Materials sampling and testing follows AASHTO/ASTM standards as specified in the NC Materials Manual. Sampling frequencies: aggregates per 500 tons, asphalt binder per tanker load, concrete per 50 CY. Independent assurance testing at 10% of acceptance testing frequency. NCDOT operates certified testing laboratories per AASHTO R 18 (accreditation program). Field testing equipment calibrated per manufacturer specifications. Test results reported within 24 hours.
References: AASHTO current edition, NC Standard Specifications, FHWA Technical Advisories, and applicable federal regulations (23 CFR). Contractors shall maintain current copies of all referenced standards on the project site.
Source: NCDOT Construction Manual, 2024 Edition. Pages 25–26 of 29.