Concrete strength testing per AASHTO T 22 (compressive strength of cylinders). Cylinder fabrication per AASHTO T 23 in the field. Standard curing: lime-saturated water at 73.4°F ±3°. Testing frequency: one set of cylinders (4 minimum) per 50 CY or per day of placement. 28-day strength required for acceptance. 7-day strength for information. Caltrans uses statistical evaluation: f'c represents the specified strength; individual tests shall not be more than 500 psi below f'c.
All work under this section shall comply with Caltrans current standards and applicable AASHTO, ASTM, and federal requirements. The Engineer has authority to accept or reject materials and workmanship that do not conform to the specifications.
Source: Caltrans Materials Testing Manual, 2024 Edition. Pages 11–12 of 25.