10.2 Category Scoring and the No-Compensation Rule

You Need the Overall Score and Every Method Minimum

The most important scoring rule is that the written exam has two passing requirements. A candidate needs at least 60 percent correct for each required test method or practice and at least 70 percent correct overall. These requirements work together. A strong total score does not erase a failed method category, and passing every method category does not help if the total score remains below the overall requirement.

The written exam has 55 questions. Seventy percent of 55 is 38.5, so a candidate needs at least 39 correct answers overall. That number is not enough by itself. If the missed questions are concentrated in one category, the candidate can still fail the written exam under the method minimum rule.

This table matters because ACI states that written questions are spread across the ASTM methods and practices, with between five and ten questions on each. You may not know the exact category count while taking the exam. During study, assume every method needs a margin above the minimum. If you regularly score only 3 of 5 on one method, one careless mistake can drop that category below passing.

Consider a candidate who answers 42 of 55 questions correctly overall. That is above 70 percent. If the candidate answers only 2 of 5 sampling questions correctly, the written exam is still not passed because the sampling category is below 60 percent. Now consider a candidate who meets 60 percent in every method category but totals only 38 of 55. That candidate still misses the overall 70 percent requirement.

This rule should shape the study plan. Do not take ten mixed practice exams and celebrate only the total percent. Break every practice set into C172 sampling, C1064 temperature, C143 slump, C138 density, C231 pressure air, C173 volumetric air, and C31 specimens. The weakest method controls risk because it can fail the written exam even when the total looks comfortable.

Use this scoring routine after every practice test:

1. Count total correct out of 55 and confirm whether it is at least 39.
2. Sort each missed question by method or practice.
3. Compute category percent for each method.
4. Flag any method below 75 percent as a risk, even if it is above 60 percent.
5. Re-study the exact method concepts behind those misses.
6. Retest weak methods with small focused sets before another full mixed set.
7. Keep a final readiness sheet that shows both total score and method scores.

The no-compensation rule is good news if you use it early. It tells you exactly where risk lives. A candidate who finds and fixes a weak category during practice avoids discovering the problem on the official written exam.