News Detail

Getting Results You Can Rely On

11/1/2011

When it comes to quality, hardened concrete ultimately speaks for itself in terms of load-carrying capacity and its resistance to service environment and natural hazards. While slump, air, unit weight, and 28-day cylinder strength are of interest for predictive purposes, concrete structures and pavements that have carried their applied loads and withstood real-world exposure are themselves the most reliable proof of acceptability.

But a lot of early decisions have to be made about the likelihood that the concrete is going to be able to meet owner expectations, so we don't have the luxury of waiting until the concrete is mature and experienced enough to speak for itself—thus, the need for testing. We collect a limited number of small samples of the fresh concrete and subsequently perform tests on specimens made from those samples. On the basis of test results, we determine acceptability of the material. And until the concrete has carried its full load, seen a number of seasons of environmental exposure, and resisted the forces it was designed to resist, the results of those standard tests are interpreted as speaking for the concrete.

Now, we can argue all day about whether any specific test was performed properly, or whether the tests were made from representative samples, or even if the right numbers were written down, but in the general case, once those numbers show up on a printed test report, they characterize the concrete with a gospel-like authority. With few exceptions, once the test report is issued, the strength (or other property) of the concrete is not what the concrete says it is, it is what the report says it is. Decisions about removing shores, applying prestressing, loading, accepting, and paying for the concrete are riding on the test results. And that means a lot is riding on the testing firm, their lab, facilities, equipment, and especially their testing technicians—thus, the need for certification.

ACI instituted its national test technician certification program back in 1980 precisely because accurate test results are vital to our industry. You can be sure that a card-carrying, ACI-certified test technician has proven his or her proficiency by passing a written test and by a live demonstration in front of the watchful eyes of qualified examiners. Further, to stay current with changing testing standards, ACI requires periodic recertification of individuals, generally every 5 years.

Starting with field test certification (testing slump, air content, unit weight, and temperature and making cylinders), ACI's program first expanded to certify flatwork finishers and now encompasses concrete construction inspectors; laboratory technicians who test concrete, aggregate, and base materials (soils); specialty commercial/industrial flatwork finishers and specialists; shotcrete applicators; and tilt-up technicians and supervisors. The newest program certifies installers of adhesive anchors and was developed to meet the needs of ACI Committee 318.

All told, there are now 18 programs in three languages, administered by over 1100 people working through 112 sponsoring groups headquartered in 15 countries. Oversight is provided by 14 ACI committees and subcommittees with over 200 members, along with nine staff support specialists at ACI HQ. Our certification teams have administered over 25,000 exams a year for the last 5 years, with over 101,000 active certifications held by individuals residing in 56 countries. ACI's China and Taiwan Chapters initiated programs last month and ACI is facilitating its first Chinese translations of certification materials. Programs for Masonry Testing Technician, Decorative Concrete Finisher, and Concrete Quality Technical Manager are actively under development.

While ACI certification activity takes place in your local community and around the world, one exciting place to watch ACI certification in action is at the World of Concrete (WOC) held annually in Las Vegas, NV. At WOC, ACI staff and volunteer examiners routinely administer over 200 written examinations to individuals who want to become certified Concrete Flatwork Finishers and Technicians, Specialty Commercial/Industrial Finishers and Technicians, and Tilt-Up Supervisors and Technicians. The Specialty Commercial/Industrial Finisher certification program also requires individuals to demonstrate their skills by finishing a full-scale concrete slab. It's quite a sight to see a large number of individuals being evaluated by certification examiners as they finish a tight tolerance concrete slab.

If you plan on attending WOC, I encourage you to visit the ACI certification staff at the ACI booth and learn more about our certification programs, and use the ACI promotional code (A21) to get free registration. C'mon down and show your support for better quality through certification!

Kenneth C. Hover
American Concrete Institute
kch7@cornell.edu

Back to Memo List