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8 FIGURE 4 Schematic of possible components of liquid systems. SPECIFICATIONS AND STANDARDS Tensile strength in machine direction per ASTM D882 Method A of 50 lb/in. for rubberized asphalt and 40 lb/ AASHTO Specifications in. for modified bitumen. Percentage elongation at breach in machine direction Waterproofing of concrete bridge decks is addressed as part per ASTM D882 Method A of 15% for rubberized of Section 21 of the AASHTO LRFD Bridge Construction asphalt and 10% for bitumen at 73.4F. Specifications (9). Waterproofing is defined as either a con- Pliability per ASTM D146 based on 180-degree bend structed-in-place asphalt membrane system or a preformed over a 4-in. diameter mandrel at 10F with no cracks. membrane system, both of which include appropriate prim- Minimum thickness of 65 mils for rubberized asphalt ing materials and, when required, protective coverings. and 70 mils for modified bitumen. Softening point per ASTM D36 of 165F for rubber- An asphalt membrane system consists of a coat of primer ized asphalt bitumen and 210F for modified bitumen. applied to the prepared surface, a firmly bonded membrane composed of two layers of saturated fabric, and three mop- All materials are required to be tested before shipment. pings of waterproofing asphalt with a protective cover when required. Materials listed for use with asphalt membrane For roadway surfaces of bridge decks, the protective cover systems are required to conform to one or more of the fol- to the waterproofing system is required to consist of a layer of lowing ASTM specifications published by ASTM Interna- special asphalt concrete as specified in the contract documents. tional, West Conshohocken, Pennsylvania: The AASHTO specifications require that all concrete sur- D41 Standard Specification for Asphalt Primer Used in faces to be waterproofed shall be reasonably smooth and free Roofing, Dampproofing, and Waterproofing (used for of foreign matter, projections, or holes. The surface shall be the primer) dry and have a temperature not less than 35F or that recom- D173 Standard Specification for Bitumen-Saturated mended by the manufacturer, unless otherwise approved by the Cotton Fabrics Used in Roofing Waterproofing (used engineer. The specifications contain specific detailed instruc- for the reinforcing fabric) tions for the installation of asphalt membrane waterproofing D449 Standard Specification for Asphalt Used in systems and preformed membrane waterproofing systems. Dampproofing and Waterproofing (used for the asphalt) D3515 Standard Specifications for Woven Glass Fabric State Specifications Treated with Asphalt (used for the reinforcing fabric). State specifications for waterproofing membranes are simi- According to the AASHTO specifications, a pre- lar to the AASHTO specifications. Table 2 reviews the dif- formed membrane system consists of a primer applied to ferences identified in the state specifications. the prepared surface, a single layer of adhering preformed membrane sheet, and a protective cover when required. Pre- Some states specify more details than the AASHTO speci- formed membrane sheets consist of either the rubberized fications; others specify fewer. Some of the states with fewer asphalt system or the modified bitumen type. Both types are details rely heavily on the manufacturer's recommended instal- required by the specifications to conform to minimum val- lation procedures and the state's approved products list. Some ues for the following properties: state specifications are very specific about the generic type of

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9 TABLE 2 Based on the results of the survey and review of state SUMMARY OF STATE SPECIFICATION REQUIREMENTS specifications, the following is a summary of practices that Property AASHTO States are followed: Minimum thickness for rubberized 65 50 and 60 asphalt, mil. 1. Pre-installation Minimum thickness for modified bitu- 70 50 and 60 men, mil. Require a manufacturer's representative to be pres- Minimum deck or air temperature, F 35 40, 45, and 50 ent when work is performed. One state's specifi- cations require that the representative be readily Puncture resistance, lb -- 40 and 200 identified with a photo ID badge. Maximum permeance, perms -- 0.10 Require that all work be performed by the manu- Minimum longitudinal overlap, in. 2.0 2.0, 2.5, 3.0, 4.0, facturer's certified personnel. It is important that and 6.0 the certified personnel and the manufacturer's rep- -- = Not specified. resentative not be the same person. materials that may be used. For example, the Massachusetts 2. Surface Preparation specifications allow the use of three types of membranes: Ensure that the concrete surface is free of protru- 1. Coal tar emulsion reinforced with two plies of coated sions and rough edges. glass fabric Use abrasive blasting to remove all contamination from the deck, including all material from the pre- 2. Hot applied rubberized asphalt membrane vious membrane. Do not use water to clean the deck, as the surface 3. Preformed sheet systems, either reinforced rubber- must be dry before the primer is applied. ized asphalt or reinforced tar and resin. Clean surface with brooms, vacuum, or compressed air to remove all loose material before applying the System 2 is not used on grades steeper than 3%, and Sys- membrane system. Some specifications require tem 3 is the only system acceptable for butted deck beams inspection and approval by the engineer before and adjacent box beams. For the two plies of coated glass priming. Other states delegate the responsibility to fabric, the first ply is laid transverse to the center line of the manufacturer's representative. the bridge and the second layer parallel to the center line. Reinforce or repair cracks before placing the The bituminous concrete protective course is to be applied membrane. within 24 hours after the membrane is installed. 3. Installation of Waterproofing System Virginia DOT specifications permit five systems: Specify a minimum deck and/or air temperature 1. System A--A primer and prefabricated membrane before applying the membrane. Specified values consisting of a laminate formed with suitably plasti- range from 35F to 50F. For heat-welded mem- cized coal tar and reinforced with nonwoven synthetic branes, one state requires the substrate temperature fibers or glass fibers. to be at least 5F above the dew point. Specify a dry deck and application only in dry 2. System B--A primer, mastic, and prefabricated mem- weather. One state specifies a surface moisture con- brane consisting of a laminate formed with rubberized tent of less than 6% and requires the contractor to asphalt and reinforced with synthetic fibers or mesh. have a calibrated electronic surface moisture meter. Use a primer to enhance the bond between the con- 3. System C--A primer and prefabricated membrane crete deck and the membrane, where required by consisting of a laminate formed with suitably plasti- the specifications or the manufacturer. cized asphalt, reinforced with open-weave fiberglass Install reinforcing membrane over cold joints and mesh and having a thin polyester top surface film. cracks in the concrete deck. Make a complete seal with the curb up to the depth 4. System D--A hot-poured liquid elastomeric mem- of the asphaltic concrete overlay. brane with protective covering. Begin placement of preformed membranes on the low point of the deck and provide adequate lap 5. System E--A surface conditioner and a hot-applied between adjacent strips. This permits water to rubberized asphalt membrane with protective covering. drain without accumulating against the seams. The

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10 specified minimum overlap for longitudinal seams 4. Quality Control ranges from 2 to 6 in. Stagger membrane overlaps in the transverse direc- Conduct adhesion bond testing for spray-applied tion so that transverse seams do not line up. One membranes. state requires that end laps be in the direction of the Perform leak testing after the overlay is placed. paving operation. The easiest time to do this is during a rainstorm. Repair any blisters that appear in the membrane However, the United States does not have a stan- before the overlay is placed, per the manufacturer's dard test procedure for leak testing. recommendations. Prohibit or minimize traffic on the membrane and ASTM Standards allow only rubber-tired vehicles until the overlay is placed, or use protection boards. The AASHTO and state specifications reference numerous Specify a minimum and maximum time between ASTM standards for material specifications and test meth- membrane application and the first layer of over- ods. Table 3 lists the relevant standards identified from the lay placement. The minimum time allows for the survey and review of state specifications during the develop- membrane to cure properly and depends on the ment of this synthesis. manufacturer's recommendations. The maximum time reduces the length of time that the membrane ASTM D4071 covers liquid applied, preformed, and built- is exposed to potential damage. Specified values up membrane systems and their application, including the range from 1 to 5 days. bituminous wearing course. The practice provides a guide Use a tack coat to enhance the bond between the for the factors to be considered prior to waterproofing bridge membrane and the overlay. decks with a membrane system. Guidance for the specifi- TABLE 3 ASTM STANDARDS RELATED TO WATERPROOFING MEMBRANES ASTM Designation Title D5 Standard Test Method for Penetration of Bituminous Materials D36/D36M Standard Test Method for Softening Point of Bitumen (Ring-and-Ball Apparatus) D41/D41M Standard Specification for Asphalt Primer Used in Roofing, Dampproofing, and Waterproofing D146 Standard Test Methods for Sampling and Testing Bitumen-Saturated Felts and Woven Fabrics for Roofing and Waterproofing D173 Standard Specification for Bitumen-Saturated Cotton Fabrics Used in Roofing and Waterproofing D449 Standard Specification for Asphalt Used in Dampproofing and Waterproofing D517 Standard Specification for Asphalt Plank D882 Standard Test Method for Tensile Properties of Thin Plastic Sheeting D1228 Methods of Testing Asphalt Insulating Siding Surfaced with Mineral Granules (Withdrawn 1982) Withdrawn Standard D1668 Standard Specification for Glass Fabrics (Woven and Treated) for Roofing and Waterproofing D1777 Standard Test Method for Thickness of Textile Materials D3236 Standard Test Method for Apparent Viscosity of Hot Melt Adhesives and Coating Materials D3515 Standard Specification for Hot-Mixed, Hot-Laid Bituminous Paving Mixtures Historical Standard D4071 Standard Practice for Use of Portland Cement Concrete Bridge Deck Water Barrier Membrane System D4541 Standard Test Method for Pull-Off Strength of Coatings Using Portable Adhesion Testers D4632 Standard Test Method for Grab Breaking Load and Elongation of Geotextiles D4787 Standard Practice for Continuity Verification of Liquid or Sheet Linings Applied to Concrete Substrates D6153 Standard Specification for Materials for Bridge Deck Waterproofing Membrane Systems D6690 Standard Specification for Joint and Crack Sealants, Hot Applied, for Concrete and Asphalt Pavements E96/E96M Standard Test Methods for Water Vapor Transmission of Materials E154 Standard Test Method for Water Vapor Retarders Used in Contact with Earth Under Concrete Slabs, on Walls, or as Ground Cover

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11 cation of materials, application of membrane systems, and Canadian specifications generally require the use of placement of the bituminous wearing surface is provided. hot applied rubberized asphalt for waterproofing mem- The standard is more of a checklist of items to address than branes, whereas U.S. specifications permit other types a standard specification that spells out all the details. of membranes. Some Canadian specifications require rubber mem- Canadian Specifications branes or reinforcing fabric to be installed over cracks and joints before the asphalt membrane is applied, as The specifications from six Canadian provinces were shown in Figure 5. reviewed for this synthesis. In general, the different speci- Most Canadian specifications require the use of protec- fications contain similar provisions although the degree of tion board on top of the waterproofing membrane. detail varies. The Ontario provincial specification OPSS 914, Construction Specifications for Waterproofing Bridge United Kingdom Practices Decks with Hot Applied Asphalt Membranes (10 ) provides the most details, including separate specifications for the In 1999, the United Kingdom Department for Transport hot applied rubberized asphalt membrane and the protec- (UKDOT) formally issued BD47/99, Waterproofing and tion board. Surfacing of Concrete Bridge Decks (11). This standard gives the requirements for the design, materials, and work- The U.S. and Canadian specifications have three major manship for the waterproofing and surfacing of concrete differences. decks for highway bridges. It specifies that decks of high- FIGURE 5 Waterproofing over joints and cracks (150 mm = 6 in.) [Source : Alberta Transportation].