602.03 Concrete Composition. Concrete composition shall at the Engineer's option, be determined by using either Method A or Method B as specified below: Method A-The concrete shall contain 5 ± 1 percent of entrained air, as determined by AASHTO T 152. Concrete shall have a slump of not more than 4 inches as determined by AASHTO T 119. The concrete shall develop a minimum compressive strength of 3000 psi in 28 days as determined by test cylinders made in accordance with AASHTO T 23 and tested in accordance with AASHTO T 22. Failure of two of three cylinders for any pour shall require the removal of the concrete and its replacement at the contractor's expense. The Engineer may take test cylinders for accelerated strength determinations in accordance with ASTM C 684. If the strength level of the concrete as determined by the accelerated 1 or 2-day tests indicates that the 28-day strength potential will meet or exceed the requirements, the Engineer may waive the 28-day requirements and accept the concrete on the basis of the accelerated strength. Method B-Certification. The Engineer may approve the use of portland cement concrete on the basis of a certification. The Contractor shall submit for approval the following statement: (a) The type and sources of aggregates. (b) Type and source of cement. (c) Scale weights of each aggregate proposed as pounds per cubic yard of concrete. (d) Quantity of water proposed as pounds per cubic yard of concrete. (e) Quantity of cement proposed as pounds per cubic yard of concrete. The concrete shall contain not less than 517 pounds of cement per cubic yard. The concrete shall be subject to acceptance or rejection by visual inspection at the job site. Retempering concrete will not be permitted. When a commercial supplier is used the contractor shall furnish a certification with each truck load of concrete certifying that the material and mix proportions used are in conformance with the approved mixture. Concrete meeting the material and proportioning requirements of Class A(AE) concrete will be acceptable as an approved mixture and may be certified to as such. Construction Requirements 602.04 Forms. Forms shall be so designed and constructed that they may be removed without injuring the concrete. They shall be free of bulge and warp, and constructed in such manner that the finished concrete shall be of the form and dimensions shown on the plans, and true to line and grade. 602.05 Placing Concrete. Concrete shall be placed in such manner as to avoid segregation. High-frequency internal vibrators shall be used for compacting concrete in the forms. Vibrators shall be so manipulated as to produce concrete free of voids, but shall not be held so long in one place as to result in segregation or formation of laitance on the surface. When concrete is placed by the pumping method or by tremie operations, the use of aluminum pipe or conduit for transporting the concrete will not be permitted. When concrete is pumped, sampling shall be from the discharge stream at the point of placement. When placing concrete at or below an atmospheric temperature of 35° F., the Contractor shall comply with the applicable requirements under Subsection 552.08. Concreting operations shall not be permitted under any circumstances when the atmospheric temperature is less than 20° F. or whenever the temperature may fall below 20°F. 602.06 Curing Concrete. All concrete will be cured a minimum of 7 days, or, if high early strength cement is used, a minimum of 3 days. The concrete shall be cured in accordance with subsection 552.13. Method of Measurement 602.07 Concrete. The quantity of concrete to be paid for on this contract shall be the final quantity in accordance with subsection 109.05. 602.08 Other Items. Reinforcing steel, anchor bolts or other approved fastenings and any other incidental items included in the completed and accepted structure shall not be measured for payment, but shall be considered incidental to other work performed under this section. Basis of Payment 602.09 The quantities, determined as provided above, will be paid for at the contract price per unit per measurement for the pay item listed below, which price and payment shall be full compensation for furnishing and placing all materials, including all labor, equipment, tools, and incidentals necessary to complete the work prescribed in this section. Excavation and backfill will be measured and paid for as provided in Section 206. 603.01 This work shall consist of the construction or reconstruction of pipe culverts and storm drains (conduit), in accordance with these specifications and in reasonably close conformity with the lines and grades shown on the plans or established by the Engineer. Materials 603.02 Materials. Materials shall meet the requirements specified in the following subsections: 706.14 Reinforced Concrete Arch Culvert, Storm Drain and Sewer Pipe.... 706.18 Acrylonitrile-Butadiene-Styrene (ABS) sewer pipe. 706.19 Acrylonitrile-Butadiene-Styrene (ABS) Composite Sewer Pipe 706.20 706.21 Corrugated Iron or Steel Pipe and Pipe Arches.. 707.02 Bituminous Coated Corrugated Iron or Steel Pipe and Pipe Arches. 707.03 Full Bituminous Coated Structural Plate Pipe, Pipe Arch and Arches... 707.11 Aluminum Alloy Structural Plate for Pipe, Pipe Arch and Arches... 707.12 Bedding material shall conform to the requirements of subsection 603.04. Backfill materials shall conform to the requirements of subsection 603.08. When the location of manufacturing plants allows, the plants will be inspected periodically for compliance with specified manufacturing methods, and material samples will be obtained for laboratory testing for compliance with materials quality requirements. This can be the basis for acceptance of manufacturing lots as to quality. Prior to and during incorporation of materials in the work, these materials will be subject to the latest practicable inspections and checks by the Engineer. It is not necessary that all culvert pipe be of the same kind of material; however, all contiguous pipe shall be of the same kind. Special sections, such as elbows, branch connections, tapered inlets, and end sections, shall be of the same material as the culvert pipe to which they are attached. Bituminous coated end sections shall be coated in conformity with AASHTO M 243 or AASHTO M 190. Construction Requirements 603.03 Excavation. Trenches shall be excavated in accordance with the requirements of Section 206-Structure Excavation, to a width sufficient to allow for proper jointing of the conduit and thorough compaction of the bedding and backfill material under and around the conduit. The completed trench bottom shall be firm for its full length and width. Where required, in the case of cross drains, the trench shall have a longitudinal camber of the magnitude specified. When so specified on the plans, the excavation for conduits placed in embankment fill, shall be made after the embankment has been completed to the specified or directed height above the designed grade of the conduit. 603.04 Bedding. The conduit bedding shall conform to one of the classes specified. When no bedding class is specified or detailed on the plans the requirements for Class C bedding shall apply. Class A bedding shall consist of a continuous concrete cradle conforming to the plan details. Class B bedding shall consist of a bed of granular material having a thickness of at least 6 inches below the bottom of the pipe and extending up around the pipe for a depth of not less than 30 percent of its vertical outside diameter. The layer of bedding material shall be shaped to fit the conduit for at least 10 percent of the vertical diameter of the conduit and shall have recesses shaped to receive the bell of bell-and-spigot pipe. The bedding material shall be sand or selected sandy soil all of which passes a 3⁄4-inch sieve and not more than 10 percent of which passes a No. 200 sieve. Class C bedding shall consist of bedding the conduit to a depth of not less than 10 percent of its total height. The foundation surface, completed in accordance with subsection 206.03(c) shall be compacted and shaped to fit the conduit and shall have recesses shaped to receive the bells, if any. For flexible pipe the bed shall be roughly shaped and a bedding blanket of sand or fine granular material shall be provided as follows: For large diameter structural plate pipes the shaped bed need not exceed the width of bottom plate. Alternate methods of constructing Class B or C beddings similar to those detailed in ASCE Manual Number 9 may be approved by the Engineer upon submittal of a written request by the contractor. 603.05 Laying Conduit. The conduit laying shall begin at the downstream end of the conduit line. The lower segment of the conduit shall be in contact with the bedding for the required depth throughout its full length. Bell or groove ends of rigid conduits and outside circumferential laps of flexible conduits shall be placed facing upstream. No conduit shall be placed in service until a suitable outlet is provided. Paved or partially lined conduit shall be laid so that the longitudinal center line of the paved segment coincides with the flow line. Elliptical and elliptically reinforced conduits shall be placed with the major axis within 5 degrees of a vertical plane through the longitudinal axis of the conduit. 603.06 Joining Conduit. Rigid conduits may be of bell and spigot or tongue and groove design unless one type is specified. Conduit sections shall be jointed such that the inner surfaces are reasonably flush and even, and the ends are entered as required. Joints shall be made with (a) portland cement mortar, (b) portland cement grout, (c) rubber gaskets, (d) oakum and mortar, (e) oakum and joint compound, (f) plastic sealing compound, or by a combination of these types, or any other approved type, as may be specified. Mortar joints shall be made with an excess of mortar to form a continuous bead around the outside of the conduit and finished smooth on the inside. For grouted joints, molds or runners shall be used to retain the poured grout. Rubber ring gaskets shall be installed so as to form a flexible watertight seal. Where oakum is used the joint shall be calked with this material and then sealed with the specified material. Joints in concrete pipe shall be thoroughly wetted before mortar or grout is applied. When portland cement mixtures are used, the completed joints shall be protected against rapid drying by a suitable curing method. Flexible conduits shall be firmly joined by coupling bands. When bands with projections (dimples) are used the pipe joints shall be sealed with a continuous sponge rubber strip, 2 inches wide and one inch thick conforming to ASTM D1056, Grade RE41. Conduit shall be inspected before any backfill is placed. Any pipe found to be substantially out of alignment, unduly settled, or damaged shall be taken up and relaid or replaced. 603.07 Shop Elongation. Where required by the plans, the vertical diameter of round flexible conduit shall be increased 5 per cent by shop elongation. 603.08 Backfilling. Materials for backfill on each side of the conduit for the full trench width and to an elevation of 1 foot above the top of the conduit, shall be fine, readily compactible soil or granular material selected from excavation or from a source of the contractor's choice. It shall not contain frozen lumps or stones larger than 2 inches in diameter, chunks of highly plastic clay, or other objectionable material. Oversized material, if present, shall be removed at the source of the material, except as directed by the Engineer. When the top of the conduit is even with or below the top of the trench, backfill material shall be placed at or near optimum moisture content and compacted in layers not exceeding 6 inches (compacted) on both sides and to an elevation 1 foot above the top of the conduit. Care shall be exercised to thoroughly compact the backfill under the haunches of the conduit. The backfill shall be brought up evenly on both sides of the conduit for the full required length. Except where negative projecting embankment-type installation is specified, the backfill material shall be placed and compacted for the full depth of the trench. When the top of the conduit is above the top of the trench, backfill shall be placed at or near optimum moisture content and compacted in layers not exceeding 6 inches (compacted) and shall be brought up evenly on both sides of the conduit for its full length to an elevation 1 foot above the top of the conduit. The width of backfill on each side of the conduit for the portion above the top of the trench shall be equal to twice the diameter of the conduit or 12 feet, whichever is less. The backfill material used in the trench section and the portion above the top of the trench for a distance on each side of the conduit equal to the horizontal inside diameter and to 1 foot above the top of the conduit shall conform to the requirements for backfill material in the first paragraph of this subsection. The remainder of the backfill shall consist of material from excavation and borrow that is suitable for embankment construction. Compaction to the density specified in subsection 203.19 shall be achieved by use of mechanical tampers or by rolling. 603.09 Induced Trench. Under this method, for rigid conduit, the embankment shall be completed as described above, to a height above the conduit equal to the vertical outside diameter of the conduit plus one foot. A trench equal in width to the outside horizontal diameter of the conduit and to the length shown on the plans or as directed, shall then be excavated to within one foot of the top of the conduit, trench walls being as nearly vertical as possible. This trench shall be loosely filled with highly compressible soil. Straw, hay, corn stalks, leaves, brush, or sawdust may be used to fill the lower 1⁄4 to 1⁄2 of the trench. Construction of embankment above shall then proceed in a normal manner. In no case shall the induced trench extend for the full length of the conduit. 603.10 Slotted Pipe. The pipe shall be placed in accordance with the provisions in Section 603. The slot shall be covered with roofing paper or other approved covering during backfilling and paving operations to prevent infiltration of material into the pipe. Watertight joints shall be provided, when required by the plans, by placing a joint sealant between the coupling band and the periphery of the pipe section ends. The joint sealant material shall: (a) Be an extruded strip or bead compounded from a non-drying, non-toxic, synthetic resin base with butyl rubber and inorganic extenders and be 100 percent solid material with no shrinkage. (b) Be furnished in 5%" x 1" strips or one inch diameter beads on one inch wide release paper and wound into rolls. (c) Have sufficient adhesion so the strip or bead will adhere to galvanized steel and be soft enough to allow cold flow when compressed during connection of the pipe sections. (d) Not flow or sag at temperatures up to 180°F., nor become brittle, crack or lose adhesion at temperatures down to -30°F. (e) Contain no migrating components that could leach out nor produce any chemical reaction with galvanized steel. An alternative joint sealant or sealing method that will provide a watertight joint may be used provided said alternative sealant or method is approved, in writing, by the Engineer. 603.11 Contact Surfaces. When aluminum alloys come in contact with concrete, the contacting surfaces shall be coated with asphalt mastic, AASHTO M 243, or an aluminumimpregnated calking compound. Method of Measurement 603.12 Conduit of the different types and sizes, both new and relaid, will be measured by the linear foot in place. Conduit with sloped or skewed ends will be measured along the invert. |