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

Y this curves come like this?

Y this curves come like this?

Y this curves come like this?

This is a relationship between moisture content and dry density. Blue curve is for standard proctor test.( 2.5kg,30cm,3 layers, 27 bowls , in 1L mould = 595.9575kJ/m3) and for red one is like modified proctor test but (4.5kg, 45cm ,5 layers ,35 bowls ,in CBR mould(4L) =896.1046875 kJ/m3 ) . But I expect red one to move left side with moving top . But actualy I got this. What is the reason?

RE: Y this curves come like this?

I have seen this when the samples (in this case the modified set) was not allowed enough time to 'set' and allow the moisture to penetrate the soil (clayey?) particles before compaction. The shape of the modified curve also fit this scenario.

RE: Y this curves come like this?

Yes...agree your curves are backward. Also agree with emmgjld that you can get some strange results in clayey soils, silty soils and clayey-silty soils.

I also note that your moisture points are about 4 percent apart. That's a rather large separation and can sometimes cause issues with defining the maximum dry density. Further, the energy input was varied on the modified Proctor, so it makes standard comparison more difficult.

It would also be a bit easier to discern issues with the test if you could show the zero air voids curves for your soils.

Many clayey soils (and other fine grained soils), as emmgjld noted, need to be "pre-soaked" before running the Proctor test. My typical procedure was to mix the soil in at different moisture contents in 4 separate plastic concrete cylinder molds, seal them from moisture loss, and let them sit overnight. That way the moisture has an opportunity to permeate the samples, making the curve more accurate and predictable.

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! Already a Member? Login


Research Report - How Engineers are Using Remote Access
Remote access enables engineers to work from anywhere provided they have an internet connection. We surveyed our audience of engineers, designers and product managers to learn how they use remote access within their organizations. We wanted to know which industries have adopted remote access, which software they are using, and what features matter most. Download Now
eBook - Managing the Context of Product Complexity Using the Digital Twin
Keeping track of changes to complex products is difficult—think Aerospace & Defense equipment, new generations of commercial aircraft, and software-based automobiles. A new way to managing the digital context of the physical product is required and the answer is the Digital Twin. This ebook explores the opportunity available for Operations and Maintenance for the Digital Twin. Download Now
White Paper - Trends in Industrial Filtration
Substantial progress has been made in filtration technologies in recent years. New filter media materials, designs and processes have led to filters that are more efficient, reliable, compact and longer lasting. This white paper will discuss the various trends that are impacting operational responsibilities of MROs today and the resources that are available for staying up-to-date on the latest filtration solutions. Download Now

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:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close