402Structural Concrete

– STRUCTURAL CONCRETE STRUCTURAL CONCRETE

402.1DESCRIPTION

Provide the grades of concrete sp ecified in the Contract Documents. This specification is specific to Structural Concrete. See SECTION 401 for general concrete requirements.

402.2MATERIALS

Provide materials that comply w ith the applicable requirements. General Concrete .................................................................................................... … SECTION 401 Aggregate ............................................................................................................... ….. DIVISION 1100 Admixtures, and Plasticizers ................................................................................. ….. DIVISION 1400 Cement, Fly Ash, Silica Fume, Slag Cement and Blended Supplemental Cementitious........................................................................................................... …. DIVISION 2000 Water ………………………………………………………………. ..................... ….. DIVISION 2400

402.3CONCRETE MIX DESIGN

outlined in SECTION 401 or Appendix A to design structural concrete mixes. Mixes developed using Appendix A must meet permeability requirements of TABLE 402-1.

401.

Cementitious Materials. Unless specified otherwise in the Contract Documents, select the type of portland cement, blended hydraulic cement and indi vidual and blended supplemental cementitious materials according to SECTION 401.

yard.

difference between the air content from concrete sampled before the pump, and concrete sampled after pumping. Make adjustment to the mix to compensate for the pumping of the concrete.

exceeds 8%.

Method) meter may be used for production with random verification by the Volumetric Method. See KT-19 for special requirements when using the Volumetric Method with high cemen titious concretes or mixtures with midrange water reducers or plasticizers.

Concrete Not Placed on Grade.

Placed on Grade.

– STRUCTURAL CONCRETE

or 56-day Rapid Chloride Permeability as per AASHTO T-277 when required . Submit accelerated cure procedures for the Engineer’s approval. The field verification test procedure must be the same test procedure as the mix design approval test.

See SECTION 401.

fume cannot be added to the cementitious materials, add th e loose silica fume to the bo ttom of the stationary drum that is wet, but has no standing water, before adding the dry materials. The Engineer may approve shreddable bags on a performance basis, only when a central batch mixing process is used. If so, add the bags to half of the mixing water and mix before adding cementitious materials, aggregate and remainder of water. Mix silica fume modified concrete for a minimum of 100 mixing revolutions.

subsection 401.3d.(6) for requirements. ASTM C 1567 is not necessary for concrete modified with only Silica Fume.

concrete application. Reject concrete with a slump that limits the workability or placement of the concrete.

allowable slump for the individual type of construction.

slump is less than 8 inches, redose the concrete with admixtures as permitted in subsection 401.3i.

TABLE 402-1: REQUIREMENTS FOR STRUCTURAL CONCRETE Volume of Permeable Voids, maximum Surface Resistivity, minimum Rapid Chloride Permeability, maximum ASTM C-1567 Accelerated Mortar Bar Expansion Use Low Permeability Concrete

Use Moderate Permeability Concrete (MPC) for specified Full Depth Bridge Decks. 11.0% 13.0 kΩ-cm 2000 Coulombs 0.10% @ 16 days Use Standard Permeability Concrete

concrete not specified as Low or Moderate Permeability. 12.0% 9.0 k Ω-cm 3000 Coulombs 0.10% @ 16 days – STRUCTURAL CONCRETE APPENDIX A – NON-MANDATORY INFORMATION GENERAL CONCRETE FOR STRUCTURES AND SILICA FUME MODIFIED CONCRETE CONCRETE FOR STRUCTURES Design concrete for st ructures according to TABLE 402-A1 meeting the applicable requirements for Volume of Permeable Voids, Surface Resistivity or Rapid Chloride Permeability as required in TABLE 402-1. TABLE 402-A1: CONCRETE FOR STRUCTURES Grade of Concrete lb. of Cementitious per yd of Concrete, minimum lb. of Water per lb. of Cementitious, maximum Grade 6.0(**)(***)(****): MA Gradation 700 0.35 Grade 5.0(**)(***)(****): MA Gradation 602 0.35 Grade 4.5(**)(***)(****): MA Gradation 602 0.40 Grade 4.0(**)(***)(****): MA Gradation 602 0.44 Grade 3.5 and 3.0(**): MA Gradation 564 0.46 Grade 2.5(**): MA Gradation 526 0.50 Structural Concrete (*) (**) (***)(****) *Grade as specified in the Contract Documents **Air Entrained meeting subsection 402.3e. ***Aggregate as specified in DIVISION 1100. ****MPC (Moderate Permeability Concrete) Air entrained concrete with a target air of 6.5 ± 1.5 percent. Maximum water to cementitious ratio of 0.50 and a minimum cementitious content of 480 lbs per cubic yard. Maximum limit of lb. of water per lb. of cementitious material includes free water in aggregates, but excludes water of absorption of the aggregates. SILICA FUME MODIFIED CONCRETE When silica fume is selected for use in structural concrete, meet the mix design and production requirements in TABLE 402-A2. Use MA-6 Aggregate Gradation for Bridge Overlay concrete. TABLE 402-A2: SILICA FUME BRIDGE OVERLAY CONCRETE CRITERIA lbs. of Cement per cu. yd. maximum 595 lbs. of Silica Fume per cu. yd., maximum 30 lbs. of water per lbs. of (Cement + Silica Fume), maximum 0.40 Percent of Air by Volume 6.5±1.5 Maximum 28 day Permeable Voids KT-73 9.50% or Minimum 28 day Surface Resistivity KT-79 27.0 kΩ-cm or Maximum 56 day Rapid Chloride Permeability T-277 1000 coulombs