×
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

# How to calculate the amount of materials needed to fill a specific volume with concrete?

 Forum Search FAQs Links MVPs

## How to calculate the amount of materials needed to fill a specific volume with concrete?

(OP)
Hello all..

I'm doing a small project at my house with GFRC, with a mix of 1:1 cement to sand by weight, and I was wondering how can I calculate how much do I need for the mix to get the materials ready?
I calculated the volume that needs to be filled and it's about 4 cubic feet.

Thanks in advance

### RE: How to calculate the amount of materials needed to fill a specific volume with concrete?

alexmax....first, you don't need a 1:1 mix. 1 part cement to 3 parts aggregate is ok. If you use only sand and no coarse aggregate, along with the cement content you are using, you will get a lot of shrinkage and cracking. Since you only have 4 cubic feet to deal with, buy a few bags of premixed concrete mix (Sakrete or similar). It has proper proportions and will yield a reasonable strength of concrete without extraordinary shrinkage if you follow the directions. Each bag is about 1/3 of a cubic foot, so you'll need about 12 bags or so. At about 5 bucks a bag.....\$60.

### RE: How to calculate the amount of materials needed to fill a specific volume with concrete?

(OP)
Thank you Ron for your reply
Unfortunately premixed concrete is not available in my area, Also, I wanted a smooth surface therefor I wanted to eliminate aggregate and go with glass fiber reinforced concrete.

### RE: How to calculate the amount of materials needed to fill a specific volume with concrete?

Hi Alex,

The key to true GFRC is to sure to use alkali resistant glass fiber and a polymer formulated for the application. Both Ball (Smooth-on)and Nippon Electric Glass produce products under the name Forton and Polyplex respectively. Goon info on the products and process are on their websites. As far as volume goes the industry standard is to use the Absolute Volume method employing the specific gravity (SG) of the products to convert weight to volume. The SG of white portland cment (or gray) is 3.15, Water is 1.0 and most sands run around 2.7. The specific gravity will get you to the volume of the mix. Form there you can do a simple volume calculation. Figure at least 20% waste.

There is a good article on this by Dennis Clute, http://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nr...

Larry from Lehigh White Cement Company

#### 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!

Close Box

# Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!

Already a member? Close this window and log in.