680 SECTION 709 – PORTLAND CEMENT CONCRETE SEALERS
709.01 Description
This work shall consist of cleaning the concrete surface by sandblasting and applying a concrete sealer in accordance with 105.03. Surfaces to be sealed with PCC sealers shall be given a finish in accordan ce with 702.21. Where existing concrete or bridge decks are to be sealed, their surfaces shall be sandblasted to remove all foreign materials. MATERIALS 10
709.02 Materials Materials shall be in acco rdance with the following:
Non-Epoxy PCC Sealers .................................................... 909.10 CONSTRUCTION REQUIREMENTS
709.03 General Requirements Concrete surfaces shall be 28 days or older prior to application. The concrete 20
surface shall be allowed to dry at least 48 h immediately prior to s ealing. Sealer shall be applied only when the concrete surface, sealer, and ambient temperatures are all between 40°F and 100°F. The sealer shall be applied at the manufacturer’s specified application rate and shall not exceed the maximum rate stated on the QPL of Non- Epoxy Portland Cement Concrete Sealers. Spray applications shall be accomplished using low pressure, non-atomizing spray equipment adjusted to the wet spray condition, approximately 15 psi. The sealer sh all be applied to vertical surfaces such that the spray pattern will be 6 to 8 in. wide and all surfaces shall achieve a uniform coverage. Horizontal surfaces shall be comp letely flooded. The sealer shall not be applied when wind conditions may cause overspray. Sealer shall not be applied in rain 30 or when rain is expected to occur within 2 h after completing the sealing application.
709.04 Surface Preparation The surface to be sealed shall be thorou ghly cleaned of all fo reign materials by
sandblasting if the surface is a bridge deck or older existing concrete, or by air blasting for all other surfaces, just prior to sealing. The air compressor shall be equipped with suitable separators, traps, or filters which remove water, oil, grease, or other substances from the air lines. If rain sufficient to uniformly wet the surface occurs after the cleaning operations and prior to the sealing, the surface to be sealed shall be re-sandblasted or re-airblasted. 40 The concrete to be sealed shall be cu red as stated on the QPL of Non-Epoxy Portland Cement Concrete Sealers prior to sealer application.
709.05 Sealer Application The concrete surface to be sealed shall be completely cleaned and shall be dry and 709.01
681 dust free prior to the application of concrete sealer. The concrete sealer shall be applied in a crisscross pattern and should any flat or dry spots appear, more sealer shall be applied. However, there shall be no puddling of material on the surface. The sealed surface shall be allowed to cure in accordance with the manufacturer’s 50 recommendations. No vehicular traffic will be allowed on the sealed surface during the curing time. A qualified technical representative of the manufacturer may be required to be on the job the first day the sealer is used. It shall be this represen tative’s responsibility to instruct the workers in proper mixing, application technique, and safety precautions.
a.Non-Epoxy PCC Sealers The sealer selected for use shall be applied at the application rate specified on the QPL of Non-Epoxy Portland Cement Concrete Sealers. The sealer shall be applied 60 without dilution or alteration. Sealers which are applied by spraying shall be sprayed onto the concrete surface using low pressure spray equipment with a sufficient number of passes to achieve the minimum application rate and a uniform coverage. The low-pressure spray apparatus shall have a 15 psi maximum nozzle pressure with a course fan spray, such as a garden, form oil, horticulture, or other low pressure sprayer. The spray equipment tanks and hoses shall be thoroughly clean, free of foreign matter, oil, residue, and water prior to use. Sealers shal l be selected from the QPL of Non-Epoxy Portland Cement Concrete Sealers and shall be spread to achieve uniform coverage. If roller spreading is required, a clean new roller shall be used for each application sequence. If brooming is specified, a clean, stif f-bristled broom shall be used to spread 70 and work the sealer into the concrete surface.
b.Clear Sealers Clear sealers shall be used on all verti cal wall surfaces including, but not limited to concrete bridge railing, barrier wall, and exterior concrete bridge beams when sealing is specified for these items. Clear sealers will be those identified on the QPL of Non-Epoxy Portland Cement Concrete Sealers.
c.Alternate to Concrete Sealers In lieu of concrete surface sealing for concrete barrier wall, terminal joint lugs, 80 pier and bent caps, bridge railing, and bridge railing transitions, an alternate concrete mix design may be used. The concrete mix design shall be as specified, except either 3% silica fume by weight of cementitious material shall be added to the mix design or 30% slag cement substitution based on the required cement content shall be incorporated into the mix. The substitution of slag cement shall be in accordance with 702.05. A water-reducing admixture or a water-reducing retarding admixture shall be used in the mix design, and the amount of water added shall be adjusted accordingly. The use of these admixtures shall be in accordance with 702.05. 90 709.05 682 When one of these alternate concrete mix designs are used in lieu of a concrete surface sealer, a finish in accordance with 702.21 will be required.
709.06 Safety Precautions Precautions shall be taken to protect workers from the hazards of these materials. Solvents in some of the seal ers are flammable. All necessary precautions shall be taken
pertaining to the handling and potential overspray of these concrete sealers.
709.07 Method of Measurement 100
Since payment will be made in a lump sum, only those measurements necessary to verify application rates will be made. 709.08 Basis of Payment The accepted quantities of this work will be paid for at the contract lump sum price for surface seal. If an alternate concrete mix design in accordance with 709.05(c) is used in lieu of concrete surface sealing or portions thereof, it will be paid for as surface seal. 110 Payment will be made under: Pay Item Pay Unit Symbol Surface Seal ............................................................................... LS The cost of all materials, labor, equi pment, and necessary incidentals shall be included in the cost of this work. 120
Source: Indiana Standard Specifications, 2024 Edition. Pages 8–11 of 1,248.