Attachment to C-408/94-235
October 13, 1999
COMMONWEALTH OF PENNSYLVANIA
Department of Transportation
Supplementing the Specifications
Publication 408 dated 1994
SECTION 680.1 DESCRIPTION
This work is the furnishing and placement of adhesive preformed membrane waterproofing systems to concrete or other surfaces as indicated.
SECTION 680.2 MATERIAL -
Unless specified or shown on the plans, select from the waterproofing systems listed in Bulletin 15.
(a) Adhesives, Conditioners, Primers, Mastics, Two Part Liquid Urethane Membranes and Sealing Tapes.
As recommended for use with the respective preformed membrane sheet materials. Contact the membrane manufacturer or their representative for instructions.
(b) Adhesive-backed Preformed Membrane Sheet.
Furnish Adhesive-Backed Preformed Membrane Sheet consisting of a sheet of rubberized asphalt or polymer modified bitumen permanently applied to a polyethylene film, or reinforced with a stitch-bonded polyester/polypropylene fabric, or reinforced with a fiberglass mesh and meeting the minimum requirements specified in Table A.
(c) Protective Covers.
Provide a 1/8-inch thick, asphalt protective board or 65 pound roofing material without mica coating or approved equal that furnishes equivalent protection to the membrane from being cut, scratched, or otherwise damaged from the backfill or equipment.
For bridge deck surfaces, the bituminous overlay is the protective cover.
(d) Bonding Material.
Section 460 and as recommended by the manufacturer.
(e) Manufacturer Technical Representative.
Have a trained Manufacturer Technical Representative present during every phase of the application, unless a factory trained licensed installer, as indicated by written approval from the material supplier, applies the waterproofing system. Manufacturer Technical Representative will provide training and technical assistance on surface preparation, equipment, mixing of components, type and method of application, and finish.
Certify each shipment as specified in Section 106.03(b)3. Visibly label all shipments on the membranes or containers with the manufacturer’s name, membrane trade name, lot number, and material quantity.
Adhesive-backed Preformed Membrane Sheet Minimum Requirements
Preformed Membrane Sheets
For Bridge Deck Surfaces
For Surfaces Other Than Bridge Decks
Modified Bitumen Type
Modified Bitumen Type
Tensile Strength, lbs/in
% Elongation at Break, (min) (3)(4)
Softening Point, OF (minimum)
Puncture Resistance, lbs (min)
(1) Breaking factor in machine direction. (4) Machine direction.
(2) Method A, 1" wide strip with 4" minimum (5) 180-degree bend over a one-
inch mandrel at -15F.
initial separation & 4" gage length at 2"
per minute. Average 5 samples. (6) Total thickness of preformed
membrane sheet and polyethylene
film or fabric
(3) At 73.4F
SECTION 680.3 CONSTRUCTION -
(a) Limitation of Operations.
Apply waterproofing only when protective covering or bituminous overlay can also be placed within a time that assures that the membrane will not be damaged by personnel, equipment, exposure to weathering, or from any other cause.
Do not install any part of a waterproofing system in wet, humid, or foggy weather conditions, or when the ambient or concrete surface temperature is below 50F, unless recommended by the manufacturer and authorized in writing by the Engineer. Apply the primer and waterproofing membrane only when the concrete surfaces are completely dry.
(b) Surface Preparation.
Prepare the surface to be waterproofed to a condition free from holes or projections, which might puncture or otherwise damage the membrane. Round (outside) or chamfer (inside) all sharp corners to be covered.
Thoroughly clean all concrete surfaces that are to be waterproofed. Remove any excess laitance, oil, concrete curing compounds, previous membrane treatments, and other foreign materials by sandblasting. Remove all dirt, dust, loose or unsound concrete, and other extraneous material by vacuuming or blowing with compressed air.
Use a scratch coat of asphalt as a leveling course on decks that have been milled and lack a surface that is acceptable to receive a membrane system. Asphalt paving less than one year old does not require a primer or surface conditioner to achieve proper membrane adhesion.
(c) Applying Conditioners and Primers.
Thoroughly mix and continuously agitate all primers and conditioners during application according to the manufacturer’s instructions. Uniformly apply primer or conditioner to the entire area to be sealed, at the rate stated in the manufacturer’s instructions, by squeegee, brush or roller. Spray application of the primer is not allowed. Apply a second coat of primer to any areas of concrete which appear dry. Brush out primer that tends to puddle in low spots to permit complete drying. Cure the primer in accordance to the manufacturer’s instructions. Do not let primed areas stand uncovered overnight.
After the primer has dried to a tack free condition, use squeegees or brooms to break any bubbles in the primer. Unless otherwise directed by the Engineer, do not repair the areas where bubbles were broken. If membrane sheets are not placed over primer or conditioner within the time recommended by the manufacturer, recoat the surfaces at no additional cost to the Department.
Before applying the primer or conditioner on a bridge deck, place an oil resistant protective film, held with an adhesive or tape, to any deck areas which will later be covered by expansion dams or headers. Place membrane seal and asphalt concrete across the protective film. When directed by the Engineer, cut the protective film and the preformed sheet at or near the expansion joint.
(d) Adhesive-backed Preformed Membrane Waterproofing Systems.
1. Installation on Bridge Decks.
Before installing any Membrane Waterproofing Systems, drill drain holes, install the drain pipes and galvanized screens as shown on the Standard Drawings.
Apply the preformed membrane sheets, adhesive side down, to the primed or conditioned surfaces either by hand methods or by mechanical applicators. Start placement of the membrane sheets at the low side of the deck and work using a shingle overlap toward the high side of the deck so that a shingled effect is achieved in the direction that the water will drain.
Use either of the two acceptable methods indicated when working from a curb line or barrier railing.
METHOD ONE: As shown on the Standard Drawings and as follows:
Install a 3/4" x 3/4" cant strip made of wood, metal, plastic, mastic, or other approved joint sealing material at a 90 degree angle between the curb face or barrier railing and the deck. Next, install a 12-inch wide curb strip with the top edge of the strip kept a minimum of 1/2-inch below the wearing surface of the asphalt overlay. Put the 12-inch wide curb strip into positive contact with the curb face, cant strip and bridge deck. Seal the curb strip at the top edge with a 2-part urethane liquid membrane or mastic. Overlap the curb strip
which extends onto the deck with the next full width membrane sheet by butting the sheet against the curb face at the gutter line. Lay subsequent membrane sheets longitudinally with 3-inch minimum side laps and 6-inch minimum end laps. Install sheets across the deck until the high side curb line is reached. Install a curb strip along the high side curb line as indicated for the low side curb line.
METHOD TWO: Apply a bead of 2-part urethane liquid membrane or mastic, as recommended by the manufacturer, between the low side curb face or barrier railing and the deck, extending from the gutter line 2 to 3 inches onto the deck. Butt the edge of the membrane firmly against the curb face at the gutter line and embed into the liquid membrane or mastic. Seal the top edge of the membrane at the curb face with a 2-inch bead of liquid membrane or mastic. Lay subsequent membrane sheets longitudinally and side lap with the adjacent sheets not less than 3 inches and end lap by not less than 6 inches. Install sheets across the deck until the high side curb line is reached. Terminate the membrane sheet against the high side curb face. Place a bead of liquid membrane or mastic between the high side curb face and deck. Butt the membrane against the curb face along the gutter line and embed into the bead of liquid membrane or mastic. Seal the top edge of the membrane along the gutter line with a 2-inch bead of liquid membrane or mastic.
After placement, roll the membrane sheets with hand rollers or other apparatus as necessary to develop a firm and uniform bond with the primed or conditioned concrete surfaces. Seal with mastic any laps which were not thoroughly sealed by rolling.
Use procedures which minimize wrinkles and air bubbles. Patch any tears, cuts, or narrow overlaps, using a satisfactory adhesive and by placing sections of membrane sheet over the defective area in such a manner that the patch extends at least 6 inches in every direction beyond the edges of the defect. Vent bubbles of one inch diameter and larger by piercing with a suitable instrument at a nearly horizontal angle and expel the trapped air. Coat vented bubbles with mastic sealer.
Lay the bituminous overlay the same day as the membrane. If overnight delay is unavoidable, keep the construction traffic off the membrane and make a careful inspection for punctures before placing the bituminous overlay. Provide the bituminous overlay at a mix temperature between 300F and 340F. Rubber tired pavers and trucks may be driven on the membrane provided care is taken to prevent sudden starts and stops. Do not allow trucks to turn their front wheels while standing still.
2. Installation of Other Surfaces.
Install as shown on the Standard Drawings, and as specified in Section 680.3(b)1. and as follows:
On vertical surfaces, place preformed membrane material with each successive horizontal sheet lapped top over bottom to the preceding by a minimum of 3 inches. Lap horizontal splices by a minimum of 6 inches. Seal the exposed edges of membrane sheets after the membrane is placed with a troweled bead of a manufacturer's recommended mastic, or 2-part urethane liquid membrane, or with sealing tape.
Provide watertight construction by flashing all projecting pipes, conduits, sleeves, or other facilities passing through the preformed membrane waterproofing with prefabricated or field fabricated boots, fitted coverings or other devices as necessary and approved by the Engineer.
Install protective covers after the application of waterproofing membrane. Apply bonding material, of a type recommended by the waterproofing manufacturer to the surface of the membrane and adjacent concrete surface at a rate, approximately 0.05 gal/sy, sufficient to hold the protective covering in position until the backfill is placed. Allow the bonding material to dry until tacky. Place the sheets of protective board or roofing material on the bonding material with edges or ends of the boards either loosely butt-jointed or overlapped.
(e) Nonstandard Applications.
For areas not covered in this specification regarding special application techniques of the waterproofing materials, or regarding special application restrictions, follow the manufacturer's recommendations.
(f) Defective Work.
Prior to placing backfill, structural backfill, subbase, or bituminous material, repair or replace damaged membranes or protective coverings in accordance with the manufacturer's recommendations at no additional expense to the Department.
SECTION 680.4 MEASUREMENT AND PAYMENT -
(a) Membrane Waterproofing Systems Installed on Bridge Deck.
(b) Membrane Waterproofing Systems Installed on Other Surfaces.
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