What is the required thickness of a metal slump cone according to standard C143?

The required thickness of a metal slump cone according to standard C143 is specified as .060 inches, with no individual measurement being less than .045 inches. This standard sets the criteria to ensure the integrity and durability of the slump cone during testing, as it needs to withstand the forces during the concrete placement and testing process without deforming.

By establishing a minimum thickness, standard C143 ensures that the slump cone maintains its shape and dimensions under the stress applied during the test, helping to achieve accurate and consistent slump measurements. The specification that no measurement should be less than .045 inches ensures further quality control in the manufacturing of the cone, which is essential for reliable testing results.

The other options do not meet the specific thickness requirements laid out in C143, making this choice the only correct one in the context of the standard's guidelines.