How much stronger (percentage?) is a standard 3-core concrete block
vs. a standard 2-core concrete block? (8x8x16" blocks)

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Clarification of Question by bigcheek-ga on 24 Oct 2005 11:50 PDT

I'm a contractor.  I buy both 2 core and 3 core blocks.  The block
company I buy from says "sure, the 3 core are stronger, but we have no
idea how much".  I cannot find even a guess by Googling.

I'll assume the material is the same for each.

How will the blocks be loaded?
- compression or tension evenly distributed along the length of the block?
- compression or tension evenly distributed along the width of the block?
- compression or tension evenly distributed along the height of the
block (parallel to the holes for the core)?
- other type of loading? (some sort of moment?)

Also what is the wall thickness of the blocks?

I'm not looking for a technical answer.  Just a ballpark.  Most block
companies make both blocks.  This is assuming the load/compression is
the same.  Cores are vertical.  How much stronger would the 3-core be?
 Would it take 1 1/2 times the weight before collapsing?  No
horizontal movement considered.