I read somewhere that in a properly designed mix,one using smaller aggregate will crack less than a mix using large rock.Any technical references out there?

I don't think so, it's the paste that shrinks. And being that a small rock mix has more 'surface area' than a big rock mix, it requires more paste. Facts: (1) concrete is grey (without color added, obviously) (2) concrete shrinks Beyond that it's anyone's guess as to what goes on with it.

Burns & Mcdonnell:

http://www.burnsmcd.com/portal/page/portal/Internet/Content_Admin/Publications%20Repository/TechBriefs%20Link%20Repository/article-designandconstructionofliquidtightconcretestruct.pdf

"Using a higher proportion of large aggregate to fine aggregate reduces the total surface area of the aggregate, hence reducing the water absorption into the aggregate."

The key point is use the least amount of water to prevent cracking.

well i was told there are 2 guaranties in concrete , one is that it will dry, and 2 is that it will crack, lol.

were and why is redundtant, it will crack, guarantied.

ALL CONCRETE CRACKS. THE WAY AROUND IT IS, YOU CONTROL THE CRACKING BY CUTTING CONTROL JOINTS. RULE OF THUMB WOULD BE EVERY TEN FEET, CUT COMING OFF A CORNER AND CUT WHERE YOUR ELEVATION CHANGES.

http://www.ansi.org/

this site should answer all your questions.

Put in all large rocks and replace all the water with admix.  Then keep the cement content to minimum and call the belt because it won't pump.

a finishers job is to place, finish and cure. while calling the shots considering that the material is fine the only failior would be workmanship. example is two locations and the first one proptly cracks due to being a cold joint. all the contractor knows is that he has a problem. yea the pump worked fine ha ha.   

coming from a saw cutter and pump operator, saw cut since I was out of high school, no matter what concrete cracks, the only way I have cut it to a minimum was pouring some of my own form and finish projects by using rebar or wiremesh plus fiber mesh that really cuts down on surface cracks as for saw joints even if you softcut you will never stop cracking completely that I will guarantee.

Granted 3/8th presents it's own problems,however one must use within a spectrum.Rebar/wire mesh helps a bunch but explansive soils will move a battleship.Soft cutting works only in areas that are not subjected to freeze thaw conditions,ie outside.In those applications hand tooling works,must be 1/4 of slab thickness.Most people I know sell a 2x4 as 4",yeah,right.The v on a cutter allows the moistured to freeze and expand upward,therefore eliminating surface pressure.

Rebar,never use anything less than grade 60,HD and lowes does grade 40.Also rebar placement needs to be a little tighter,closer to 12" spacing,not 18"-4" as I often see.Control joint spacing also needs to be tighter (I do with everything).One must understand mixes,using a hi range water reducer,cut flyash to 10%,and don't use water to gain set time/ease of working,Also one should learn all about Delvo,your best friend.

Finally,bid your work accoringly.Put the right stuff in and charge for the mixes,less grief.Oh,almost forgot,use confilm not water on surface.

if you use a finishing compond or liquid it will also check crack and the water gets un the top finish then it freezes and pop goes the top