N.C. Gen. Stat. § 136-34.1
The Department of Transportation is authorized, in its discretion, to furnish municipalities road maintenance materials to aid municipalities in the maintenance of streets upon agreement for reimbursement, as may be required by the Department and agreed to by the municipality. The agreement shall provide for reimbursement in an amount at least equal to the cost of the materials, together with the actual reasonable cost of any handling and storage of the materials and of administering the reimbursement agreement, all as solely determined by the Department. In no event shall the Department of Transportation be required to furnish road maintenance materials when, in the sole determination of the Department of Transportation, to do so would interfere with the maintenance of the streets and highways under its control. Notwithstanding any other provision of law, the provision of and reimbursement for materials under this section shall not be deemed a sale for any purpose.
N.C. Gen. Stat. § 136-34.1