Who must plot the results of gradation tests on Concrete Aggregate Control Charts?

The responsibility for plotting the results of gradation tests on Concrete Aggregate Control Charts falls to the contractor's Certified Concrete Technician. This individual is specifically trained and certified to ensure that concrete aggregates meet the necessary specifications for projects. By managing the control charts, they play a crucial role in quality assurance and process control, continuously monitoring the gradation of aggregates to maintain compliance with specifications.

Other roles, such as the Project Manager or testing laboratory supervisor, have different responsibilities that may involve overseeing overall project management or testing protocols but are not typically engaged in the day-to-day hands-on plotting of gradation test results. An independent inspector may assess compliance but is not tasked with maintaining the control charts. Thus, the certified technician is the most appropriate choice for this specific task.