Concrete Mix Design
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As stated before we pre-measure all of the materials into 1 gallon buckets.  This makes Quality control easy.

However more information on the volume of materials per batch is as follows:

Each bucket of Sand weighs  17 lbs.  x 2 buckets =                   34 lbs.
         "                Stone    "        16 lbs.  x 2     "         =                   32 lbs.
         "                Cement "        14 lbs.  x 2     "         =                   28 lbs.
Water per batch       ========================                     5 quarts +-.

Our company buys a lot of concrete from IMI (Irving Materials, Inc has 150 concrete plants in 4 states).  They perform tests daily on concrete cylinders produced by their customers.   We took the 4 cylinders to them for safe keeping the day after they were made.   When the cylinders were 14 days old they crusted two of them in a machine that determines the strengh of the concrete.  The first two cylinders tested at 4595 PSI and 5175 PSI for an average strenght of 4885 PSI @ 14 days.  The other two cylinders were tested at 28 days of age.  Those two cylinders tested out at 5584 PSI and 6825 PSI for an average of 6204.5 as a final strength.    We will round it down to call it 6200 PSI.  So the official strength of our design mix is 6200 PSI.  Which is way stronger than necessary.  
To officially determine the strength of this design mix we had the final product tested in August of 2007.   We made a batch of the concrete as described above and made 4 test cylinders. 
                            New Unionville and Western Railroad 
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