Low Compressive Strength Test Results? What They Mean and Next Steps...

January 20, 2021
11:30 AM - 12:30 PM
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Zoom Meeting


About the Topic

Compressive strength tests are used for concrete acceptance based on criteria defined in ACI 318 and ACI 301. Tests results not meeting these criteria are referred to as low strengths. This presentation covers the “low strengths” topic in detail and provides answers to questions such as: what is considered a strength test and what is not, what the minimum frequency of testing is, what the acceptance criteria for strength tests are, and how to investigate strength tests not meeting the acceptance requirements. In addition, steps needed by a concrete supplier, in case acceptance criteria are not met, will also be discussed. To better understand discussed concepts, the presentation will use statistical concepts and numerical examples. A list of reading resources will be provided for those interested to study it in more detail.

Topics covered in this presentation include:

  • Definitions related to strength testing
  • Methods of sampling, fabrication, handling, and curing strength test specimens
  • Acceptance criteria for strength tests
  • Interpretation of strength test results not meeting acceptance requirements
  • Investigation of non-compliant concrete
  • Addressing low strength concrete issues in production
About the Speaker

Jerzy Zemajtis, PhD, PE, is a Senior Engineer at ACI. His role at ACI is to provide technical and administrative support to ACI's Technical Committees. He received his BS and MS in civil engineering from the Technical University of Gdansk, Poland, and his PhD in civil engineering from Virginia Tech.

Mr Zemajtis worked as a Structural Engineer in Virginia Beach, VA, and Vancouver, Canada, and as a Civil/Materials Engineer at Construction Technology Laboratories in Chicago, IL, before joining the ACI Engineering Department in 2010. He is a licensed engineer in Washington and British Columbia.

Registration Fees
Members: $10
Non-Members: $20

Registration fee includes webinar presentation, and a certificate for 1.0 Professional Development Hour (PDH) to be emailed to each registered attendee at the conclusion of the presentation.

This webinar is approved for ICC continuing education credits.

Registration Deadline

The deadline to register for this event is January 18, 2021.

Cancellation Policy
You can cancel your registration by close of business on January 18, 2021, and receive a refund. There are no refunds given for cancellations made after January 18, and no-shows will be billed.


$10.00 Members

$10.00 Additional Company Member

$20.00 Non-Members

$10.00 Additional Company Member