Section 710. WATERPROOFING AND PROTECTIVE COVERS Description. Furnish and place membrane waterproofing and protective covers.

Transcription

1 Section 710. WATERPROOFING AND PROTECTIVE COVERS Description. Furnish and place membrane waterproofing and protective covers Materials. Use materials meeting the following. Waterproofing Primer: RC Water Joint and Waterproofing Materials Select preformed waterproofing membrane and expansion joint waterproofing from the Qualified Products List. Use preformed waterproofing membrane or expansion joint waterproofing systems that include a manufacturer s specified surface primer. Use waterproofing agent: asphalt cement WOA meeting the requirements of ASTM D 449, Type II. When the waterproofing agent for membrane waterproofing is asphalt cement WOA, use RC-250 primer. Supply shotcrete material recommended by the manufacturer for use as a pneumatically applied concrete and secure approval of the Engineer before its use on the project Construction. A. Joint Waterproofing. Where joints in concrete are to be waterproofed, use either hot applied or preformed waterproofing. 1. Hot Applied. Prepare and prime the surface for a distance of 12 inches each side of the joint. Complete preparatory work when the air and concrete temperatures are above 40 F and the surfaces are dry. Clean the entire surface to be covered of all foreign materials such as oil, grease, old waterproofing material, and asphalt residue, by scraping, and the use of a suitable solvent. Fill all rod holes and other voids greater than 3 4 inch in diameter with an approved epoxy mortar, Portland cement mortar, or concrete and allow to cure as directed. Remove all sharp protrusions by grinding. Cure new concrete at least seven days before applying prime coat, including repair areas. Remove dust from the concrete surface by brushblasting with compressed, oil free air. 459

2 Apply the prime coat at not less than one gallon per 100 square feet of surface. Allow the prime coat to thoroughly set before continuing. Apply a second coat of hot asphalt and press a 10 inch wide strip of waterproofing fabric into it, centered over the joint. Apply a third coat of hot asphalt, 24 inches wide, and a strip of fabric 18 inches wide centered over the joint. Apply a fourth coat of hot asphalt covering the fabric and lapping onto the concrete. Apply the second, third and fourth coats of hot asphalt (temperature recommended by supplier) at not less than 4.5 gallons per 100 square feet of surface. 2. Preformed. Provide preformed joint waterproofing a minimum 18 inches wide. Apply the preformed waterproofing membrane system to the concrete surface a minimum of four hours after removal of the forms. Prepare and prime the surface for a distance of 12 inches each side of the joint. Complete preparatory work when the air and concrete temperatures are above 40 F and the surfaces are dry. Clean the entire surface to be covered of all foreign materials, such as oil, grease, old waterproofing material, and asphalt residue by scraping, and the use of a suitable solvent. Remove all protrusions that could puncture the membrane or cause a void beneath the membrane greater than 3 4 inch in diameter, before application of the primer. Remove dust from the concrete surface with compressed, oil free air. Fill surface imperfections, potholes and spalls with an approved epoxy mortar, Portland cement mortar, or concrete and cure. Cure Portland cement based patching mixtures a minimum of 24-hours before installation of the membrane. Apply the primer with a roller or brush, according to the manufacturer s recommendations, over the entire concrete surface to receive the membrane. Apply an additional application of primer if the membrane is not placed within the time specified by the membrane system manufacturer. Apply the membrane according to the manufacturer s recommendations. Remove the release paper from the back surface of the membrane immediately before placing the membrane. Center the membrane over the concrete joint, straight and wrinkle-free. Immediately after each sheet of membrane is applied, hand roll with a suitable roller, with sufficient pressure to remove all air voids and ensure complete adhesion. Overlap seams a minimum of 6 inches. 460

3 Before backfilling, demonstrate to the Engineer that the entire surface of membrane has fully adhered to the underlying concrete surface. Repair all punctures, tears, wrinkles, or other imperfections in the installed membrane. Make repairs either by removing and replacing the membrane, or by applying a patch of membrane over the damaged material. Size patches to extend six inches beyond the perimeter if the repair area. Waterproofing membrane system which exhibits loss of adhesion to the concrete surface may be rejected. B. Expansion Joint Waterproofing. Apply a two-layer preformed joint waterproofing membrane system at integral and semi-integral abutment backwall locations. Subsection A.2 applies with only the following modifications. Provide preformed waterproofing membrane a minimum of 18 inches wide. Apply a bond breaker tape, or equivalent material, to the face of each of the two beveled surfaces, next to the expansion joint at the abutment wall/backwall interface, to prevent adhesion of the membrane fold to these concrete surfaces. Do not apply primer to the two beveled surfaces next to the expansion joint at abutment/backwall interface that will receive the bond breaker tape. Center the membrane over the concrete joint, straight and wrinkle-free, and insert full-depth into the beveled cavity of the expansion joint to provide slack in the membrane for bridge movement. Apply a second layer of membrane over the first layer similarly. Do not use bond breaker tape for this second layer. Before applying the second layer of membrane, coat the entire exposed surface of the first layer of membrane, including the fold, with primer. Center the second layer of membrane over the concrete joint, straight and wrinkle-free. Conform and fully adhere to the underlying first layer of membrane. C. Preformed Waterproofing Membrane. 1. Construction Procedure. Prime and place the membrane when the air and concrete temperatures are above 40 F and the surfaces are dry. 461

4 Allow concrete, including grout and repair areas, to cure for at least seven days before applying the primer. Clean the surface of all foreign materials such as oil or grease by scraping and the use of a suitable solvent. Remove sharp protrusions by grinding. Remove old membrane material or asphalt residue by methods approved by the Engineer. Fill potholes and spalls greater than 3 4 inch in diameter with an approved epoxy mortar, Portland cement mortar, or concrete and cure as directed. Wedge elevation differences in the tops of box beams, such as those resulting from camber variation, with Portland cement mortar or concrete. Sweep and clean all surfaces with brooms and compressed air as directed. Apply the primer after the deck has been cleaned. Apply by roller, brush, squeegee, or mechanical means and only to the deck surface and 2 to 3 inches up the vertical face of the curb. Prime only those surfaces that will be covered by membrane that day. Allow the primer to dry so that it is not tacky when walked on. Drying time may vary from 1 2 hour to hours depending on the air temperature. Small bubbles on the primer are normal and do not affect the subsequent bond. After the primer has cured or dried, apply an approved liquid fillet material to all inside corners. Apply an approved mastic to all locations where membrane edges will fall, including the curb face, raised expansion dams, or drain castings. Apply an 8 inch strip of the sheet membrane to the vertical surface of the curb to a height at least equal to the depth of hot mix asphalt (HMA) to be placed. Place an 8 inch wide strip of membrane centered over transverse joints or cracks greater than 3 16 inch in width, except do not place the strip at raised steel expansion dams. Firmly press the membrane into the primer and mastic. Starting at the low or down slope side of the deck, place the membrane by either hand or with equipment designed for this purpose. Shingle-lap successive strips of membrane. Place the membrane straight, wrinkle free with no bubbles or air spaces under the membrane. Overlap all edges and ends of the membrane a minimum of 6 inches. At the drain spouts, cut the membrane and turn down into the spouts or bleeder pipes. Apply a continuous bead of approved mastic along the base of raised expansion dams, butt the sheet membrane up to the dam and press into the mastic. 462

5 Immediately after installation of each sheet of membrane, hand roll with a suitable roller of sufficient weight to ensure total contact with the deck. Patch all torn or cut areas, or narrow overlaps, by placing sections of the membrane over the areas so that the patch extends a minimum of 6 inches beyond the defect in all directions. Roll the patch or press firmly in place and apply an approved mastic to the edges. Remove the separation sheet of plastic or paper as specified by the manufacturer during the installation of the membrane and before the application of the HMA. Discard the separation sheet properly. Remove stones or other foreign matter found under the membrane after application and patch the area as previously described. Do not allow vehicles, except HMA hauling units and the approved rubber-tired paver on the completed waterproofing membrane. 2. Placing HMA. Place the mixture between 250 and 350 F using standard procedures as soon as possible after placing the membrane. Pave only on a dry membrane surface. Use rubber-tired equipment. Inspect equipment and remove burrs on tires, stones, or sharp projections that could damage the membrane. If the rubber-tired machine skids during warm weather, broadcast a very small quantity of fine sand or cement in the tire paths. Excess use of cement or sand could prevent adhesion of the HMA. Deliver the HMA directly from the hauling unit to the paver. Do not stop the paver with a full hopper. Prevent build up of material in the auger. Use extreme care in restarting after a stop. Preheat paver screeds, but turn burners off during paving to avoid damaging the membrane. Keep the level of the HMA in the auger just below the level of the auger shaft. Avoid sudden stops or sharp turns with the compaction rollers. After rolling the surface, apply a fillet or cove seal using the asphaltmineral, fiber-solvent caulking material supplied with the membrane. Apply the seal at the curb line to form a 3 4 inch by 3 4 inch triangular seal along the edge of the new surface, the full length of the curb. 463

6 D. Shotcrete. Shotcrete will consist of a premixed, latex modified, Portland cement and fine aggregate. Pneumatically eject the mixture from a mixer/gun through a hose and discharge nozzle, all under regulated pressure. Add the liquid latex component at the mixer/gun or at the nozzle, depending on equipment type and material manufacturer s recommendations. 1. Nozzle Operators. Demonstrate to the Engineer, the ability of all nozzle operators to correctly gun latex modified shotcrete. Test panels simulating job conditions for each gun shooting position (down, horizontal, overhead) encountered. Use the same shotcrete material proposed for use on the project. Use a panel 2 feet by 2 feet square and the same thickness as required on the project, but not less than 3 inches. Provide at least one-half the panel area with the same reinforcing steel pattern encountered on the project. Keep test panel(s) continuously moist and above 40 F for five days. Remove at least five cores from the test panels and test for compressive strength according to ASTM C 39. Cut cores a minimum of 3 inches in diameter and with a length to diameter ratio (L/D) of at least 1.0. Adjust core strengths according to ASTM C 42 if L/D is less than 2.0. The average compressive strength of the cores must be at least 85 percent of the required compressive strength with no individual core below 75 percent of the required compressive strength. Take additional cores through the reinforcing steel so that the Engineer can evaluate the soundness of the shotcrete behind the steel. The Engineer will examine all cored surfaces and require additional cores or saw cuts when necessary to evaluate soundness and uniformity of deposited material. Surfaces must be dense and free from laminations, voids and sand pockets. 2. Surface Preparation. When shotcrete is applied to protect waterproofing, perform the work immediately after the waterproofing is complete. When shotcrete is for repair of concrete members, remove all unsound concrete from the existing substrate. Remove concrete contaminated by chemicals or oils. Saw cut and repair the edges of the repair and patch to a minimum depth of 1 2 inch. If impact tools are used to remove concrete, choose tools to avoid damage to sound concrete surrounding and beneath the area being removed. 464

7 Use galvanized or epoxy-coated welded wire reinforcing on all repairs greater than 2 inches in depth. Place the reinforcing at middepth of the repair, but no less than 1 inch below the surface. Attach the reinforcing to sound concrete with stainless steel anchoring devices spaced no farther apart than an 18 inches by 18 inches grid. Use anchors that can support three times the weight of shotcrete contributing to each anchor. Blast clean the area and remove all traces of dirt, oil, and loose material. Follow with an oil-free air blast to remove abrasive and dust. 3. Placement. Prewet the surface with the liquid latex component immediately before placement. Balance air and material to assure a steady flow and to prevent slugging of material, plugging, and excess rebound. Add liquid so that the deposited material is neither too dry, creating sandy pockets, nor too wet, causing sagging or sloughing off. Place each layer of shotcrete in several passes over a section of the work area. Divide large expanses into smaller areas and apply shotcrete to its full thickness before moving to the next area. Avoid laminations during placement. Keep the nozzle 2 to 6 feet from the work. Hold the nozzle as near to perpendicular to the surface as possible, and never at more than 45 degrees to the surface. Remove rebound and overspray that does not fall clear. Do not salvage and recycle rebound and overspray. Do not apply shotcrete under the following conditions. a. High wind preventing proper application. b. Surface temperature below 45 F. c. Rain causing washouts or sloughing of the fresh shotcrete. 4. Curing. Cure and provide temperature protection according to subsection N

8 5. Testing. The Engineer may require cutting cores from the completed work for compression testing. When the Engineer orders tests, obtain and test a minimum of three cores according to subsection D Measurement and Payment. Contract Item (Pay Item) Pay Unit Joint Waterproofing...Square Foot Joint Waterproofing, Railroad...Square Foot Shotcrete...Square Foot, Cubic Foot Membrane, Preformed Waterproofing...Square Foot Joint Waterproofing, Expansion...Square Foot A. Joint Waterproofing will be measured by area based on a width of 18 inches and plan quantities of joint length to be treated. B. Membrane, Preformed Waterproofing will be measured by area covered, with no allowance for laps, patches, the 8 inch strips over transverse joints or cracks, or the 8 inch strip applied to the vertical surface of the curb. The areas of expansion dams or drain spouts will not be deducted. The work includes cleaning the deck, applying the primer, liquid fillet material, and mastic, where required, applying, rolling, and repairing the membrane, and applying the final cove seal mastic along the curb line. C. Joint Waterproofing, Expansion, includes preparing the concrete surfaces and installing the two-layer preformed expansion joint waterproofing membrane system. Joint Waterproofing, Expansion will be measured by area based on a width of 18 inches and plan quantities of joint length to be treated. No additional compensation will be made for area of folds, or overlapped material. D. Shotcrete includes surface preparation; furnishing, mixing and applying shotcrete material; and all test panels and coring as required. E. Removing HMA surface, when necessary, will be measured and paid for separately according to subsection Removing old membrane will be considered to be included in the pay item HMA Surface, Rem. Scarifying, hand chipping, and patching, when necessary, will be measured and paid for separately according to subsection , except 466

9 that when it is not feasible to determine the amount of scarifying, hand chipping, and patching required prior to removal of the HMA surface, payment will be by force account. F. Any necessary wedging along joints between prestressed concrete box beams that have been inspected and accepted by the Department will be measured and paid for separately as Patching Mortar or Concrete according to subsection The HMA mixture will be measured and paid for separately according to subsection