655 Expansion joints shall be constructed as shown on the plans and the material shall be in accordance with 906.01.
704.05 Finishing Concrete Concrete shall be placed and spread to the approximate contour for the full width being placed. The concrete may then be c onsolidated using mechanical internal
vibrators in accordance with applicable provisions of 702.20(c). Vibrators shall not be 70 used to spread or move the concrete horizontally to the extent that they cause segregation. Excessive vibration shall be avoided. The use of a self-propelled finishing machine shall be used on all structures when either a new floor or an overlay is placed. C oncrete for the full width of all traffic lanes shall then be struck off to proper profile grade and cross-section by an approved, self-propelled, oscillating, finishing machine. The finishing machine may be for traffic lane widths or full width of the structure when approved. Manually operated strike-off may be used on areas outside of the width of traffic lanes or where required construction joints limit the length of deck pours to 60 ft or less. 80 The finishing machine shall be in accord ance with the applicable requirements of 508.04(b) except it shall have a minimum of one reciprocating non-vibrating screed. The weight of the machine shall not cause undue deflection of the bridge members or falsework. The machine shall travel on steel rails, pipe, or other approved grade control, which shall be adequately supported by adjustable support securely fastened in place at spacing sufficiently close to prevent any appreciable deflection of the screed. Welding of supports to structural bridge members will not be allowed. Prior to the 90 placing of concrete, rails for the machine su pport shall be set to correct elevations shown on the plans or as approved. Rails shall extend a sufficient distance beyond the area to be placed so that the machine clear s all finishing operations. The screed or strike-off beam shall be made of metal or the bottom shall be metal-clad. The bottom of the screed or strike-off shall be adjusted to the true cross-section of the floor surface. The machine shall make only the number of passes over the slab as required to obtain a uniform surface free of voids and reasonably true to the planned profiles and cross-section. Any necessary hand finishing after removing the rails and rail supports shall be 100 accomplished promptly to fill any depressions and remove any roughness of the surface in the area from which the supports are removed. The longitudinal mechanical screeding method may be used when approved. A mechanical bridge deck finishing machine using a rotating cylinder setting approximately parallel to the longitudinal movement of the machine and operating transversely may be used for screeding the bridge deck, when approved. When a finishing machine is not used or required, the concrete shall be struck-off to the specified grade as soon as the concre te is placed and consolidated, by means of 704.05 656 a steel template or other satisfactory meta l clad implement havi ng a minimum width 110 of 9 in. or greater. For all methods of striking off the surface, an excess of concrete shall always be kept in front of the cutting edge. The strike-off shall go over the entire area only for the number of times necessary to produce the required profile and cross-section. The strike-off process shall be in accordance wi th 508.04 except a vibrator on the strike- off will not be required. Immediately after screeding to the requ ired cross-section, the surface shall be checked with a long-handled 10 ft straightedge, of light construction, laid parallel to 120 the centerline at intervals of no more than 2 ft transversely and 5 ft longitudinally. In case it is impracticable to operate the straightedge otherwise, it shall be operated from a footbridge or from bridges on the floor. All high spots shall be removed and depressions filled with fresh concrete and then leveled with a float having a blade approximately 5 ft long and 8 in. wide. Floating and manipulating concrete to fill depressions shall be held to a minimum. Checking and leveling shall continue until the surface has the required contour and is free of voids. The application of water to the surface for the purpose of lubricating the floats and straightedges may be used only when absolutely necessary and shall be held to a minimum. The water applied for this purpose shall be limited to such quantity as may be applied by heavy fogging as 130 approved. As soon as the water begins to leave, th e surface shall be given a final check with the lightweight straightedge. The required cross-section shall be preserved. The final surface shall be free from porous spots caused by the disturbance of coarse aggregate particles during the final checking and brooming. If a new bridge deck is to be overlaid with latex modified concrete, the surface of such deck shall be heavily broom textured to provide maximum bonding of the overlay material. Just before the concrete has taken the initia l set, the ends of slabs, exposed edges, 140 and transverse construction joints shall be rounded to a 1/4 in. radius. Longitudinal construction joints shall not be edged unless otherwise directed. Smoothness shall be in accordance with 502.20. If, after the above requirements have been met, portions of the floor are not entirely satisfactory, the removal and replacement of such portions may be ordered to secure a satisfactory floor. Such removal and replacement shall be done with no additional payment. After final smoothness checking, the surface shall be longitudinally grooved in accordance with 722.11. 150
704.06 Curing
Floor slabs shall be cured in accordan ce with 702.22(a)1. Where it has been determined that a surface treatment to preven t scaling is to be used, the Engineer may prohibit the use of the membrane forming curing compound on any part of the superstructure. All vertical surfaces with exposed reinforcement shall be cured in 704.06 657 accordance with 702.22. The floor shall be protected from pedest rian and vehicular traffic. If walking is necessary, the surf ace shall be timber laid on a double burlap cushion or approved equivalent. Opening to traffic shall be in accordance with the applicable provisions of 702.24. 704.07 Method of Measurement Concrete floor slab will be measured by the cubic yard in accordance with 702.27. However, no allowance will be made for variations in beam fillet depths, coping depths, or diaphragm depths, which are deemed necessary due to the beam camber, as constructed, which varies from that shown on the plans. Reinforcing bars will be measured in accordance with 703.07. Casti ngs will be measured in accordance with
702.27 170
Longitudinal grooving will be meas ured in accordance with 722.15.
704.08 Basis of Payment The accepted quantities of concrete floor slab will be paid for at the contract unit price per cubic yard for concrete, C, superstructure. Reinforcing bars will be paid for
in accordance with 703.08. Castings will be paid for in accordance with 702.28. Longitudinal grooving will be paid for in accordance with 722.16. Payment will be made under: 180 Pay Item Pay Unit Symbol Concrete, C, Superstructure ....................................................... CYS The cost of forms, curing, finishing, preformed expansion joints within structure limits, slab bridge floor drains, and necessary incidentals shall be included in the cost of the pay items.