Construction Manual  

 

SECTION 710 - 2018 STANDARD SPECIFICATIONS

2018 STANDARD ROADWAY DRAWINGS

710-1 DESCRIPTION

This section of the Specifications expands on the general requirements of Section 700 and gives the specific details and requirements for concrete pavement construction. While these Specifications will apply to most non-reinforced, jointed pavements with dowels, project personnel should always refer to the plans and Project Special Provisions for exceptions to the Standard Specifications.

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710-2 MATERIALS

The specifications for concrete pavement materials are detailed in Division 10 of the Standard Specifications.

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710-3 COMPOSITION OF CONCRETE

Concrete pavement mixes are designed by the Contractor and submitted through the Engineer to the Materials & Tests Unit for review and approval. Article 1000-3 of the Standard Specifications details the various requirements for these mixes and the supporting data that the Contractor must supply.

 

The Strength-Maturity curve should also be submitted with the Concrete Mix Design and the other required information (See 700-13 in the Standard Specifications).

 

Prior to submitting a proposed mix to the Materials & Tests Unit, the Engineer should satisfy himself that all of the information required for evaluating the mix has been furnished. On most concrete paving projects, more than one mix will be required due to the use of hand-placement methods, early strength requirements, or other factors. The Engineer should be thoroughly familiar with the requirements of the project and have readily available any information required relating to job mixes.

 

The Engineer and the Contractor should pay close attention to those quarries whose aggregates are known to exhibit ASR characteristics. These quarries are listed on the Materials and Tests Unit’s website. When a concrete mix design contains aggregates from one of these listed quarries, the design should also include a pozzolan, such as fly ash, GGBFS, or Microsilica in the amounts listed in Article 1024-1, to inhibit the potential ASR problems.

 

The adjustment of mix designs when necessitated by low compressive strength is a critical factor, and the Engineer should notify the State Construction Engineer and Contractor immediately upon failure of the initial test beams to meet Specification requirements. The failure of a series of test cylinders to meet Specification compressive strength requirements at any time during production may indicate faulty testing procedures or a change in materials, and immediate checks and tests to determine the source of the deficiency should be made.

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710-4 ACCEPTANCE OF CONCRETE

Acceptance testing and sampling of the concrete mix is the responsibility of the Engineer. The Contractor is required to furnish the materials to be sampled and tested. The Specifications outline several areas where the Engineer will perform acceptance testing.

 

Assistance in determining the correct procedures and frequency of testing can be found by contacting the Materials & Tests Unit. Also, refer to Article 700-15 for more details on compressive and flexural strength sampling and testing requirements.

 

When the average of the Department’s compressive strength test results are below 4500 psi, the Engineer will perform an investigation.

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710-5 CONSTRUCTION METHODS

Concrete pavement will be constructed in accordance with the provisions of Section 700.

 

Concrete pavement should be placed in 2-lane minimum widths; however, there are a few exceptions noted. Refer to the plan details for joint locations and spacing, lane widths, etc., when large areas of concrete pavement are to be constructed, such as parking lots, in rest areas, weigh stations, etc.

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710-6 FINISHING

The concrete in front of finisher float machine screeds should be rolling, not sliding. (If not rolling, check to ensure that air-entrainment and slump meet specifications.) The first screed on the first pass should carry a uniform roll of concrete 6 to 8 inches in diameter and leave the concrete surface slightly high. The second screed on the first pass should carry a uniform roll of concrete 3 to 4 inches in diameter and cut the concrete to slightly above the level of the top of form. The forward screed should be tilted slightly to provide compaction and surge. Increasing the speed of transverse motion in relation to the forward motion usually eliminates tearing. Spreader and screeds shall operate continuously over the joints without disruption or lifting of the screed. For a good finish without bumps the paver should move continuously throughout the days operation with little or no stopping.

 

Experience has shown that supplemental finishing will be required for the concrete pavement to meet rideability requirements. This supplemental finishing may be accomplished either by an automated float attached to the paver or a tube machine. Except in areas not readily assessable to pavers and finishing machines, the use of straight edges for finishing operations shall be held to the minimum necessary. Proper finishing is the necessary step in the paving process in order to obtain the desired ride quality. The Technician should observe the Contractor’s finishing methods and techniques so that he may be in a better position to insist on appropriate corrective action if the final surface testing described later in this section of the Manual indicates a need to do so.

 

The use of excessive water during the finishing operations will not be permitted as this may cause the top surface of the concrete to have a weaker strength and potentially scale or spall off early in the pavement’s service life.

 

It is the Contractor’s responsibility and the Department’s objective to produce a quality pavement surface that will give a favorable ride without the use of grinding. Project personnel must insist that this objective be carried out by the Contractor even if it means stopping the paving operation until the problem can be corrected. When necessary, the Engineer should notify both the Division Engineer and the State Construction Engineer. The Contractor should not be allowed to continue paving when poor rideability is being achieved or excessive grinding is being required.

 

The final operation to obtain the desired surface texture is that of grooving the surface. This involves the movement of steel tines either transversely across the pavement surface while it is still in a plastic state in order to scratch small grooves in the pavement surface or by longitudinal tining. This will improve the skid resistance of the pavement and reduce the hydroplaning affect to vehicles in inclement weather by providing channels for the surface water to run off the pavement surface toward the shoulders. The PCCP Roadway Technician should monitor this tining operation to ensure that the Contractor’s timing for performing the transverse grooving is appropriate to achieve the desired results. If the Contractor is attempting to tine the pavement too early, the steel tines will have a tendency to drag some aggregate out of the surface, or the depth of the tines will be greater than the required depth. Conversely, if the tining is done too late, the grooves may not be deep enough and grinding of the pavement will be required to provide enough skid resistance. In addition, checks should be made to prevent the overlapping of adjacent grooving and to minimize the blank areas between passes. The Technician should refer to the plans and/or standard drawings for specific details on tine dimensions, location relative to edge of pavement, etc.

 

The Contractor will provide a textured surface with an average texture depth of 0.8 mm as tested in accordance with ASTM E 965 (Test Method for Measuring Pavement Macrotexture Depth Using a Sand Volumetric Technique) with no single test having a texture depth of 0.5 mm or less.

 

The Contractor will perform four randomly located tests in accordance with ASTM E 965 within the initial pavement lot of each mobilization and provide test results to the Engineer. A lot is defined in Article 710-4. If the average of the four tests does not meet the above criteria, make appropriate changes to the surface texture operations and test the next lot as detailed above. Once the surface texture process is established to meet minimum texture requirements, maintain consistency within the operation to provide the above minimum texture depth. Perform additional sand patch tests in accordance with ASTM E 965 when directed.

 

Should the surface texture become damaged or reduced by rain, grinding or any other action, reestablish or restore surface texture by an approved method.

 

Once the pavement has hardened, checks of the tining depth can be made to determine compliance with Article 710-6 describes the procedure required to check the depth of the texture.

 

The depth of the texture is important. The grooves are constructed to break the plain surface and thereby prevent hydroplaning. But, the grooves can create a noise problem.

 

In order to minimize the noise from the pavement surface, the tine depths shall be as shallow as possible within the specifications. This will insure safety but minimize any objectionable noise.

 

The apparatus needed to perform ASTM E 965, “Test Method for Measuring Pavement Macrotexture Depth Using a Sand Volumetric Technique” is as follows: