FP-96 English Version - Eastern Federal Lands Highway Division

Section 552Do not place concrete until the forms, all embedded material, and the adequacyof the foundation material have been inspected.Remove all mortar, debris, and foreign material from the forms and reinforcingsteel before commencing placement. Thoroughly moisten the formsand subgrade immediately before concrete is placed against them. Temporaryform spreader devices may be left in place until concrete placementprecludes their need, after which they shall be removed.Place concrete continuously without interruption between planned constructionor expansion joints. The delivery rate, placing sequence, and methodsshall be such that fresh concrete is always placed and consolidated againstpreviously placed concrete before initial set has occurred in the previouslyplaced concrete. Do not allow the time between the placement of successivebatches to exceed 30 minutes.During and after placement of concrete, do not damage previously placedconcrete or break the bond between the concrete and reinforcing steel. Keepworkers off fresh concrete. Do not support platforms for workers and equipmentdirectly on reinforcing steel. Once the concrete is set, do not disturbthe forms or reinforcing bars that project from the concrete until it is ofsufficient strength to resist damage.(b) Sequence of placement.(1) Substructures. Do not place loads on finished bents, piers, or abutmentsuntil concrete cylinder tests from the same concrete cured underthe same conditions as the substructure element indicate that all concretehas at least 80 percent of its required 28-day compressive strengt h.(2) Vertical members. For vertical members over 15 feet in height,allow the concrete to set for at least 4 hours before placing concrete forintegral horizontal members. For vertical members less than 15 feet inheight, allow the concrete to set for at least 30 minutes. Do not applyloads from horizontal members until the vertical member has attained itsrequired strength.385