Whenever the board of county commissioners of any county shall deem it expedient, or to the best interests of such county, to issue the county bonds of their county, for the purpose of constructing paved, macadamized, or other hard-surfaced highways, or erecting a courthouse or jail, or other public buildings, and funding the outstanding indebtedness of the county, or for any of such purposes, they shall determine by resolution to be entered in their records, what amount of bonds is required for such purpose, the rate of interest to be paid thereon, and the time when the principal and interest of such bonds shall be due and when payable.