SPECIAL PROVISION Concrete Pavement

Transcription

1 1995 Metric CSJ s , etc. SPECIAL PROVISION Concrete Pavement For this project, Item 360, Concrete Pavement, of the Standard Specifications, is hereby amended with respect to the clauses cited below, and no other clauses or requirements of this Item are waived or changed hereby. Article Materials, Subarticle (1) Portland Cement Concrete. The first paragraph is (1) Portland Cement Concrete. Classification and mix design shall conform to Class P Portland cement concrete as defined in Item 421, Portland Cement Concrete, except for the following: The concrete mix shall be designed to meet a minimum flexural strength of 3585 kpa or a minimum compressive strength of 22 MPa at 7 days. Testing shall be in accordance with Test Method Tex-448-A, Flexural Strength of Concrete Using Simple Beam in Third Point Loading or Test Method Tex-418-A, Compressive Strength of Cylindrical Concrete Specimens. A 7- day flexural strength lower than 3585 kpa or a compressive strength lower than 22 MPa is also acceptable, provided the mix meets a minimum flexural strength of 4275 kpa at 28 days. The maximum water cement ratio shall not exceed Article Materials, Subarticle (3) Dowels for Expansion and Contraction Joints is (3) Dowels for Expansion and Contraction Joints. Dowels shall be smooth, straight dowels of the size and type shown on the plans and shall conform to the requirements of ASTM A615, Grade 400. The free end of dowels shall be smooth and free of burrs. When shown on the plans, corrosion protection shall be applied to dowels. Unless otherwise shown on the plans, the entire length of each dowel shall be coated with a hot applied asphalt cement or other de-bonding material approved by the Engineer. At the Contractor's option the dowel may be lightly coated with grease that has been approved by the Engineer. Cut-backs, emulsions or oils shall not be used for the coating. Dowels that have been epoxy coated for resistance to moisture shall also be coated with asphalt or grease as noted. Unless otherwise shown on the plans, 1 end of each coated dowel to be used in an expansion joint shall be encased in an approved cap having an inside diameter of 2 millimeters greater than the diameter of the dowel. The cap shall be of such strength, durability and design as to provide free movement of the dowels and shall be approved by the Engineer prior to use. The end of the cap shall be filled with a soft compressible material or shall be void in order to permit free movement of the dowel for a distance equivalent to 150% of the width of the joint used. The

2 dowel caps and dowels shall be held securely in place by ties as shown on the plans, or as approved by the Engineer. Article Materials is supplemented by the following subarticle: (7) Evaporation Retardant. A list of pretested and approved evaporation retardants will be maintained by the Construction Division, Materials and Pavements Section. The evaporation retardant shall be a commercially available monomolecular film compound certified by the producer to reduce surface moisture evaporation from the concrete when concrete operations are performed in direct sun, wind, high temperatures or low relative humidity. The evaporation retardant shall have no adverse effect on the cement hydration process or the concrete. Evaporation retardants shall be considered for addition to this list when the manufacturer of the evaporation retardant submits a written request certifying that the material to be furnished meet the requirements of this Item. Article Equipment, Subarticle (14) Texturing Equipment is voided and replaced by the following: (14) Texturing Equipment. Texturing equipment shall consist of the following: Carpet Drag. Carpet drag shall be mounted on a work bridge or a moveable support system capable of varying the area of carpet in contact with the pavement. The carpet drag shall be a single piece of carpet of sufficient length to span the full width of the pavement being placed and adjustable so as to have up to a 1.2-meter longitudinal length of carpet in contact with the concrete being placed. Where construction operations necessitate and with the approval of the Engineer, the length and width of the carpet may be varied to accommodate specific applications. The carpeting used shall be an artificial grass type having a molded polyethylene pile face with a blade length of 15 millimeters to 25 millimeters and a minimum mass of 2 kilograms per square meter. The backing shall be a strong, durable material not subject to rot, and shall be adequately bonded to the facing to withstand use as specified. The texturing equipment shall be operated independent from the spreading, finishing and curing equipment and from the curing operation. Hand operated equipment may be approved by the Engineer for use on small or irregular shaped areas, provided an equivalent texture is obtained. Article Quality of Concrete is Quality of Concrete. The quality of concrete shall be in accordance with Item 421, Portland Cement Concrete, and the additional requirements herein. Unless otherwise shown on the plans or permitted by the Engineer, the job control concrete strength shall be by 7-day strength tests in accordance with Test Method Tex-448-A, Flexural Strength of Concrete Using Simple Beam in Third Point Loading or Test Method Tex-418-A, Compressive Strength of Cylindrical Concrete Specimens. When shown on the plans or permitted by the Engineer, the 7-day job control strength tests shall be by Test Method Tex-421- A, Splitting Tensile Strength of Cylindrical Concrete Specimens. When job control is by flexural or compressive strength, the 7-day job control strength shall be 3585 kpa flexural or 22 MPa compressive or a lower value proven to meet a 28-day flexural strength of 4275 kpa as correlated in accordance with Test Method Tex-427-A, Correlating Concrete Strength Tests

3 When job control is by splitting tensile strength, the 7-day job control strength shall be determined by correlating to the specified flexural strength. The correlation shall be determined in accordance with Test Method Tex-427-A, Correlating Concrete Strength Tests. When a job control test value is more than 10% below the required job control strength or when 3 consecutive strength values fall below the required job control strength, an investigation of the strength test procedure, the quality of materials, and batching operation shall be performed by the Contractor and Engineer to determine the likely cause or causes of the problem. Immediate remedial action shall be taken to correct the problem including redesign of the concrete mix when warranted. Article Placement of Reinforcing Steel and Joint Assemblies, Subarticle (3) Placing Reinforcement at Joints. The first sentence of the fourth paragraph is voided and replaced by the following: Tie bars inserted into plastic concrete must develop a pull-out resistance equal to a minimum of 3/4 of the required yield strength of the steel by using a tension test similar to ASTM E488 after the concrete has cured for 7 days. Article Concrete Mixing and Placing, Subarticle (3) Placing. The first paragraph and the Temperature-Time Requirements Table is (3) Placing. At time of placement, the concrete temperature shall not exceed 35 C. The temperature of the concrete will be measured at the time of discharge at the paving operation in accordance with Test Method Tex-422-A. Immediate corrective action shall be taken by the Contractor when the concrete at time of placement exceeds the specified 35 C or the Contractor shall stop production activities. The Contractor will be allowed to transport and place all concrete produced up to the time of being notified of the high concrete temperature. Concrete delivered in agitating trucks shall be discharged within 60 min. after batching. Concrete delivered in non-agitating equipment shall be discharged within 45 min. after batching. In hot weather or under conditions contributing to quick stiffening of the concrete, a time less than permitted above may be required by the Engineer. These time limitations may be extended if the Contractor can demonstrate to the satisfaction of the Engineer that such concrete can be properly placed, consolidated and finished without the use of additional water. Article Concrete Mixing and Placing, Subarticle (3) Placing. The fourth paragraph is Paving equipment and mixers shall not be located on completed pavement, except as herein provided. The paving equipment and mixer may be located and operated on completed pavement when the pavement meets the specified requirements for opening to all traffic in accordance with Subarticle (2) and provided suitable protection to the pavement is provided. Article Concrete Mixing and Placing, Subarticle (5) Cold Weather Precautions. The second paragraph is voided and replaced with the following:

4 It is the Contractor's responsibility to protect the concrete from freezing. When freezing weather is forecasted within a 72-hour period after placement, the Contractor shall submit to the Engineer for approval, proposed measures to protect the concrete. If approved, placement will be allowed, however, the Contractor shall be responsible for the quality and strength of the concrete under cold weather conditions and any concrete damaged by freezing shall be removed and replaced at the Contractor's expense. Article Spreading and Finishing, Subarticle (1) Machine Finishing. The seventh, eighth, and ninth paragraphs are Final finish shall consist of a carpet drag finish and shall be completed before the concrete has attained its initial set. The final finish shall be accomplished by drawing the specified carpet drag longitudinally along the pavement. The carpet shall be kept from getting plugged with grout. There shall not be excessive bleed water during the carpet drag. The texture achieved by the carpet drag shall be tested by the Contractor in accordance with ASTM E965-87, Test Method for Measuring Surface Macrotexture Depth Using a Sand Volumetric Technique. The Engineer will determine test locations, on average one test per 300 meters per lane. The texture depth shall have a minimum value of 1 millimeter. Limits of any failing individual test shall be determined by additional tests at 30-meter intervals before and after the failing test location. For the failing section, diamond grinding will be required to attain the necessary texture of 1 millimeter. All testing of the surface texture shall be completed no later than one day after pavement placement. Article Curing, Subarticle (3) Membrane Curing. The first paragraph is voided and replaced by the following: (3) Membrane Curing. After final finish and immediately after the free surface moisture has disappeared, the concrete surface shall be sprayed uniformly with a curing compound in accordance with Article After the initial curing compound has dried, the concrete surface shall be sprayed uniformly with a second application of curing compound in accordance with Article Should the membrane be damaged from any cause before the expiration of 72 hours after original application, the damaged portions shall be repaired immediately with additional compound. Article Protection of Pavement and Opening to Traffic, Subarticle (2) Opening Pavement to Traffic is voided and replaced with the following: (2) Opening Pavement to Traffic. The opening of the pavement to either vehicles of the Contractor or to all traffic shall in no manner relieve the Contractor from his responsibility for the work in accordance with Item 7, Legal Relations and Responsibilities to the Public. For those sections of pavement to be opened to traffic, all joints shall first be sealed, the pavement cleaned, stable material placed against the pavement edges, unless otherwise shown on the plans, and all other work performed as required for the safety of traffic

5 The pavement shall be closed to all traffic, including vehicles of the Contractor, until the concrete is as least 4 days old. After 4 days, the pavement may be opened for use by vehicles of the Contractor provided the gross weight (vehicle plus load) of such vehicles and/or equipment does not exceed 6350 kilograms. Where a detour is not readily available or economically feasible to use, an occasional crossing of the roadway with overweight equipment may be permitted for relocating equipment only, but not for hauling material. When an occasional crossing of overweight equipment is permitted, temporary matting or other methods may be required by the Engineer. After the concrete in any section of pavement is 7 days old, such section of pavement may be opened to all traffic as shown on the plans or directed by the Engineer. The pavement may also be opened to all traffic after the pavement has cured for a period of 4 curing days, and laboratory cured concrete specimens have attained either a flexural strength of 3100 kpa, a compressive strength of 19 MPa, or a splitting tensile strength of 2275 kpa. A curing day is defined as a calendar day when the temperature, taken in the shade, away from artificial heat, is above 10 C for at least 19 hours or if satisfactory provisions are made to maintain the surface temperature of the concrete above 4 C for the entire 24 hours. The required curing period shall begin when all concrete therein has attained initial set. Article Deficient Pavement Thickness, Subarticle (a) Coring. The first paragraph is (a) Depth Checks. The pavement will be tested for depth by direct measurement as approved by the Engineer after final strike off or by coring prior to final acceptance if significant surface deviation corrections were required. The direct measurement method shall be in accordance with Test Method Tex-423-A. Locations of depth tests will be selected by the Engineer. If the thickness of the pavement indicated by the direct measurement depth test is deficient by more than 5 millimeters from the plan thickness, the thickness will be verified by measurement of cores taken by the Contractor in accordance with Test Method Tex-424- A at the locations selected by the Engineer. Article Deficient Pavement Thickness, Subarticle (a) Coring. The fourth paragraph is A minimum of 2 direct measurement depth tests will be taken by the Department at locations selected by the Engineer or at random in each 300-meter unit. When no single direct measurement from any unit is deficient by more than 5 millimeters from the plan thickness, full payment will be made. When any direct measurement depth test is deficient by more than 5 millimeters, but not by more than 20 millimeters from the plan thickness, 3 cores will be taken from the unit and the average of the 3 cores determined. The cores from any 300-meter unit will be taken at intervals of not less than 45 meters. The cores from any 300-meter unit will be taken at locations such that the pavement in the unit will be well represented. If the average measurement of these 3 cores is not deficient more than 5 millimeters from the plan thickness, full payment will be made. If the average thickness of the 3 cores is deficient by more than five (5) millimeters but not more than 20 millimeters from the plan thickness, an adjusted unit price as provided in (b), Price Adjustments, will be paid for the unit represented by these cores

6 Article Deficient Pavement Thickness, Subarticle (a) Coring. The sixth paragraph is When the measurement of any individual core is less than the specified thickness by more than 20 millimeters, the actual thickness of the pavement in this area will be determined by taking cores at 3-meter intervals parallel to the centerline in each direction from the deficient depth test until, in each direction, a core is taken which is not deficient by more than 20 millimeters. Exploratory cores for deficient thickness will not be used in averages for adjusted unit price. Exploratory cores are to be used only to determine the length of pavement in a unit that is to be left in place without pay and/or removed and replaced as provided in (a), Coring. Article Ride Quality is Ride Quality. Unless otherwise shown on the plans, ride quality will be required in accordance with Special Specification, Ride Quality for Pavement Surfaces. Article Measurement, Subarticle (3) Ride Quality is voided and replaced by the following: (3) Ride Quality. Ride Quality will be measured as described in Special Specification, Ride Quality for Pavement Surfaces. Article Payment. The second sentence of the first paragraph is voided and replaced by the following: This price shall be full compensation for furnishing, loading, unloading, storing, hauling and handling of all concrete ingredients, including all freight and royalty involved; for coring; for placing and adjusting forms, including supporting material or preparing track grade; for furnishing and installing all reinforcing steel; for furnishing all materials for sealing joints and placing longitudinal, expansion and weakened-plane joints, including all steel dowel caps and load transmission devices required; for mixing, placing, finishing, curing and sawing concrete; for cleaning and sealing concrete joints; and for all manipulations, labor, tools, equipment and incidentals necessary to complete work. Article Payment. The second paragraph is When Surface Test Type-B, as specified in Special Specification, Ride Quality for Pavement Surfaces, is used, a bonus or deduction for each kilometer section of each travel lane will be calculated in dollar and cents