concrete tech training 1

[boffintech]

For training purposes of green concrete technicians (no pun intended) I have the following as part an exercise. What other interesting questions (w/answers) should I be asking on something like this?


Given the Proportions for 1 yrd3 of concrete

Type I Portland Cement 752 lbs
Fine aggregate 1050 lbs
Coarse aggregate 1100 lbs
Maximum water to cement ratio .5
Pozzolan 4 1/2 lbs per sack of cement

Hint: water weighs 8.33 lbs/gallon

1) How many sacks of cement are in one cubic yard of this concrete?

2) Approximately how much does 200 gallons of water weigh?

3) What is maximum amount of water (in gallons) that may be added to 6 yrd3 of this mix?

4) If the aggregate contains 2% free moisture, how much water is that (in gallons) for 1 yrd3 of this mix?

 

[henri2]

The absolute volume of this mix does not appear to be 1 cu.yd. Divide each of the ingredients by the specific weight (SG x 62.3pcf), add them up and see if you come up with 27 cu.ft.

Assume the following SGs: cement = 3.15....aggregates = 2.65...fly ash = 2.3...and water = 1

Question 3 should come after 4 and should be worded " If 200 gal are used in batching 6 cu.yd of this mix and the fine aggregate contains 2% moisture on SSD basis, how much additional water is permitted to be added?"

Additional questions can deal with:

(i) Yield calculations---when fresh unit weight value is provided

(ii) Fitness of mix for durability--see ACI 318 Chapter 4