What does ASTM C31 require for transporting concrete test specimens?

ASTM C31 outlines the proper procedures for preparing and transporting concrete test specimens to ensure their integrity and the reliability of test results. The requirement that specimens must be covered is crucial for protecting them from environmental factors that could affect their curing process and test outcomes. Covering the specimens helps to minimize moisture loss, prevents contamination, and shields them from extreme temperatures and direct sunlight during transportation. This step is fundamental in preserving the conditions under which the concrete was cured.

While attention to the other measures related to specimen transport is important, such as rapid transportation and proper marking for identification, the primary focus of this specific requirement hinges on the need to cover the specimens to maintain their quality until testing can occur.