FP-96 English Version - Eastern Federal Lands Highway Division

Section 552finished bents piers, or abutments until tests on concrete cylinders cast fromthe same concrete and cured under the same conditions as the substructureelement indicate that the concrete has attained at least 80 percent of the specifiedminimum 28-day compressive strength. This restriction does not apply toplacement of upper lifts for substructure elements cast in stages.Do not allow vehicles or construction equipment on any span until concrete inthe entire superstructure has attained its design compressive strength and hasbeen in place 21 days.For post-tensioned concrete structures, do not allow vehicles over 4,500pounds on any span until the prestressing steel for that span is tensioned,grouted, and cured, the grout has obtained a strength of 3,000 pounds persquare inch, and the tie rods are tightened. Vehicles weighing less than 4,500pounds may be permitted on a span provided the mass of the vehicle wasincluded in the falsework design.552.19 Acceptance. Material for concrete will be evaluated under Subsections106.02 and 106.03. Furnish a production certification for the portlandcement.The concrete mixture's slump, air content, unit mass, and temperature will beevaluated under Subsections 106.02 and 106.04. See Table 552-1 for specificationlimits. See Table 552-7 for minimum sampling and testing.Concrete compressive strength will be evaluated under Subsection 106.05.See Table 552-7 for minimum sampling and testing. The lower specificationlimit is the minimum required compressive strength at 28 days (f c k) specifiedin the contract. A single compressive strength test result is the average resultfrom 2 cylinders cast from the same load and tested at 28 days. See Table552-7 for the acceptance quality characteristic category.Remove and replace concrete represented by cylinders having a compressivestrength of less than 90 percent of the minimum 28-day compressive strength(f c k) and so located as to cause an intolerably detrimental effect on thestructure.401