×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Percent Voids for Gravel
3

Percent Voids for Gravel

Percent Voids for Gravel

(OP)
I am using gravel as a bedding underneath an open bottom valve/drain box and im not sure what percentage of voids we should assume for gravel? Any help on this issue, I would appreciate it.  

RE: Percent Voids for Gravel

30-40% void is normal for gap graded gravel.

RE: Percent Voids for Gravel

I'd use 1/3rd.  Bear in mind that you can also measure it yourself.  Take the specific gravity of the aggregate, multiply it by the unit weight of water and that would be the density if there were no voids. Then take the bulk density of the aggregate and figure out how much is lost to air voids.

Example:  
Specific gravity of the aggregate is 2.7
void-free density would then be 168.5 pcf
bulk density (dry) of the aggregate is 112 pcf.
void ratio is 1-(112/168.5)=0.34

Hope this helps.

f-d

¡papá gordo ain't no madre flaca!

RE: Percent Voids for Gravel

I use 30% for infiltration trench storage.

Mike McCann
MMC Engineering

RE: Percent Voids for Gravel

If you have a sample of the material, it's easy to measure.  Fill a gallon container with the gravel and see how much water you can add.
 

Peter Smart
HydroCAD Software
www.hydrocad.net
 

RE: Percent Voids for Gravel

psmart...only valid if the aggregate is saturated, surface dry.  If the aggregate is completely dry, then can be off by as much as 5 or 6 percent, depending on absorption.

Use weight-volume relationship as suggested by fattdad.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources