775The SFMC shall utilize a Type F or G admixture to be combined with an air-

722.06 Preparation of the Bridge Floor

722.07 Patching of the Bridge Floor

A vacuum device shall be used to remove all water from the prepared cavities.

722.09 Mixing

722.10 Placing and Finishing

Existing expansion joints shall be maintained throughout the overlayment unless otherwise shown on the plans. A construction dam or bulkhead, equal in thickness to 470 the joint width, shall be installed to the required grade and profile prior to placing the overlay. Screed rails for the finishing machine shall be placed to the required profile, and anchored for stability both vertically and horizontally. Screed rails shall not be treated with a bond breaking compound. The overlay shall be placed only when the ambient temperature is 45°F and rising, unless otherwise approved by the Departme nt in writing. The maximum allowable ambient temperature during placement is 85°F . The overlay shall not be placed if rain is expected within 4 h. Adequate precautions shall be taken to protect freshly placed overlay material from sudden or unexpected rain. Damaged material shall be removed 480 and replaced with no additional payment. A construction dam or bulkhead shall be installed in case of a delay in placement of 1 h or more. During delays of less than 1 h, the end of the placed overlay material shall be protected from drying with layers of wet burlap. After the surface has been cleaned, and immediately before placing the overlay material, the surface shall be thoroughly soaked and covered with plastic sheeting for a period of 1 h. The surface shall not be a llowed to dry before placing the overlay material and there shall be no standing water at the time of placement. The surface shall then be thoroughly and evenly coated with a brush applied bond coat of overlay 490 concrete, except a bond coat shall not be applied to surfaces wh ere the removal was performed by hydrode molition. The prog ress of the bond coat application shall be controlled to ensure that the bond coat does not dry before the overlay is placed to the required grade. Aggregate segregated in the brush application of the bond coat shall be removed before the overlay is placed. Surface irregularities shall be filled to approximately three-quarters of their depth sufficiently ahead of the overlay operation to allow the material to stiffen and resist rolling back during the finishing. Following the bond coat application and partial filling of any surface irregularities, the concrete overlay shall be placed to an elevation approximately 1/2 500 in. above final grade. The mix shall then be consolidated and machine finished to the required grade. The machine finishing shall be to within 12 in. of the curb line or coping line unless otherwise directed. Supplemental hand finishing with a wood float shall be performed as needed to produc e the required tight and uniform surface. 722.10 The finishing machine shall be self-propelled and capable of positively controlled forward and reverse motion. The machine shall be equipped with at least two finishing devices. The first finishing device shall be a vibrating mechanism, such as a vibrating pan, for consolidating the deposited mix. The vibrating pan shall be metal and of sufficient dimensions to ensure proper consolidation. The second finishing device 510 shall be either a rotating cylindrical drum, at least 45 in. in length, or a vibrating oscillating metal faced screed of 4 in. minimum in width. The vertical position of the finishing devices shall be positively controlled and the devices shall be raised clear of the finished surface when the machine is operated in the reverse direction. The vibration frequency of any vibrating finishing device shall be variable, with positive control between 3,000 and 6,000 vibrations per minute. Alternate finishing machines may be considered for approval subject to a written request. Screed rails and construction dams shall be separated from the newly finished overlay by passing a pointing trowel along the rail-to-overlay and dam-to-overlay 520 interfaces after the overlay has sufficiently set such that it does not flow back. This trowel cut shall be made for the entire length and depth of the rail or dam. The rails may be removed any time after the overlay ha s initially set. Adequate precautions shall be taken during and after the rail removal to protect the edge of the new overlay from damage. Protection shall be provided to prevent rapid drying of concrete. The rate of water evaporation shall be determined both prior to placement based on forecasted conditions and during placement based on actual conditions in accordance with ACI 308, section 5.2.1 or the following equation: 530 E = (T c2.5 - rT a2.5)(1 + 0.4V) x 10-6 where: E = Evaporation rate, lb/sq ft/h T c = Concrete mix temperature, °F Ta = Ambient temperature, °F r = (Percent of Relative Humidity)/100 V = Wind velocity, mph. Measurement of T a, r, and V shall be obtained from readings made by the local weather bureau or the Contractor's measur ements made on site. Measurement of T c shall be determined from the concrete on site at the point of placement. Fog misting shall be performed after the finishing operation and prior to the wet cure, where the evaporation rate exceeds or is expected to exceed 0.05 lb/sq ft/h. Fog misting shall 540 keep the environment above the concrete su rface at high humidity to protect against plastic shrinkage cracks and shall not be used to apply water directly to the surface to facilitate finishing. Evaporation retardants shall not be substituted for fog misting where the evaporation rate exceeds 0.05 lb/sq ft/h. 722.10 784 An evaporation retardant shall be applie d in a fine mist immediately after the finishing is complete to ensure that the surface remains wet until covered. The evaporation retardant shall be used as such and not as a finishing aid. These products consist primarily of water and excessive amounts of evaporation retardant shall not be applied and the product shall not be worked into the overlay surface. Evaporation 550 retardant shall only be used on SFMC overlay s. Evaporation retardant shall not be used in any other applications.

722.11 Texturing

The overlay surface shall be textured with a double thickness burlap drag or a minimum 4 ft wide turf dr ag immediately following th e placement of the overlay material. Areas where the texture is disturbed by other finishing operations shall be immediately restored to a burlap drag finish. Grooving or tining in the plastic concrete of the concrete overlay will not be 560 allowed. Longitudinal grooving shall not commence until the curing requirements have been met in accordance with 722.12. Grooves shall be cut into the hardened concrete surfaces parallel to the centerlin e using a mechanical cutting device. For curved bridges, grooves shall be cut along the curve chord within the spans. Grooving shall be done before traffic is allowed on the surface except as follows. The Contractor shall have the option of cutting the longitudinal grooves at the end of each phase of construction or waiting until all phases have been completed. If the Contractor elects to delay the grooving process until completion of all phases, the concrete overlay surface for any phase opened to traffic shall receive an interim coarse 570 broom finish during placement. The completion of the grooving process shall be within 30 days of completion of the last phase of construction. Any additional maintenance of traffic operations required for the grooving process shall be included in the cost of Maintaining Traffic. The interim broom finish shall not be allo wed as a surface texture when opened to traffic over a winter season. If the coarse broom texture is present and the Contractor is not in a position to finish all phases of the project, longitudinal grooving shall be placed into the hardened concrete in order to establish an acceptable driving surface texture for the winter season. 580 Each groove shall be 1/8 in. ±1/64 in. in width, 3/16 in. ±1/16 in. in depth. The grooves shall be uniformly spaced at 3/4 in. intervals measured from the center of groove to center of groove. Grooving shall not be within the area approximately 2 ft adjacent to the curbs or railings. The grooving shall not be cut closer than 3 in. nor further than 6 in. from any construction joint running parallel to the grooving. The grooving shall not be cut within 6 in. of deck drains, curbs, or expansion joints. If the bridge has a variable width traffic lane, the grooving shall remain parallel to the centerline of the main roadway. Any staggering of the groove terminations to accommodate the variable width shall be with in the shoulders. Stair stepped ends in 590 grooving will be allowed for skewed bridge decks. When a new reinforced concrete 722.11 785 approach slab is placed adjacent to the overlay, the grooving shall extend across the reinforced concrete approach slab. Grooving shall terminate approximately 6 in. from the interface with th e roadway pavement. The grooving machine shall contain diamond blades mounted on a multi-blade arbor on a self-propelled machine built for grooving hardened concrete surfaces. The grooving machine shall have a depth control device that detects variations in the deck surface and adjusts the cutting head height to maintain a specified depth of the grooves. The grooving machine shall have a guide device to control multi-pass alignment. 600 The Contractor shall submit a wastewater control and disposal plan for approval seven days prior to commencing grooving ac tivities. The wastewater control and disposal plan shall detail how all wastewater generated by the grooving activities shall be contained, tested for pH, stored and transported to a disposal facility in accordance with 202. Cleaning of the grooving debris and slurry shall be performed with a vacuum system equipped with fugitive dust control devices and be capable of removing wet debris and water in the same pass. The vacuum equipment shall be capable of washing 610 the deck with pressurized water during the vacuum operation to dislodge all debris and slurry from the bridge deck surface. Debris and slurry shall not be allowed to dry prior to vacuuming. 722.12 Curing When fly ash is used, the requirement for additional wet or dry curing time shall be determined based on the relative initial, and final time of set and a comparison of strength versus age using control concrete strengths at conventional cure period ages as the reference. The additional curing requirements shall be as approved by the Engineer. 620 For LMC overlays the minimum curing period shall be 48 h of wet cure followed by 48 h of dry cure. An LMC overlaid bridge deck may be opened to traffic during the dry curing duration when the compressive strength of cylinders is 4,000 psi or greater. For SFMC overlays the minimum curing period shall be seven calendar days consisting of 120 h of wet cure followed by 48 h dry cure. The deck shall remain completely covered during the dry cure period. An SFMC overlaid bridge deck may be opened to traffic after the dry cure period when the compressive strength of cylinders is 4,500 psi or greater. 630 For LMC-VE concrete overlays the minimum curing period shall be 3 h of wet cure. An LMC-VE overlaid bridge deck may be opened to traffic after the wet curing period when the compressive strength of cylinders is a minimum of 2,500 psi. The wet cure period for all overlay types is not controlled by strength and shall not be reduced. Membrane forming curing compound shall not be used to cure the 722.12 786 bridge deck overlay. All cylinders shall be 6 in. by 12 in. and compressive strength shall be determined from the average of a minimum of two cylinders. For LMC and SFMC, cylinders shall be cast and cured in accordance with 702.24. For LMC-VE 640 cylinders shall be cast and field cured at the jobsite under the same conditions as the LMC-VE overlay. The plastic film which forms on the surf ace of the overlay shall be protected from shrinkage cracking with a single layer of well drained wet burlap. This layer of wet burlap shall be placed as soon as the ove rlay surface will support it without deformation. The entire surface shall be covered with plastic sheeting and maintained in a saturated wet condition during the wet cure period. A network of soaker hoses shall be used under the plastic sheeting during the wet cure period for LMC and silica fume overlays. 650 When the ambient temperature falls below 50°F during either the wet or dry curing periods, the time that the temperature is below 50°F shall not be considered as part of the total curing period. When there is sufficient rain to wet the surface of the overlay for 1 h or more during the dry cure period, this number of hours shall not be considered as part of the dry cure period. Immediately upon the start of the dry cure period or opening to traffic, the surface shall be checked for cracks. Upon request, the Contractor shall flood the deck with water to facilitate inspectio n for cracks and distress. Where cracks exist, a thorough 660 investigation will be conducted prior to sealing cracks. Cores may be required to determine the actual crack depth. Surface crac ks not exceeding 3/8 in. in depth shall be sealed with a PCC Sealer/Healer followed by an application of an approved sand. Cracks exceeding 3/8 in. in depth shall not be sealed at this time. Corrective procedures for repairing cracks exceeding 3/8 in. in depth will be determined after further investigation which may include additional cores. The Department’s Division of Materials and Tests will be contacted and the Engineer will determine the method of repair including possible removal. Where the area of shallow cracking exceeds 5% of the deck area, then the method 670 of repair shall be the same as for cracks exceeding 3/8 in. The shallow crack area will be calculated by multiplying the total combined linear feet of all cracks less than 3/8 in. deep by a tributary width of 1 lft. The percentage of deck area will be the shallow crack area divided by the total deck area and multiplied by 100. Where it is determined by sounding or coring that adequate bonding between the overlay and the bridge deck has not been attained, the deficient areas shall be removed and replaced as directed.

722.13 Calibration of Continuous Mixers 680

722.10 Machine finishing shall be required when directed. 800