1. Assuming, but not deciding, that liability to a materialman dealing with a subcontractor does not arise under the payment bond of a public works prime contractor where the materials are purchased and delivered for use in the prosecution of a public work but are not actually used in the construction thereof (but see cases cited in Ingalls Iron Works Co. v. Standard Acc. Ins. Co., 107 Ga. App. 454 (130 SE2d 606)), it does not follow that the time within which statutory notice of the materialman's claim must be given does not begin to run until the furnished materials are actually used. In order for a right of action to arise upon the payment bond of the prime contractor for the benefit of a materialman having a direct contractual relationship with the prime contractor, notice must be given "within 90 days from the day on which such person . . . furnished the last of the material . . . for which such claim is made." Code Ann. 23-1708.