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

Bleeding on concrete

Bleeding on concrete

Bleeding on concrete

Lean concrete mix poured in a slab, 50 cm thick. Upon casting considerable bleed water appear on the surface (pic attached). The concrete mix tested for fresh properties like slump, air content, bleeding and found to be ok. The slump is about 18 cm and no bleeding observed at all.

But why is bleed water standing on the surface after few hours of casting. No water table beneath and the mix has more than 50% of fine aggregate even though the cement content is less (about 300 Kgs) as it is a lean mix 15 Mega Pascals at 28 days.

Kindly share your views.

RE: Bleeding on concrete

Concrete normally bleeds - say for slabs-on-grade.
Especially for a "lean" concrete as you state, there is possibly less Portland cement there to receive all the water and, well, it bleeds upwards.

Normal practice is to strike off the concrete and float. Then let the slab stand for a period and let the bleed water rise. Then pull off the water from the surface and finish the final troweling.

Check out Eng-Tips Forum's Policies here:
FAQ731-376: Eng-Tips.com Forum Policies

RE: Bleeding on concrete

The bleed water showing is excessive. It was likely caused by an error in the moisture content compensation at the time of batching, but as JAE noted, lean mixes are more prone to bleeding. You will likely see some "map cracking" at the surface and you will have lower abrasion resistance and lower general durability of the slab. Lean mixes are not a good idea for exposed slabs.

RE: Bleeding on concrete

Quote (concretebaby)

The slump is about 18 cm...
(7 inch slump). Too much water in the mix. IMHO, no structural concrete should have slump that high (unless superplasticizer is used). I would expect slump more like 8 cm to 11 cm.

www.SlideRuleEra.net idea

RE: Bleeding on concrete

15 MPa is not structural grade concrete, so anything goes with the mix design. It is only fit for things like replacing over-excavated areas under footings, etc.

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