The Table of Contents for this section is available.
The work covered by this section consists of the construction of a single course non-reinforced portland cement concrete pavement on a prepared base in accordance with these specifications and with the lines, grades, thickness, and typical sections shown on the plans or established by the Engineer.
The concrete paving will be accepted with respect to strength and thickness on a lot by lot basis and subject to adjusted unit prices as provided in Sections 710 and 720.
The Contractor may use any combination of equipment which will effectively perform the necessary construction operations. The equipment shall be at the job site sufficiently ahead of the start of construction operations to be examined thoroughly and approved by the Engineer.
All equipment shall be maintained in a satisfactory operating condition by the Contractor while in use on the work.
700-2 CONCRETE PRODUCTION EQUIPMENT.
The requirements for the batch plant, central mix plant, and truck mixers shall be in accordance with Section 1000.
700-3 CONCRETE HAULING EQUIPMENT.
When central mixed concrete is used, non-agitating hauling equipment may be used to transport the concrete. Bodies of equipment shall be smooth, water-tight, metal containers equipped with gates and vibrators that will permit control of the discharge of the concrete.
The concrete shall be delivered to the site of the work in a thoroughly mixed and uniform mass and discharged with an acceptable degree of uniformity.
Delivery time is defined as the elapse time from the time water is added to the mix until it is deposited on the grade. When using central mixed concrete, the maximum delivery time shall be 30 minutes when hauled in non-agitating trucks and 60 minutes when hauled in mixing or agitator trucks.
700-4 PREPARATION OF SUBGRADE AND AGGREGATE BASE.
The subgrade and aggregate base beneath Portland cement concrete pavement shall be prepared in accordance with the applicable sections of these specifications except that the Contractor shall use an approved automatically controlled fine grading machine to produce final subgrade and aggregate base surfaces meeting the lines, grades, and cross sections required by the plans or established by the Engineer. When in the judgment of the Engineer the use of such equipment is impracticable, this requirement will be waived.
The surface of the aggregate base shall be damp at the time the concrete is placed. The Contractor shall sprinkle the base when necessary to provide a damp surface. The Contractor shall satisfactorily correct all soft or damaged areas in the subgrade or base prior to placing concrete.
Hauling over the base course will not be allowed except where specifically permitted by the special provisions or in writing by the Engineer. The Engineer may allow equipment dumping concrete to operate on the base to the extent and under the conditions the Engineer deems necessary to facilitate placing and spreading the concrete.
(A) General:
A slip form paver shall be used to place concrete except where its use is impractical due to the presence of irregular areas or areas of existing pavement adjacent to the proposed pavement, or where otherwise permitted by the Engineer.
Concrete shall be placed only in the presence of the Engineer or his authorized representative.
Concrete shall be handled in such a manner as to prevent segregation and kept free from mud, soil, or any other foreign matter.
Where finishing operations must be completed after dark, artificial light acceptable to the Engineer shall be provided by the Contractor.
Paving operations shall not be undertaken or shall be discontinued when any of the following conditions exist:
1. When a descending air temperature in the shade and away from artificial heat reaches 40F, paving shall be stopped. Paving shall not be resumed until an ascending air temperature in the shade and away from artificial heat reaches 35F.
2. When the subgrade or base course is frozen.
3. When aggregates to be used in the mix contain frozen particles.
4. When air temperature in shade is 95°F and rising or the concrete temperature is greater than 95°F.
Where additional pavement must be placed adjacent to new pavement by machine methods, it shall not be placed until representative test beams of the concrete have attained a flexural strength of at least 450 psi.
Construction equipment or hauling equipment will not be allowed over the pavement until representative test beams of the concrete have attained a flexural strength of 550 psi.
(B) Slip Form Paver Method:
Where a slip form paver is to be used, the concrete shall have sufficient cohesion to prevent appreciable slumping of the pavement edges. When the original mix design produces a concrete which will not meet these requirements, production shall be stopped or slowed and corrections to the mix shall be immediately made.
The slip form paver shall be an approved self-propelled machine(s) designed to spread, consolidate, screed, and float finish the concrete in one complete pass of the machine in such a manner that a minimum of hand finishing will be necessary to provide a dense and homogeneous pavement. The machine shall vibrate the concrete for the full width and depth being placed. The vibration shall be accomplished internally by vibrating tubes or arms working in the concrete or with a vibrating screed or pan operating on the surface of the concrete. The slip form paver shall be equipped with forms of sufficient length and rigidity to adequately support the edges of the slab so as to permit any necessary hand finishing. The slip form paver shall be equipped with and utilize automatic controls for both horizontal and vertical control. These automatic controls shall be checked daily by the Contractor and be working properly prior to beginning the days operations.
The paver shall be operated with a continuous forward movement and all operations of mixing, delivering, and spreading the concrete shall be coordinated to provide uniform progress with stopping and starting of the paver held to a minimum. If for any reason it is necessary to stop the forward movement of the paver, the vibratory and tamping elements shall also be stopped immediately.
Surface smoothness and texture shall meet the requirements of Article 7106 and Article 7107 except that a longitudinal straight edge tolerance of 1/4 inch in 10 feet will apply to the area within 6 inches of the edge of pavement. The maximum acceptable edge slump shall be 1/4 inch.
In addition to the requirements of Article 7008 the Contractor shall have available at all times materials for the protection of the edges of the unhardened concrete. Such protective materials can be either standard metal forms, or wood plank having a nominal thickness of not less than 2 inches and a depth equal to at least the thickness of the pavement. When rain appears imminent, all paving operations shall stop and all available personnel shall assist in protecting the unhardened concrete.
(C) Fixed Form Method:
The requirements of this subarticle shall apply to all paving operations where a slip form paver is not being used.
Forms shall be metal and of such section and design that they will adequately support the concrete and the construction equipment.
Forms shall have a depth not less than the edge thickness of the pavement to be constructed and not more than 1 inch greater than the edge thickness of the pavement to be constructed. The base width shall be at least equal to the height of the form.
The top face of the form shall not vary from a true plane more than 1/8 inch in 10 feet, and the upstanding leg shall not vary more than 1/4 inch.
Straight forms 10 feet in length shall have at least 3 pin pockets. Straight forms 5 feet in length shall have at least 2 pin pockets.
Form pins shall be metal and shall be capable of holding the forms rigidly in place during construction operations. The Engineer may require pin holes in the base to be sealed prior to placing subsequent pavement.
The form sections shall be connected by a locking joint which shall keep the forms free from vertical and horizontal movement.
Straight forms 10 feet in length shall be used on tangents and on curves having a radius of 200 feet or more. Forms for curves having a radius of between 200 feet and 50 feet may be either straight forms 5 feet in length or flexible forms. Forms for curves having a radius of less than 50 feet shall be flexible forms.
All forms shall be thoroughly cleaned before being set and shall be thoroughly oiled before any concrete is placed. The bearing of the forms shall be checked and all areas of inadequate bearing shall be corrected.
All rejected forms which are not satisfactorily corrected immediately shall be removed from the project by the Contractor.
Forms shall be set a sufficient distance in advance of the point where the concrete is being placed to provide for a continuous operation in placing the concrete and for proper inspection of line and grade.
All forms used for construction joints shall meet the requirements of this subarticle except that provisions shall be made for inserting dowel bars where required.
700-6 SPREADING AND VIBRATING CONCRETE:
The concrete shall be spread uniformly over the entire area between the forms without segregation. Spreading shall be done with a mechanical spreader except where hand methods are necessary due to pavement design, equipment breakdown, or other emergency.
After the concrete has been spread it shall be uniformly vibrated. Vibrators for full width vibration of concrete paving slabs may be either the surface pan type or the internal type with either immersed tube or multiple spuds. They may be attached to the spreader or the finishing machine, or may be mounted on the separate carriage. They shall not come in contact with the joint, load transfer devices, subgrade, or side forms. Machine mounted vibrators shall be either stopped or removed from contact with the concrete whenever the forward motion of the machinery is stopped. The frequency of the surface vibrators shall not be less than 3,500 impulses per minute and the frequency of the internal type shall not be less than 5,000 impulses per minute for tube vibrators and not less than 7,000 impulses per minute for spud vibrators.
When spud type internal vibrators, either hand operated or attached to spreaders or finishing machines, are used adjacent to forms, they shall have a frequency of not less than 3,500 impulses per minute.
Finishing of the concrete pavement or concrete shoulders shall be in accordance with Article 7106 or Article 7207, respectively.
700-8 PROTECTION FROM COLD WEATHER AND RAIN.
Concrete less than 72 hours old which may be subject to damage by freezing shall be adequately protected with insulating materials such as burlap, plastic sheets or other materials as approved by the Engineer, until the concrete reaches an age of 72 hours. Concrete damaged as a result of freezing shall be removed and replaced by the Contractor at no cost to the Department. When flyash is used, the protection period shall be not less than 7 days.
Protective covering which will protect the surface of the freshly placed pavement from rain shall be readily available each day at the location of each proposed day's operation prior to beginning work. An adequate quantity of these materials shall be stored at the paving train. Concrete damaged as a result of failure on the part of the Contractor to adequately protect the concrete from rain shall be repaired or removed and replaced by the Contractor as directed by the Engineer at no cost to the Department.
(A) General:
Immediately after finishing operations have been completed and surface water has disappeared, all exposed surfaces of the pavement shall be cured by one of the methods covered by this article, unless otherwise approved by the Engineer.
The selected curing method shall be applied to the edges of the pavement immediately after the forms are removed.
The total curing period required shall be 3 curing days for all methods. A curing day will be considered as any consecutive 24 hour period, beginning when the manipulation of each separate mass has been completed, during which the air temperature adjacent to the mass does not fall below 40°F.
(B) Membrane Curing Compound:
The minimum rate of application shall be 1 gallon per 150 square feet when the application equipment is mechanically operated or 1 gallon per 100 square feet when the application equipment is hand operated.
Mechanically operated application equipment shall be designed to apply a uniformly agitated continuous flow of the curing compound at the prescribed rate to all concrete surfaces.
The membrane curing compound film shall be protected at all times and any damage shall be immediately repaired. The Contractor shall keep available a sufficient amount of polyethylene film, burlap, or other approved material to provide for protection of the concrete during rain or when the application equipment fails to apply the curing compound uniformly to all surfaces.
(C) Polyethylene Film:
The sections of the film shall be spread in a manner which will prevent damage to the finished pavement surface. Lap joints of the sections shall be at least 12 inches wide and suitable precautions shall be taken to prevent the circulation of air beneath the film.
The film shall be checked for damage when it is spread and while in use and any damaged sections shall be immediately repaired or replaced.
(D) Burlap:
The sections of burlap shall be spread in a manner which will prevent damage to the finished pavement surface. Lap joints shall be at least 6 inches wide.
The amount of burlap to be used shall be not less than 12 ounces per running yard based on a 40 inch width and may be either 1 layer of Class 4 burlap or 2 layers of Class 1, 2, or 3 burlap.
The burlap shall be thoroughly saturated prior to placing on the concrete and shall be kept thoroughly wet throughout the curing period.
Forms shall not be removed from freshly placed concrete until is has hardened sufficiently to resist spalling, cracking, or any other damage, but in no case until at least 12 hours after the concrete has been placed. Any honey-combed areas along the sides or edges of the slab shall be repaired by filling with mortar immediately after the forms have been removed. The mortar shall be completed (See Standard Special Provisions) of 1 part of cement to 2 parts of fine aggregate.
(A) General:
All joints shall be constructed in accordance with the requirements of these specifications and the details shown on the plans. All joints shall be sawed and sealed with joint sealer in accordance with the dimensions and details shown on the plans. Joints shall be sealed in accordance with the provisions of Article 70012.
Sawing to the full depth required by the plans to control random cracking shall be done as soon as the concrete has hardened sufficiently to be sawed without spalling and raveling but not more than 24 hours after the concrete is placed.
The additional sawing necessary to provide the full joint width required by the plans shall be done no earlier than 10 days prior to the sealing of the joint.
Deviations from the method of joint construction required by the plans or specifications may be permitted provided prior approval has been obtained in writing from the Engineer. Such approval will be considered conditional and will be subject to obtaining satisfactory results.
If the Contractor desires to utilize any construction techniques not shown on the plans to minimize potential cracking, permission shall be obtained in writing from the Engineer prior to beginning the affected work.
The Engineer may order any concrete pavement or shoulder where uncontrolled cracking has occurred prior to final acceptance to be removed and replaced at no additional cost to the Department. Where permitted by the Engineer, the Contractor may be allowed to repair the cracking in a manner acceptable to the Engineer.
Prior to placing either concrete pavement or concrete shoulders adjacent to a previously placed pavement, the transverse joint opening on the edge of the existing slab shall be covered with tape or other approved method to prevent intrusion of grout into the opening.
(B) Transverse Contraction Joints:
Transverse contraction joints shall be constructed in accordance with the details, dimensions and intervals as shown on the plans.
(C) Longitudinal Contraction Joints:
Longitudinal contraction joints shall be constructed in all pavements wider than 16 feet in accordance with the details and dimensions shown on the plans, and shall be formed by sawing with an approved concrete saw.
(D) Transverse Construction Joints:
(1) General:
Transverse construction joints shall be constructed by use of an approved form at the end of each day's operations (planned joint) or whenever the placing of concrete is suspended for more than 30 minutes (emergency joint).
(2) Planned Transverse Construction Joints:
This type joint shall be located at the same spacing required for contraction joints. Dowel bars of the size and spacing shown on the plans shall be used.
(3) Emergency Transverse Construction Joints:
This type joint shall be used when the placing of concrete is suspended for more than 30 minutes. Tie bars of the size and spacing shown on the plants shall be used.
The spacing of contraction joints shall not be changed due to emergency construction joints and the emergency construction joints shall not be located less than 6 feet from any contraction joint or planned construction joint.
Emergency transverse construction joints shall be sawed and sealed in the same manner as required by the plans for planned transverse construction joint.
(E) Longitudinal Construction Joints:
Longitudinal construction joints shall be constructed by the use of tie bars in accordance with the details shown on the plans.
(F) Transverse Expansion Joints:
Transverse expansion joints shall be constructed in accordance with the details shown on the plans utilizing an approved joint assembly.
(A) General:
All joints shall be sealed with low modulus silicone sealant in the presence of the Engineer's representative.
Backup material and sealant shall be installed in accordance with the details shown in the plans and the manufacturer's recommendations.
Any failure of the joint material will be cause for rejection, and the joint shall be repaired as approved by the Engineer at no cost to the Department.
When requested by the Engineer, the Contractor shall have a representative of the silicone sealant manufacturer present of the project during the sealing operation.
(B) Age of Pavement:
The concrete shall be at least 14 calendar days old before the joints are sealed.
Final sawing and sealing of concrete pavement joints shall not be performed until after surface testing, correction of surface deficiencies, and all adjacent earth and paved shoulder construction have been completed.
(C) Temperature:
Joint sealer shall not be placed when the air temperature near the joint is less than 45F. or is 45F. and falling, unless otherwise authorized by the Engineer.
(D) Sealing the Joint:
Immediately after sawing the joint to the dimensions as shown on the plans, the resulting slurry shall be completely removed from the joint by flushing with a jet of water under pressure. Sand blasting shall be used to clean joint faces before joints are sealed. As many passes with a sand blaster as are necessary shall be made to provide a clean joint wall. After cleaning, the joint shall be thoroughly dry at the time of sealing.
All joints shall be blown clear of deleterious materials with air using a nozzle pressure of at least 90 psi before installing the backer rod. Rotary screw compressors shall be used for this purpose and shall be equipped with traps capable of removing water and oil from the air. Traps shall be maintained in accordance with manufacturer's instructions.
The sealer shall be placed to reasonably close conformity with dimensions shown on the plans. Any unreasonable deviation will be cause for rejection.
(E) Cleaning Pavement:
After a joint has been sealed, surplus joint sealer on the pavement shall be removed as soon as possible. The pavement shall not be opened to traffic before surplus joint sealer has been removed and the sealant has cured in accordance with the manufacturer's recommendations.
700-13 USE OF NEW PAVEMENT OR SHOULDER.
Traffic or other heavy equipment will not be allowed on the concrete pavement or shoulder until representative test samples have attained a flexural strength of at least 550 psi.
The Contractor is responsible for anticipating the need for early breaks on beams due to placing additional pavement adjacent to new pavement, the need to operate mixing and hauling equipment on pavement, and the need to permit traffic on pavement, prior to the routine acceptance testing of beams at 14 calendar days. The Contractor is also responsible for making the additional beams for testing prior to 14 calendar days. The minimum number of sample tests required when early use of the pavement is requested is 2 sets of 2 samples for each day's operation. The Engineer will test the beams as requested by the Contractor.
No permanent traffic will be allowed on the pavement until construction of the joints, including all sawing and sealing that is required, has been completed.
Construction traffic will be permitted on pavement which has reached the required strength. No traffic will be permitted on the pavement after the final sawing of the joint until the joints are sealed and the sealer is tack free.
Particular care shall be taken to protect the exposed pavement edges and ends.
700-14 CONTRACTOR'S RESPONSIBILITY FOR PROCESS CONTROL.
Process control sampling and testing of concrete materials and operations shall be performed by the Contractor in accordance with the provisions of Article 10003.
700-15 ACCEPTANCE TESTS FOR CONCRETE.
(A) Responsibility:
Acceptance sampling and testing of concrete will be conducted by the Engineer. The Contractor shall provide access to all materials to be sampled and tested. The following tests will be performed on both concrete pavement and concrete shoulders to determine acceptance.
(B) Lot Definition:
(1) Definition of Lot:
A lot for acceptance purposes will be as defined as described in Article 7104 and 7204 for concrete pavement and concrete shoulders, respectively.
(2) Exception For Partial Lot:
When operational conditions, such as a new mix design, lengthy interruptions in paving, or project completion, cause a lot to be terminated with less than the specified lot size, the following procedure will be used for acceptance:
If less than 3 sublots have been completed, the square yards of pavement placed and the test results of the beams made will be combined with the most recently completed lot, and acceptance of the combined total square yards will be based on the average of the test results in the revised lot.
If at least 3 sublots have been completed, but the full lot has not been completed, the lot size will be considered as the number of square yards placed and the lot will be accepted on the basis of the average result of the beam tests made.
(C) Air Content:
The air content of the concrete will be determined on the roadway at a frequency established by the Engineer, and in accordance with Subarticle 10003(B). The sample taken for determination of air content will be obtained immediately after the concrete has been discharged on the road.
Concrete failing to meet specification requirements for air content will be subject to rejection.
(D) Slump:
The slump of the concrete will be determined in accordance with AASHTO T119 at a frequency established by the Engineer. The sample taken for determination of slump will be obtained immediately after the concrete has been discharged onto the road.
When the slump of the concrete is questionable by visual observation, it shall not be placed on the road until tested for slump by the Engineer.
Concrete failing to meet specification requirements for slump will be subject to rejection.
(E) Flexural Strength:
The flexural strength of concrete will be determined by testing 6"x6"x20" beams at 14 calendar days. Test beams for determining the flexural strength of the concrete will be made by the Engineer from the concrete as it comes from the mixer. The beams will be made and cured in accordance with AASHTO T23 except that immersion in saturated lime water will not be required. Beams will be tested by the Engineer in accordance with AASHTO T97. The Contractor shall furnish curing facilities for the test beams in accordance with Section 725.
Each lot will be divided into 4 equal sublots and from each sublot a set of two 6"x6"x20" beams will be made from a randomly selected batch of concrete. The average flexural strength of the 2 beams from each sublot is considered one test. The pay factor for each lot will be based on the average of the test results of the 4 tests.
(1) Outlier Check:
The test results for each lot will be checked for outliers by the following procedure (outlier- an extreme individual test that is to be discarded):
1. Tabulate the test results (X), add them to obtain the sum, and divide this sum by the number of test results (N) to obtain the Mean (X) or Lot Average.
2. Obtain the difference between each test result and the Mean, square each difference, and add the results to obtain the sum of the square of the differences.
3. Divide the sum of the squares of the differences by the number of measurements, less one.
4. Find the square root of the value obtained in Step 3 above. This gives the Standard Deviation for the lot.
5. Divide the difference between the Mean obtained in Step 1 above and the test result in question by the Standard Deviation obtained in Step 4 above. This gives the T value.
6. If the T value (disregarding algebraic sign) obtained in Step 5 above exceeds the Critical T value listed below and no assignable cause can be determined for the test result in question, discard this test result.
Number of Observations, N Critical T Value
3 1.15
4 1.48
5 1.71
6 1.89
7 2.02
8 2.13
(2) Average Flexural Strength:
The average flexural strength and the range R will be computed for the test results of each lot. The range R is the difference between the high and low tests in the lot (a test is considered the average strength of the 2 samples in each sublot). If the average strength of the lot acceptance tests equals or exceeds the lower acceptance limit shown in Table 7101 for a pay factor level of 1.00, the lot will be accepted without any reduction in contract price. If the average strength of the lot acceptance tests fail to attain the lower acceptance limit for a pay factor level of 1.00, the Contractor will have the option of replacing all concrete in the lot or leaving it in place at a reduced contract price determined in accordance with Subarticle 71012(C) (See Standard Special Provisions) or 72011(C). If the average of the lot acceptance tests fails to attain the lower acceptance limit for a pay factor level of 0.70, the Engineer may require the removal of any or all concrete in the lot. Any such concrete permitted to remain in place will be paid for at a pay factor level of 0.50.
(F) Thickness:
The thickness of the pavement will be determined by measurement of cores tested in accordance with AASHTO T148 as modified by the Department. Copies of the modified test procedures are available upon request from the Construction Unit.
The cores shall measure at least 4 inches in diameter and shall be taken by the Contractor in the presence of the Engineer. Cores shall be taken no earlier than 15 days and no later than 30 days after the pavement has been placed. The core locations for each sublot in a lot will be selected at random by the Engineer.
All core holes shall be patched by the Contractor within 72 hours of taking the core, using a concrete mixture compatible with the pavement or shoulder concrete.
(G) Surface Smoothness:
Acceptance testing for surface smoothness on concrete pavements
shall be in accordance with Article 7107.