bulk density of 3/4 stone

Kempe's Engineers' Yearbook, any edition, contains that sort of thing.

Machinery's Handbook lists "gravel" at 109 pounds.

But the problem there is that "gravel" is not "3/4 stone".

Harumph!

Gravel is small stones and pebbles. 3/4" stone is small, therfore, it's gravel.

109 lbs per cubic foot is close. It can vary much with moisture content and density of rock from which it's made (typically granite -- varies in density from planet to planet and from state to state, and from country to country, etc., ad infinitum).

I was assuming he wanted the density of a "processed gravel" (3/4-inch stone) which has smaller (than 3/4-inch) particles removed by a washing or screening operation so as to produce a coarse aggregate material. I make this assumption because OP specifically mentions "3/4 stone". For gravel, the bulk density can be higher up to 130 lbs/cf as the voids are filled with sand and smaller (than 3/4") stone. We need to know the gradation of the gravel to answer this question (which has yet to have been asked.

However, it is up to Mr. Guest to clarify this point and he seems to have stepped away.

Gradation is often specified when dealing with crushed rock or gravel used for bedding or otherwise. For example ("Design of Small Dams" by US DOI Bureau of Reclamation, Appendix "G" Specifications) this excerpt:

The grain size ratios shall be within the limits shown below:

15 percent grain size coarse aggregate =12 to 40

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15 percent grain size sand

50 percent grain size coarse aggregate =12 to 58

_________________________________

50 percent grain size sand

where 15 percent grain size indicates the size of screen opening that will pass 15 percent, by weight, of the total material, and 50 percent grain size indicates the size of the screen opening that will pass 50 percent, by weight, of the total material.

The point I am making is that "gravel" is a material whose properties (including but not limited to "bulk density") differ materially (no pun intended) from the material known in industry as "3/4 stone". We should take these differences into account in replying to the OP.

Point well taken, and I'm not ignorant of any of the stuff you mention.

Judging by the simplicity of the OP's question, I merely assumed that he didn't know anything, and he never bothered to search for definitive answers on the internet.

Because of you in-depth explanation, I'm going to give you a "Good Answer" vote.

Often times Mr. Guest asks interesting questions by accident.

The challenge always seems to be whether to give an answer which might work, or expand/interpret the question as if this where a physical classroom rather than cyber-class.

Suppose for example, that this same question where asked by the student in a physical classroom at Clemson University. My response would be as follows:

Mr. Guest Murphy, would you like to rephrase your question to be "what is the bulk density of gravel used as the coarse aggregate for the 3,500 psi ready-mix concrete design problem that we studied in yesterday's class? Surely Mr. Murphy you know by now from the lesson learned last Tuesday that 3/4-inch stone is not the proper way to specify this coarse aggregate."

Murphy then replies, "sorry, but I missed that class and have not had a chance to review the lecture notes because my dog ate them was sick".

To which I reply, "Mr. O'Toole, offer Mr. Murphy some help on this one. Refresh Mr. Murphy's memory on the gradation curve and sieve test requirements for the coarse aggregate that we have designed for the concrete mix".

O'Toole produces his gradation chart for the coarse aggregate.

I reply, "Thank you Mr. O'Toole. Make a copy of the gradation curve and give it to Mr. Murphy. Mr. Murphy, plan to stop by the soils lab tomorrow afternoon to run this sieve test using Mr. O'Toole's aggregate. Once you get the proper blend, weigh it and report your results back by Friday."

Mr. Murphy then replies, "Yes sir".