1.4 Performance Exam Format and Grading

What Happens on the Performance Side

The performance examination is also closed book. ACI's program description states that it requires the actual demonstration of six of the required test methods and practices plus a verbal description of Practice C172/C172M (sampling). The candidate is judged on the ability to correctly perform, or describe where allowed, all of the required steps for each procedure.

This is a hands-on station test. An ACI examiner watches the candidate work through each procedure with real or simulated equipment and marks a checklist. Unlike the written exam, the performance exam does not produce a percentage score. Each procedure is graded pass or fail based on whether the candidate completed the required steps.

The Six Demonstrations Plus One Verbal Description

The seven standards are not all demonstrated the same way. Sampling (C172/C172M) is verbally described rather than physically demonstrated, because sampling a moving truck during an exam is impractical. The other procedures are performed for the examiner.

The "six demonstrations" cover the physical procedures, and the verbal description covers sampling. The candidate must be ready to speak the sampling steps clearly — locations, timing, compositing, and protection — exactly as if performing them.

Checklist Grading and Why Every Step Counts

The examiner uses a standardized checklist derived from each ASTM procedure. A typical checklist item is a single required action: select the correct rod, rod each layer the specified number of strokes, tap the mold the required number of times, strike off level, and so on. The candidate either does each step or does not.

Because grading is step-based and pass/fail, omitting one required step can fail an entire procedure. There is no partial credit that lets a near-complete demonstration pass. This is why experienced instructors tell candidates to narrate each step aloud while performing it — verbalizing forces the candidate to confirm the step happened and signals to the examiner that the required action was deliberate, not accidental.

How the Two Exams Combine

• The written exam is scored numerically with the 60%/70% dual rule.
• The performance exam is checklist-based and pass/fail per procedure.
• Certification requires passing both, and there is no averaging between them.

Preparing for the Format

The performance format rewards repetition under observation. Practicing each procedure until the step order is automatic, then having a peer or instructor run the checklist on you, mirrors exam conditions. Candidates who only watched demonstrations, but never performed them while talking through the steps, are the ones who freeze and skip a step at the table.

Which Air Method You Demonstrate

The two air methods, C231 (pressure) and C173 (volumetric), both measure air content, so the performance exam does not always require both. A candidate may be asked to demonstrate the air method appropriate to the equipment and concrete on hand, while still being responsible for knowing both on the written exam. Do not assume one is safe to skip in study: the written side can test either, and a session may call for either demonstration. The safest preparation is to be able to perform both meters cleanly.

Equipment and Setup Count

Many performance failures happen before the test even begins, during setup. Selecting the wrong rod, an unverified air meter, or a measure that has not been checked can cost checklist items. Treat equipment selection and setup as graded steps, because on most checklists they are.

The Verbal Description Trap

The C172 sampling verbal description is where candidates most often stumble, because describing is harder than doing. A complete description must cover the sampling locations within the discharge, the timing limits, the compositing of portions into one sample, remixing before testing, and protecting the sample from sun, wind, and evaporation. Candidates who can sample on a jobsite but have never spoken the procedure out loud tend to leave gaps. Rehearse the sampling description aloud, in order, until it is as automatic as the physical tests — the examiner is checking for each required element, not a general summary.

What the Examiner Is Looking For

The examiner is not trying to trick the candidate; they are confirming that each required action from the standard actually occurred, in an order that produces a valid result. That means small things matter: striking off level rather than mounded, tapping the mold the specified number of times to release entrapped air, selecting the correct rod for the specimen size, and reading a meter at eye level. A candidate who performs the broad strokes correctly but skips a consolidation tap or fails to clean the flange before sealing an air meter can lose the checklist item tied to that step.

There is also a difference between a step that is simply forgotten and one that is performed in the wrong order. Several procedures depend on sequence — for example, consolidating a layer before adding the next, or sealing and pressurizing an air meter before reading it. Doing the right actions in the wrong order can still invalidate the demonstration, so the candidate should rehearse not just the list of steps but the sequence of steps.

Because there is no partial credit, the difference between a confident pass and a failed procedure is often a single overlooked or out-of-order action that a few extra supervised rehearsals would have caught.