§ 4.0. Concrete pavement.

4.1.
This item consists of the placement of a 4,000 psi test Portland concrete pavement, a minimum of eight inches thick, on major and collector streets and a minimum of six inches thick on minor streets.

4.2.
No concrete shall be placed until the base has been approved by the city engineer or his designated inspector.

4.3.
Materials:

4.3.01. Portland cement shall conform to ASTM C-150 Type 1, latest revision.

4.3.02. Sand shall consist of clean, sound, durable grains, free from dust, dirt, clay or harmful substances.

4.3.03. Coarse aggregate shall be of hard durable rock or gravel, free from shale or decomposed pieces. (ASTM C-33).

4.3.04. Water used in mixing concrete shall be clean and free from deleterious amounts of acid, alkali or organic material.

4.3.05. Water used in concrete shall be potable water fit for human consumption unless water of a lesser quality is approved in writing by the engineer.

4.3.06. Expansion joint filler shall be premolded, nonextruding type.

4.3.07. Tie bars: Steel bars shall conform to the requirements of ASTM specification A-615, A-616 and A-617, latest revision.

4.3.08. All tie bars shall be securely held in place by the use of spacers, wire chairs or other approved methods, which will satisfactorily maintain such steel in the position shown on the plans.

4.3.09. Longitudinal center joints. As indicated on the plans, the pavement shall be constructed with a longitudinal joint in the center of the pavement. This joint shall be formed by means of a metal strip of the gauge and form shown on the plans and may be either plain, painted or galvanized as shown on the plans. The metal strips shall be not less than ten feet and not more than 15 feet in length made of one single strip of metal, and shall be held rigidly in place by suitable pins at least 12 inches long, driven vertically through punched holes in the joint. Except at all transverse joints where a gap of one inch must be provided, adjoining strips shall be lapped not less than two inches and securely fastened by means of the pins driven through matched holes in the splice or butt joints may be constructed if suitable clips approved by the city are used. The spacing of the holes and the pins shall be in no case greater than shown on the plans. Punched or cut holes shall be provided in the metal strip, spaced as shown on the plans, to receive the transverse tie bars across the center joint. These bars shall be of length, size and installed as shown on the plans.

4.3.10. Expansion and contraction joints. Expansion and contraction joints shall be constructed using redwood board expansion fillers conforming to AASHO designation M90-42 Standard Specifications. "Starlug" load transfer and expansion and contraction devices as manufactured by Texas Foundries, Lufkin, Texas, shall be used, or an equal device approved by the engineering department. The starlug and filler shall be a complete unit assembled and ready for setting in place.

4.3.11. Joint sealing material. Material for pouring seal on expansion joints and for filling dummy joints shall be an asphalt filler conforming to the latest revision of AASHO Specifications M-18 Type A or an approved mastic filler.

4.3.12. Curing agents. Curing agents shall be wet burlap, pending or white pigmented impervious membrane. The material shall be at least equal to "Hunt's" white pigment.

4.3.13. Forms. Forms shall be of steel and shall have a depth equal to slab thickness. Form sections shall have a length of at least ten feet on tangents. On curves, shorter sections or wood forms may be used.

4.3.14. Admixtures. Air-entraining and cement-dispersing agents such as possolith, as manufactured by Master Builders Company or equal will be permitted in concrete at the option of the contractor provided the admixture meets with the approval of the city. Only one brand will be permitted throughout the entire job. The product must be dispersed in liquid form, accurately measured and introduced into the mixture at the same time as the sand, gravel, cement and water are combined in the mix.

4.3.15. Reinforcing steel. In the event reinforcing steel is required for concrete pavement, such reinforcement shall be designed by a professional engineer and approved by the city engineer. Reinforcing steel shall be new billet steel and meet the requirements of the ASTM designation: A-615-68, Grade 40 deformed bar, and subsequent revisions, for concrete reinforcement. The steel shall be stored in such a manner so as to be protected from mechanical injury and surface deterioration caused by exposure to conditions producing rust. When placed in the work, it shall be

free from dirt, scale, rust, paint, oil or other injurious materials and be tied at each bar intersection.

4.3.16 Fiber reinforcing. All concrete pavements shall contain macro synthetic fiber reinforcement for temperature and shrinkage crack width control. This fiber will be used instead of highway mesh. This fiber shall be as follows:

(1)

For all roadway pavements, Fibermesh 650, or approved equal, shall be applied throughout the concrete mixture. Macro synthetic fibers shall provide a minimum average residual strength per ASTM C 1399 of 162 psi at three pounds per cubic yard, and 216 psi at four pounds per cubic yard of concrete. Alternate products shall be preapproved by the city engineer in writing. Fibrillated and self-fibrillating fibers are specifically prohibited from use. Macro fiber dosage rate shall be:

Collector streets at 4.5 pounds per cubic yard of concrete.

Residential (minor streets) at three pounds per cubic yard of concrete.

(2)

All sidewalk and driveway pavement shall contain micro polypropylene fibers. These shall be applied to the concrete mixture at the rate of one and one-half pounds per cubic yard of concrete. Cellulose (treated or untreated), AR glass, nylon, and polyester fibers are specifically prohibited from use.

4.4.
Mixing and proportioning:

4.4.01. Ready mix concrete may be used provided it conforms to the requirements set forth herein and ASTM Specification C-94, latest revision.

4.4.02. Concrete shall be so proportioned as to give a minimum 28-day compressive strength of 4,000 psi. Water content shall not exceed the amount recommended by a testing laboratory and approved by the city engineer. Aggregates shall be batched by weight. Cement shall be measured by sacks or by weight and water shall be accurately measured by volume or weight. Slump to be no greater than 5½ inches.

4.4.03. Water will not be added on the job.

4.4.04. Only one brand of Portland cement shall be used throughout the entire job, unless specifically approved by the city. In no event shall more than one brand be used in the pour of any one day.

4.5.
Before placing concrete:

4.5.01. Placing shall not be commenced until sufficient subgrade is prepared and forms set. Concrete shall be placed with minimum rehandling and in one layer. The concrete shall be sliced and spaded while being placed. Particular attention shall be given to vibrating adjacent to forms and joints. Over-vibration or manipulation causing segregation shall not be permitted.

4.5.02. When forms have been securely set to grade, the base shall be tested as to cross section and elevations by means of template. The template shall be so constructed and operated to correctly indicate locations where the base does not conform the specified elevation and section. Low areas shall be brought to proper elevation by filling with approved material. Pavement shall not be placed on loose materials or a rutted base.

4.5.03. The base shall be saturated with water the previous night or not less than six hours prior to the placing of concrete. If it subsequently becomes too dry, the subgrade shall be sprinkled, but the method of sprinkling shall not be such as to form mud or pools of water.

4.5.04. Concrete shall not be placed on a frozen subgrade. No concrete shall be mixed while the air temperature is at or below 40 degrees Fahrenheit. Concrete shall not be placed unless the air temperature is at least 40 degrees Fahrenheit and rising. No materials containing frost or lumps of hardened materials shall be used. No concrete shall be placed around manholes or other structures until they have been brought to the required grade and alignment.

4.5.05. The roadway pavement shall be of the size and shape set forth in the plans including the integral curb, and consist of one course of Portland cement concrete with the addition of joints, dowels, etc., as called for in the plans.

4.5.06. Form work. Forms shall be so constructed and placed as to resist, without springing or settlement, the pressures of the concrete. When set to grade and stakes in place, the maximum deviation of the top surface from a straight line shall not exceed one-eighth inch and one-fourth inch in ten feet for the up- standing leg.

4.5.07. Forms shall be cleaned and oiled each time they are used.

4.5.08. Site mixing. The mixing of concrete shall be done in a batch mixer of approved type and size which ensure a uniform distribution of the materials throughout the mass, so that the mixture is uniform and homogenous. The equipment at the mixing plant shall be so constructed that all materials (including the water, admixture of fine sand, if used) entering the drum can be accurately proportioned and be under control. The entire batch shall be discharged before recharging. The volume of the mixed material per batch shall not exceed the manufacturer's rated capacity of the mixer. The mixing of each batch shall continue for the periods indicated below during which time the drum shall rotate at a peripheral speed of about 200 feet per minute. The mixing periods shall be measured from the time when all of the materials are in the mixer drum. Mixing time shall be as set out in subsections 4.5.09 and 4.5.10 below.

4.5.09. For mixers of a capacity of one cubic yard or less 1½ minutes.

4.5.10. For mixers of capacities larger than one cubic yard, the time of mixing shall be increased 15 seconds for each additional one-half cubic yard capacity or fraction thereof.

4.5.11. The mixer shall be thoroughly checked and calibrated before beginning operations and during mixing operations or at any time deemed necessary by the engineer. Equipment not in good operating condition shall not be used.

4.5.12. Central plant batching. Batching of materials in the desired proportions may be accomplished at a central plant when so approved by the engineer. When approved, the batching plant shall include batcher bins, either of the stationary or mobile types, with separate compartments for fine and coarse aggregates, each compartment designed to discharge freely and efficiently into the weighing hopper or hoppers. The scales for weighing aggregates shall be either the horizontal or the springless dial types, designed of rugged construction as an integral unit of the batching plant with a maximum allowable error of one-half percent of the net load and with significant gradation down to two pounds. The contractor shall maintain the equipment in good condition and adjustment and shall provide for accurate operation. If, for any reason, equipment previously approved becomes unsatisfactory, it shall be repaired or replaced before proceeding with the work.

4.5.13. Aggregates shall be transmitted from the batching plant to the mixer in batch boxes, vehicle bodies or other containers of adequate capacity and construction to properly carry the volume required. Cement in original shipping packages may be transported on the top of the aggregates, each batch containing the number of bags required by the "job mix". Batches shall be delivered to the mixer separately and intact, and each batch container shall be dumped cleanly into the mixer without loss of cement or mixing or spilling of material. Bulk cement may be used if necessary precautions to prevent loss in transit are taken. All vehicles carrying loose cement must be covered during transit with tarpaulin.

4.5.14. Mixing shall be accomplished as specified above for site mixing.

4.5.15. Central plant mixing. The use of a central mixing plant will not be permitted unless specifically approved by the city in writing. When such approval is given the concrete shall be mixed to such consistency that the hauling will cause no segregation of the constituent materials. The method of storing and hauling and equipment used shall be subject to the approval of the city. Vehicles used to transport the mixed concrete shall be equipped with suitable devices for slowly agitating the concrete during transit and for delivery of the concrete in an unsegregated condition of uniform consistency. Any vehicle load showing nonuniform consistency on arrival will be subject to rejection.

4.5.16. Transit mixing. Transit mixing will be permitted, provided that the requirements of ASTM specification C-94, latest edition are met.

4.6.
Placing concrete. Concrete shall not be placed until base has been conditioned as hereinabove specified. Base shall be moistened in advance of concreting, but shall not be muddy or excessively wet. The concrete shall be mixed in quantities required for immediate use and shall be deposited on the base to the required depth and width of the pavement section in successive batches and in a continuous operation without the use of intermediate forms or bulkheads between joints. While being placed, the concrete shall be spaded and compacted with suitable tools so that the formation of voids or honeycomb pockets is prevented. The concrete shall be especially well spaded and tamped against the forms and along all joints.

4.6.01. Concrete will not be dropped onto the base from such a height as to damage forms. The bucket or chute will be as close to the base as possible when the concrete is released.

4.6.02. At the end of a day's placement, or in the case of unavoidable interruption of more than a 30-minute period, a transverse joint shall be placed at the point of work stoppage; provided that the section on which the work has been suspended shall be not less than ten feet in length; sections less than ten feet in length shall be removed from the subgrade, and the removed concrete shall be disposed of from the job site.

4.7.
Working and finishing concrete. The sequence of operations shall be: First, "the strike-off and consolidation"; second, "longitudinal floating and removal of laitance"; followed by "straight edging," "belting" and final finish "brooming." All finishing equipment and tools shall be cleaned as often as required by the city.

4.7.01. Strike-off and consolidation. The concrete shall be distributed or spread as soon as placed. A mechanical concrete spreader may be used. The concrete shall then be struck off and screeded by vibration or means approved by the engineer. The striking off and screeding shall conform to the existing crown and cross section determined before removal of the existing pavement and shall be performed at such elevation slightly above grade that, when properly consolidated and finished, the surface of the pavement will be at the original elevation and free from porous areas.

4.7.02. Hand methods of strike-off and consolidation. Concrete, as soon as placed, shall be struck-off and screeded to the original crown and cross section determined before removal of the existing pavement and to such elevation above grade that when consolidated and finished, the surface of the pavement shall be at the grade elevation. A strike-off original template constructed to produce the pavement surface cross section indicated on the plans shall be provided for this work. It shall be rigidly constructed to retain its shape. In making the strike-off above mentioned, the template shall be moved always in the direction in which the work is progressing and so manipulated that neither end is raised from the side forms during the striking-off process.

4.7.03. Longitudinal floating. After the concrete has been struck off and consolidated it shall be further smoothed and consolidated by means of a longitudinal float, using one of the following methods.

4.7.04. Hand method. The hand-operated longitudinal float shall not be less than three feet in length and six inches in width, properly stiffened to prevent flexibility and warping. In this operation, a longitudinal float, operated from boot bridges resting on the side forms and spanning but not touching the concrete shall be worked with a sawing method motion, while held in a floating position parallel to the road centerline, and passing gradually from one side of the pavement to the other. Movement ahead along the centerline of the pavement shall be in successive advance of not more than one-half the length of the float. Any excessive water or soupy material shall be wasted over the side forms on each pass.

4.7.05. Mechanical method. The mechanical longitudinal floats shall be of a design approved by the engineer, and shall be in good working condition. The tracks from which the float operates shall be accurately adjusted to the required crown. The float shall be accurately adjusted and coordinated with the adjustments of the transverse finishing machine so that a small amount of mortar is carried ahead of the float at all times. The forward speed shall be adjusted so that the float will lap the distance specified by the engineer on each transverse trip. The float shall pass over each area of pavement at least two times, but excessive operation over a given area will not be permitted. Any excess water or soupy material shall be wasted over the side forms on each pass.

4.7.06. Brooming. As soon as the surplus water, if any, has risen to the surface, the pavement shall be given a broom finish. The broom shall be drawn from the center to each edge of the pavement with adjacent strokes slightly overlapping. The brooming operation shall be so executed that the corrugations produced in the surface will be uniform in appearance and not more than 1/16 of an inch in depth. Brooming shall be completed before the concrete is in such condition that the surface will be torn or unduly roughened by the operation. The surface thus finished shall be free from rough and porous area, irregularities and depressions, resulting from improper handling of the broom. Brooms shall be of the quality, size and construction and be so operated as to produce a surface finish meeting the approval of the engineer. Subject to satisfactory results and approval of the engineer, the contractor will be permitted to substitute mechanical brooming in lieu of the manual brooming as herein described. Brooms shall be maintained in good usable condition at all times by being washed thoroughly and dried at frequent intervals. Any course or long bristles which cause irregularities or deep corrugations shall be trimmed or entirely cut off. Brooms which have become worn or which are otherwise unsatisfactory for acceptable work shall be discarded.

4.7.07. Edging. After brooming has been completed, but before the concrete has taken its initial set, the edges of the slab shall be carefully finished with an edger of the radius required by the plans, and the pavement edge shall be left smooth and true to line.

4.8.
Curing. Curing shall be by an approved moist curing method or by spraying with an approved curing compound. Materials and methods used shall retain, after 72 hours, at least 90 percent of the original water in the mix, when tested by ASTM C-156. Curing will follow immediately after brooming.

4.8.01. Curing compounds. Impervious membrane curing compound: Curing compound shall be of a consistency suitable for spraying, shall be relatively nontoxic, and shall satisfactorily adhere to a horizontal surface of damp concrete when applied immediately causing the disappearance of surface water. The resultant film shall be continuous, uniform, free from pinholes, moisture, impermeable and shall not react with the components of concrete. The compound shall be supplied with a fugitive dye, which shall show no indication of its use in 15 days. When the compound is applied to test specimens, at a rate of coverage recommended by the manufacturer for one application, the specimens shall not lose more than the maximum amount of moisture as follows:

At 24 hours ..... 2.5%

At 72 hours ..... 5.5%

At 7 days ..... 7.0%

4.8.02. The compound shall be dry to touch on a damp horizontal concrete surface in not more than two hours at a temperature of 75 degrees Fahrenheit when applied at a rate of coverage recommended by the manufacturer.

4.8.03. Membrane curing compound pigmented. Curing compound shall comply with all requirements hereinabove contained and in addition, shall meet the following specific requirements.

4.8.04. The compound shall be a white pigmented type.

4.8.05. The compound when applied to a new concrete surface at the specified coverage, shall provide a uniform white appearance and shall effectively obscure the original color of concrete. After the compound has dried it shall have an apparent daylight reflectance of not less than 60 as determined by Method 612 of Federal Specifications TT-P-14LA. The compound shall have a hiding power of not less than eight square feet per gallon when tested in a manner as stated in part 3, division 11, paragraph 5.21 of the Standard Specifications for Roads and Bridges, State of Louisiana, Department of Highways, July 1955.

4.8.06. Regardless of the coverage per drum of compound stated by the compound manufacturer, the concrete surface will be satisfactorily covered.

4.9.
Form removal.

4.9.01. Form removal shall be carefully done without damage to green concrete and not before 12 hours after placing. Holes, voids, or honeycombs shall be filled with 1:2 mortal and floated smooth. Expansion joints shall be cut free of concrete. Edges shall be protected by earth, planking or membrane curing compound pigmented as specified above immediately after form removal.

4.10.
Joints. Joints shall be cleaned of foreign matter and filled with an asphalt filler to within one-quarter inch of the top.

4.11.
Cleanup.

4.11.01. Prior to acceptance of the work by the engineer, the contractor shall clean all dirt, trash or superfluous matter from the finished roadway.

4.12.
Testing.

4.12.01. Two cylinders for each 50 cubic yards of concrete in place, or for each 100 linear feet of street placed or from each day's placement (whichever shall be similar) plus two beams for every 200 cubic yards of concrete placed or from each day's pour (whichever shall be smaller) shall be taken in accordance with ASTM C-31.

4.12.02. One of each pair of cylinders or beams taken shall be tested at seven days and one at 28 days.

4.12.03. In addition to the tests hereinabove mentioned, if evidence of faulty workmanship exists, violation of specifications, or likelihood of the use of faulty material, tests may be required, which may be made under the direction of the engineer. The costs of such tests shall be paid for by the contractor if the contractor is required to replace any concrete or if the concrete is inferior to that specified.

4.13.
Inspection.

4.13.01. Final inspection shall be made in accordance with the general conditions. The pavement shall be clean.

4.13.02. Opening for traffic. The contractor has full responsibility for his pavement until it is accepted by the engineer. The contractor must place suitable barricades of sufficient size and weight to prevent easy removal, across all accesses to the unaccepted pavement.

4.13.03. The use of unaccepted pavement by the contractor, any of his subcontractors, the public or the city before it conforms with the strength requirements of paragraph 4.13.04 below is prohibited without written permission of the city and the violation of same either through direct intent on the part of the contractor or by others due to the failure of the contractor to sufficiently prevent access, may prevent final acceptance by the engineer.

4.13.04. The pavement can be opened to all traffic when the results of the 28-day cylinder tests show the concrete has the required strength. The pavement can be opened to light traffic when test results indicate 75 percent or 3,000 psi of the desired strength has been obtained and then only upon the permission of the engineer.

4.13.05. The city reserves the right to open the pavement to traffic or to prohibit the opening to traffic at an age other than specified above, if, in the opinion of the city engineer, physical conditions warrant.

4.13.06. The same strength requirements govern concrete made with Type III cement.

4.13.07. Concrete curbs shall be cast integrally with the pavement in conformity with the appropriate detail shown on the plans. If cast integrally, the strike-off template must be designed to accommodate the curb, and the pavement must be painted with a neat cement paste of six gallons of water to one sack of cement immediately before casting the curb. Concrete for curbs must conform to the specifications above for pavements.

4.14.
Drilled dowels.

4.14.01. Where the existing doweling or hardware remaining in a portion of pavement is not satisfactory to the city engineer, he shall direct its removal and replacement with drilled and grouted dowels.

4.14.02. Removal of existing hardware shall be at the option of the city engineer and shall be accomplished without destruction of pavement to remain. Damage to pavement to remain will be repaired by the contractor in a manner acceptable to the city engineer, and at the expense of the contractor.

4.14.03. Dowels shall be #4 reinforcing bar of any steel listed in ACI 318-71, installed as shown on the plans, or an equivalent item specifically manufactured for the purpose and acceptable to the city engineer.

4.14.04. Drilling shall produce a hole three-fourths of an inch in diameter and at least 12 inches deep in the existing pavement, centered in the thickness of the existing slab.

4.14.05. Dowels shall be grouted into the drilling hole with a neat-cement grout to six gallons of water to one sack of cement. The hole shall be filled with grout and the dowel inserted in such a manner as to ensure that no voids exist.

4.15.06. Where required, dowels shall be placed on 12-inch centers.
(Amended 6-26-1979; Ord. No. 3021, 8-28-2001; Ord. No. 3525, 2-17-2009)