118 SECTION 151
151.01 Pneumatic -Tired Rollers
A.General. Use rollers having at least seven wheels with pneumatic tires of equal size and ply. Arrange wheels to provide complete coverage of the area the roller travels. Do not use petroleum products to moisten the tires . Submit the data used to determine the contact pressures for the full range of the manufacturer’s recommended wheel loads and tire inflation pressures. Inflate tires so that all tires are within a single 5 psi range. Use rollers that can be loaded to a gross weight of at least 225 pounds per inch of compaction width. Provide the empty and ballasted weights using one of the following methods : − Weigh the roller if it has been modified from its original design or if the ballast weight is unknown; or − Use the manufacturer ’s weight ratings if the roller has not been modified and ballast weight is known.
B.Tow-Type Pneumatic-Tired Roller . Operate rollers with tire inflation pressures and wheel loads as specified by manufacturer.
C.Self-Propelled Pneumatic-Tired Roller. Equip rollers with: − positive and accurate steering control; − skirting large enough to retain heat on the tires; − smooth-tread tires; − close -fitting scrapers for each tire; and − a system for uniformly moistening each tire without excessive use of water and detergent. Start, stop, and reverse direction smoothly without jerking or backlash. Wobble wheel rollers are not allowed. Operate rollers with contact pressure between 40 and 90 psi. Contact pressure is the average ground pressure, expressed in psi, obtained when the wheel load in pounds is divided by the gross contact area in square inches of the tire. 119 151.02 Vibratory Sheepsfoot/Pad Foot/Extended Pad Foot Roller Use a vibratory sheepsfoot/pad foot/extended pad foot roller with: − the capability of developing centrifugal force of 50,000 pounds or more; − a minimum operating weight of 23,000 pounds; and − a minimum roller width of 6 feet.
151.03 Steel- Wheel Rollers
A.Smooth -Faced Steel-Wheel Roller.
1.General. Use self-propelled rollers equipped with: − smooth-faced steel -wheels free of defects that mar the surface; − positive and accurate steering control; − adjustable spring scrape rs for each wheel; and − a system for each wheel that uniformly moistens the full width without use of excess water. Do not use petroleum products to moisten the roller. Start, stop, and reverse direction smoothly without jerking or backlash. Provide the empty and ballasted weights as specified in Section 151.01 A.1, “General”.
2.Smooth -Faced Steel-Wheel Roller: Tandem – Type A. Use a two-axle or three- axle tandem with a fully ballasted gross weight of 10 tons or more.
3.Smooth -Faced Steel-Wheel Roller: Tandem – Type B. Use a two-axle or three- axle tandem with a fully ballasted gross weight of 8 tons or more.
B.Vibratory Roller. Use self-propelled drum -type rollers, capable of static or dynamic mode, equipped with: − spray bars; − automatic vi bratory shut off; − accurate and working frequency gauge for each drum or provide an accurate hand- held resonant reed tachometer for each roller ; − 135 pounds per linear inch (PLI) of static force; and − 300 PLI of total applied force. Repair damaged or malfunctioning frequency gauges and tachometers within 48 hours. Provide instructions on the procedures for making amplitude adjustments for each roller. Do not exceed 4 mph when traveling in static mode, prior to achieving required density. Use rollers on plant mix base and hot bituminous pavement as specified in Table 151 -01. Use rollers with adjustable amplitude and operate at low amplitude with a minimum of 10 impacts per linear foot. 120 Table 151-01 Impacts per Linear Foot Roller Speed MPH (ft/min) Vibrations per Minute (VPM) 1800 2000 2200 2400 2600 2800 3000 1.0 (88) 20.4 22.7 25.0 27.2 29.5 31.8 34.1 1.5 (132) 13.6 15.2 16.7 18.2 19.7 21.2 22.7 2.0 (176) 10.2 11.4 12.5 13.6 14.8 15.9 17.0 2.5 (220) - - 10.0 10.9 11.8 12.7 13.6 3.0 (264) - - - - - 10.9 11.4
151.04 Combination Roller
Use rollers as specified in Section 151.03 B, “Vibratory Roller”, except rollers shall have a single vibrating drum in the front and four smooth pneumatic tires in the rear, with a gross weight of 20 tons or more. Inflate tires so that all tires are within a single 5 psi range. Ensure tires have contact pressure as specified in Section 151.01 C , “Self -Propelled Pneumatic Tire Roller”. Section 152 121 SECTION 152 TRUCKS
152.01 Trucks
A.General. Use trucks that prevent contents from escaping during transit.
B.Water Trucks. Use water trucks that have the following features: − Capability of evenly distributing water; − Watertight connections and tanks; and − Control valves operated from the dri ver’s seat.
C.Aggregate Trucks. Use a truck with a dump box capable of controlled discharge.
D.Bituminous Trucks. Use trucks equipped with tarpaulins to protect the asphalt from weather. Install tarps free of holes larger than 0.5 inches in diameter and of sufficient size to completely cover the opening above the asphalt. Use a truck with a dump box capable of controlled discharge. Use a smooth-lined dump box, free from cracks, holes, and deep dents. Use trucks that are equipped with a hole of sufficient size for a thermometer, on the driver’s side in the middle of the box. Discharge material without the dump body or truck frame making direct contact or exerting pressure on the paver. Lubricate dump box when necessary with a thin film of material that does not dissolve the bitumen. Do not use petroleum distillates. Drain excess coating from dump box before use.
E.Bituminous Tank Trucks. Ensure bituminous tank trucks are sealed at the refinery. Equip tank trucks with a conveniently located bitumen-sampling valve. Ensure the valve is inside the tank and the valve stem and outlet extend outside the tank.
Source: North Dakota Standard Specifications for Road and Bridge Construction, 2022 Edition. Pages 153–155 of 550.