×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

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!

*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

ASTM

ASTM

(OP)
How successful is ASTM 1231 which is testing of Concrete Cylinders using neoperene pad cap system?

RE: ASTM

We have done correlation studies of the pad caps and sulphur caps on many cylinders with strengths ranging from 2000 psi to over 8000 psi.  We use pad caps routinely for anything up to about 8000 psi.  Anything higher, we use conventional sulphur caps.

The pad caps work fine.  The break patterns are a bit different but the strength values correlate favorably with conventional caps.

RE: ASTM

(OP)
I have already tedested it.The fracture  is entirely different.What we get A farcture for a cylinder we r getting D fracture.The ASTM also says that it will damage the compression machine.Also the cylinders r to be tested for perpedicularity.In that way it is not working fine.I want Ron to reply to this.

RE: ASTM

Most often, the fracture pattern is a center shear break with small "raveling" on the top or bottom edges of the cylinder.  You will not likely see the typical shear-cone failure pattern.

What are your strengths and how many times have the caps been used?  Are you testing the cap liners for durometer hardness?  Why are the cylinders not perpendicular to the platen of the machine?

The pad caps should not cause significantly more damage to the machine than a full break with the sulphur caps.  The difference is that we know when the sulphur capped concrete has reached ultimate and can stop the machine, though we shouldn't if we follow ASTM procedures.  With the pad caps, there is no pre-fail warning so you have to break them to ultimate and shatter the specimen.

Ron

RE: ASTM

(OP)
Ron
We have started testing it initially for 10 cylinders.It showed D fracture even when the cylinder is perpendicular to the plane.I wanted to know that whether the fracture is important or not.And what is the comparison in rates with reference to capping and neoprene caps.W have used neoperene with 70 durometer hardness and we have cylinders that break between 3000psi to 5500psi.I want Ron to reply to this.

RE: ASTM

msharief...The break pattern is irrelevant as long as the correlation is good.  For our studies, using many cylinders, we found the correlation to be good even when the break pattern was not conventional.

Plot your sulphur cap results against your pad cap results and the bias will be immediately apparent if you have one.

Ron

RE: ASTM

msharief
        My office has used the pad caps for over 2000 breaks, virtually all concrete was less than 5500 psi. Our corrolations with sulfer caps, taken at random and as part of our ASTM & CCRL required comparisons have been good, AS LONG AS THE CYLINDER ENDS ARE IN GOOD CONDITION. Up until about a year ago we were corrolating at the rate of 5 pad caps to 1 sulfer cap. The sulfer has the advantage of taking care of minor to moderate end problems.  Of course, all problem cylinder ends should be cut or ground, but this doen't always occur.
        As far as damage to the machine, we have not observed any problems. The technician does have to exhibit a bit more care on the higher strength (more brittle) tests.

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



News


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