- 393 - SECTION 601 -- GENERAL REQUIREMENTS
601.01 General
1.This Section describes materi als, procedures and equipment that are common to items of work described in Division 600. The requirements in
2.The Contractor shall protect concrete pavement from any damage including but not limited to damage due to precipitation or freezing conditions.
3.The Contractor shall replace any concrete damaged by precipitation, freezing, or other conditions at no additional cost to the Department.
4.The Contractor shall always have materials readily available to protect the surface and t he edges of the concrete.
5.No section of concrete pavement will be opened to traffic without providing the Engineer adequate advance notice to inspect joints, check the pavement surface, and schedule the coring unit.
6.The method used to place concrete shall not allow the concrete materials to segregate or displace rein forcing steel. The impact of any free fall must be kept to the lowest levels consistent with efficient placement.
7.Curing compounds shall not be placed on any surface that will be bonded to another concrete surface.
8.The Department is responsible for the initial cores on all Portland cement concrete pavement.
601.02 Equipment
1.a. All placing and finishing equi pment shall be at the job site one full NDOT work day before its intended use to allow the Engineer time to examine it.
b.On small urban projects, the equipment will be examined before the work starts. However, the equipment need not be on site 1 day before the paving.
2.Garden rakes shall not be used to handle or move concrete. 3. Equipment shall meet t he requirements of Section 1002.
4.The subgrade profiling equipment shall be capable of meeting the Construction methods of Section 302. Electronically controlled profiling equipment will not be required when subsequent construction uses formed construction methods.
5.Concrete spreaders shall be self-propelled and able to spread and strike off concrete. The spreader may be an independent machine or combined with the finishing machine. Mechanically drawn strike off blades shall not be employed unless hand finishing methods are allowed. Self-propelled concrete spreaders shall be equipped with the following devices:
a.A power-driven system capable of uniformly spreading the concrete transversely without segregation.
b.An adjustable strike-off screed capable of leveling the concrete surface at the required elevation inside the forms.
601.02 General Requirements
- 394 - c. Vibrators capable of unifor mly consolidating the full depth and width of the concrete.
6.a. Concrete pavement finishing machines shall be self-propelled and capable of leveling, consolidat ing, and floating the concrete.
b.The finishing machine shall travel at a controlled speed such that it produces a uniform, well conso lidated pavement that does not contain large voids or torn pavement.
c.All finishing machines shall finish the pavement to the required cross section.
7.All spreading and finishing equipment operating on forms shall be equipped with scrapers to keep the top of the paving form free of concrete.
8.The wheels of finishing equipment operating on previously placed pavement shall be rubber faced. Track propelled equipment should be equipped with rubber protective pads on the crawler tracks, or the tracks shall travel on cushions of wood or belting. The near edge of wheels or tracks shall not be closer than 3 inches (75 mm) from edge of pavement. Provisions must also be made to prevent the screed from damaging the edge of the existing pavement surface.
9.a. Internal vibrating equipment shall be used ahead of the finishing machine.
b.Vibrators shall not contac t the side forms, dowel bars or reinforcing steel, nor transmit vibration to finishing machines or spreaders.
c.Vibrators shall consolidat e the full depth and width of the concrete in a single pass so that a uniform density is achieved without mix segregation or creation of excessive surface mortar. The vibrators shall be operated only when the machine to which they are attached is moving. The vibrators shall be placed to minimize overlap vibration.
d.The Contractor shall always have a tachometer available to monitor vibrator frequency. The vibrator frequency shall be within the manufacturer's specifications not to exceed 9,000 vpm.
10.a. The Contractor shall use a 10 foot (3 m) straightedge to continuously check the concrete surf ace smoothness. The allowable surface tolerance is 1/8 inch (3 mm).
b.The Contractor shall use a st raight steel channel [10 feet (3 m) long by 6 inches (150 mm) deep] to check the alignment of the straightedge.
c.Sufficient straightedges shall be available to maintain continuous paving operations.
11.Equipment required to install pavement joints is as follows: a. Air compressors shall be portable and able to maintain a nozzle air pressure of 90 psi (620 kPa) or greater. Suitable traps shall maintain the compressed air free of oil and moisture.
b.Sandblasting equipment shall be of proper size and capacity to obtain the cleaning specified and shall op erate at an air pressure of at least 90 psi (620 kPa). Nozzles shall be sized to the width of each joint. General Requirements 601.02 - 395 - c. Motor driven wire brushes shall have a stiff wire brush wheel able to clean the full depth of the jo int face openings at not less than 1000 rpm. The motor and brush shall be mounted on a frame with wheels and handles to move the unit along the joints to be cleaned. Brush rotation shall move debris away from the operator.
d.Joint saws
1.The saw shall be equipped with an adjustable guide.
2.The joint cut shall be made with a diamond-toothed blade. (3) The blade shall be water-cooled. (4) Two joint saws shall always be maintained on the project. (5) In an emergency, dry sawing is allowed with the Engineer's approval.
e.Early-cut system joint saws. (1) The early-cut system saw may use an abrasive type cutting blade.
2.The early-cut saw blade may be air cooled.
f.The hot-poured joint compound heater shall mechanically agitate the compound. A flame will not be allowed to contact the container surface. The melting unit shall h eat the material according to the manufacturer’s specifications to a pour ing consistency without damaging the joint compound.
g.A pressure type joint filling machine with a mixing unit shall be used. Hand caulking guns may be used in places that are inaccessible to the pressure equipment. - 396 - SECTION 602 -- PORTLAND CE MENT CONCRETE PAVEMENT SMOOTHNESS
602.01 General
1.This Specification establishes a standard for Portland cement concrete pavement smoothness, a nd defines defective pavement smoothness. The intent of the specification is to produce a finished Portland cement concrete pavement driving su rface with an International Roughness Index (IRI) no greater than 99 inches per mile.
2.Pavement smoothness will be evaluated as described in this section when the pay item “Portland Cement Concrete Smoothness Testing” is included in the contract.
3.When the pay item “Portland Cement Concrete Pavement Smoothness” is not included in the cont ract, the Contractor shall test the hardened concrete for surface irregularities with a non-contact inertial pavement profiler, a 10 foot (3 m) stra ightedge, or an approved device at the Engineers discretion. Areas showing high spots in excess of 1/8 inch (3 mm) in the 10 foot (3 m) span will be plainly marked and ground to the required profile.
602.02 Equipment
1.The Contractor shall furnish a non-contact inertial pavement profiler (profiler) that meets the requirement s of ASTM Standard E 950, certified by the manufacturer. The profiler shall be certified by the Department that it meets the ASTM Standard E 950 requirements.
2.The profiler may be a lightweight version or a high speed version.
3.The profiler shall be equipped wi th a computerized system that will record, analyze, and print the test data. The profiler shall be equipped with a guide bar and a large footprint height sensor specifically designed for surface profile measurements on te xtured Portland cement concrete surfaces.
4.The profiler shall produce a printed pavement profile summary report. The report shall include the following information.
a.Project number b. Test date c. Traffic lane d. Test direction e. Test path
f.Pass number (1 for initial test; 2, 3, etc. for repeat runs)
g.Operator’s name h. Project stations i. Data filter values j. IRI values fo r each test section
k.California profilograph emulat ion traces (profilograms) for each test section
l.Bump and dip locations for each test section, as determined by California profilograph emulation
Source: Nebraska Standard Specifications for Highway Construction, 2017 Edition. Pages 427–429 of 1,048.