In 1956, when cylinders were made on a jobsite, or air or slump was tested, the testing technician may or may not have known what he was doing. Too often, he did not, and the test results were likely to be unrepresentative of the concrete—sometimes leading to rejection of concrete that in reality met specifications. While poor testing can still occur, there is more protection when the testing technician is certified by the American Concrete Institute. ACI's Field Testing Technician certification program started in 1983. Once that program was written into ASTM C 94 in 1985 as a requirement for ready-mixed concrete, the program took off and hasn't looked back. In the meantime, other ACI certification programs were started, for flatwork finishers, lab technicians, construction inspectors, tilt-up supervisors, and shot-crete nozzlemen. An advanced flatwork finisher certification is currently being finalized that will certify finishers' knowledge of high tolerance floors. ACI has graded over 250,000 examinations in the past 25 years, and the program has been run in countries from Chile to Mongolia.
Read more highlights from 50 Years of Concrete Construction Progress.