if quantity is less than 50 cu yds:

Answer 9

Strength test may be waived by building official if evidence of satisfactory strength is submitted.

Question 10

Procedure for 6x12 cylinders:

Answer 10

The molds should be filled 1/3 full and rodded exactly 25 times with a 5/8 inch diameter tamping rod. The second and third layers are similarly placed.

Question 11

Procedure for 4x8 cylinders:

Answer 11

The molds should be filled in two layers of approximately equal depth and rodded with a 3/8 inch diameter tamping rod.

Question 12

Water/ Cementious ratio=

Answer 12

lb water/ lb of cement

(1 gallon = 8.33 lbs)
(1 pound cement = 94 lbs)