What's This Report For? Part 2: Cement Mill and Concrete Test Reports-The Concrete Test Report-What the designer needs to know (PDF)

The Concrete Test Report-What the designer needs to know (PDF)

Pdf Summary

The article "The Concrete Test Report: What the Designer Needs to Know" by Luke M. Snell appears in the December 2010 issue of Concrete International. It discusses the essential role of concrete test reports in ensuring the correct concrete delivery to job sites and verifying that it meets specified requirements. Initially, a report is issued after the 7-day concrete break and updated with 28-day results, often accumulating rapidly in large projects due to their frequency. The reports document compliance with ASTM standards, include identifying data, job site information, sampling and curing details, compressive strength, and fracture patterns.<br /><br />Significant focus is given to interpreting results accurately and understanding that preliminary 7-day results are not definitive, especially if fly ash is included, potentially delaying typical strength gain. The article emphasizes the importance of averaging multiple cylinder tests for accuracy, as a single test can mislead.<br /><br />If a test result does not meet ACI 318-08 criteria, outlined correction measures target both current concrete and future placements. Key suggestions include verifying procedures for making specimens according to ASTM Standards to avoid artificially low results. Checklists cover areas such as improper handling, temperature variations, excessive relief or loading issues, and accounting for high air content or on-site water additions that could compromise test results.<br /><br />Improving future results involves monitoring procedural adherence, technician and lab certifications, batch ticket comparisons, and adjustments for temperature impacts. The article advises tracking concrete strength over time to catch deviations early on, advising the use of nondestructive testing to pinpoint issues. Sound judgment is required to deal with substandard concrete, potentially involving core sampling or nondestructive methods to avoid unwarranted demolition or incurring extra costs, ensuring cost-efficient and timely construction project completions.

Keywords

concrete test reports

ASTM standards

compressive strength

7-day results

28-day results

ACI 318-08

nondestructive testing

fly ash

core sampling

construction quality