ACI Concrete Field Testing Technician - Grade I Practice Exam

The measurement for slump is specifically taken from the top of the mold to the original center of the specimen. This method is crucial because it provides an accurate representation of the deformation of the concrete after the mold has been removed. The slump test is intended to measure the consistency and workability of fresh concrete, and the distance measured reflects how much the concrete has settled under its own weight.

Using the original center of the specimen as a reference point ensures that variations in concrete placement or density do not skew the results, thus allowing for reliable comparisons across different tests. Each slump measurement is then standardized to this starting point to maintain consistency and accuracy in evaluating the concrete's properties.