Material numbers on a card indicate what?

Material numbers on a card primarily serve to identify the specific types of materials and their appropriate uses in construction or earthwork projects. This system helps in standardization, ensuring that workers can easily distinguish between different materials, their specifications, and any tests they may require for quality assurance. By referencing the material numbers, a project manager or field worker can quickly access information regarding how to properly use each material, along with any regulatory or safety measures that apply.

Understanding this concept is critical in maintaining efficiency and safety on job sites, as it prevents the mixing up of materials and ensures compliance with project specifications. In contrast, other options such as cost, quantity, or source are important but are not the primary focus of material identification in this context, hence support different aspects of material management rather than the direct identification and application of the materials themselves.