coarse aggregate in slab-on-grade

[bjb]

For 8" and 10" thick interior concrete slabs-on-grade, I am specifying a maximum nominal coarse aggregate size of 1.5". What percentage should be retained on the 1" sieve?

 

[tincan]

#57 Gradation
% Passing 1 1/2"......100%
% Passing 1".........95-100%

 

[cfarmer]

In a January 2000 article of Concrete International there is a very good article called "24 Steps to Successful Floor Slabs"
Amoung other things, a 1 1/2" coarse aggregate with a 50 to 50 ratio of 3/8" aggregate is recommended.