Bridge building contractors who work under ODOT Supplemental Specification 898 are required to use the services of a "certified laboratory" (see 898.02) to test raw materials and produce a concrete mix design which meets the requirements of S.S. 898. The certified laboratory's mix design is approved by an ODOT engineer before being incorporated into any work (see 898.07). The certified laboratory also tests the plastic concrete as it is placed in the structure as part of the contractor's quality control (QC) and acceptance testing. As a check, ODOT also tests the plastic concrete, although at a reduced frequency (898.11). Finally, the certified laboratory tests the hardened concrete for acceptance and final payment (compressive strength and permeability - (898.15) with ODOT also performing some companion testing for quality assurance (898.11).
