721 SECTION 679 OVERLAYING OF PORTLAND CEMENT CONCRETE BRIDGE DECKS
679.1 -DESCRIPTION : The work shall consist of furnishing and placing a specialized concrete overlay to a designated grade line. Unless otherwise indicated on the plans, the Contractor may place any one of the specialized overlays allowed by the terms of this specification. Only one type of overlay will be allowed on any one structure.
679.1.1 -Other Work: The following work, as required by the contract plans, may also be performed under the terms of this section:
in the plans.)
679.1.2 -Definitions: 679.1.2.1 -Specialized Concrete Overlay: Two types of specialized concrete overlay are permitted as follows: 1) Latex Modified Concrete: A Portland cement concrete to which an approved styrene butadiene latex admixture has been added. 2) Silica Fume Concrete: A Portland cement concrete to which an approved silica fume admixture has been added.
679.1.2.2 -Slab Reconstruction Concrete: Slab reconstruction concrete is that concrete placed completely around exposed reinforcing bars.
679.1.2.3 -Curing Hour: A curing hour is any hour, beginning with the hour of placement, during which the temperature of the concrete surface remains at, or above, 50° F as measured by a recording thermometer.
679.1.2.4 -Curing Temperature: This is the air temperature at the concrete surface, or the air temperature between the concrete surface and its protective covering.
679.2 -MATERIALS : 679.2.1 -General: Materials used in the manufacture of sp ecialized concrete overlays shall meet the requirements specified in Section 601.2 of the Specifications and as required herein.
679.2.1.1 -Fine Aggregate: Fine aggregate shall be silica sand meeting the requirements of Sections 702.1.2 through 702.1.5 a nd 702.6 of the Specifications.
679.2.1.2 -Coarse Aggregate: Coarse aggregate shall be AASHTO Size No. 8 crushed stone or gravel conforming to Section 703 of the Specifications.