122 SECTION 153
153.01 Reclaimer
Use a self-propelled machine capable of pulverizing and mixing to a depth of 18 inches that also has the following features: − Capable of incorporating water into the mixture; − Produces a homogeneous mixture that has a uniform moisture content; and − Uses a control system that automatically controls the elevation of the cutting head.
153.02 Roadbed Planers
Use a track mounted roadbed planer equipped with rotary cutting mechanisms. Equip the planer with an automatic grade control that maintains the elevation at both sides of the planer by controlling the elevation of one side and the crown, or each side independently. Use an erected string line or other approved grade reference. Use a tightly stretched wire or string as the string line. Offset the string line parallel to the pavement edge on one or both sides and parallel to the established grade of the pavement surface. Section 154 123 SECTION 154 BITUMINOUS EQUIPMENT
154.01 Mixing Plants
A.General. Equip the mixing plant with individual bins, or a bin with individual compartments, for each aggregate component. Construct bins to prevent intermingling of aggregate. Provide uniform production that is uninterrupted under normal operating conditions. Use mixing plants capable of calibrating and checking the proportions of each material.
B.Storage and Heating Equipment. Use storage tanks that uniformly heat the bitumen to the required temperature without damage or changes to its characteristics. Do not use direct flames against the storage tanks. Equip the tanks with a ther mometer that registers the temperature of the bitumen. Provide measuring sticks and outage tables for calibration and determining quantity.
C.Feeders. Mechanically feed aggregates into the drier.
D.Driers. Use driers that continuously agitate, heat, and dry the aggregate.
E.Thermometric Equipment. Use thermometric equipment that automatically records mix temperature as the mix is discharged from the plant. Record and submit each day’s production on a chart. Use a graduated with time increments of 15 minutes and temperature increments 10°F. Record temperature variations of 20°F within one minute of the time the variation occurs. Place the equipment where it is unaffected by plant vibration. Place a transparent dust-proof cover over the equipment.
F.Flow Rate Meter . Measure and record the quantity of bitumen being discharged into the mixer with a flow rate meter with totalizer. Use a totalizer capable of recording up to 1,000,000 gallons with a certified accuracy within 0.20 percent. Use a flow rate meter and totalizer that automatically temperature-corrects to 60°F. Calibrate the flow meter before the start of the Project and as necessary. Provide the flow rate meter’s operations manual. Submit a chart, generated by the flow meter, showing the as phalt percentage of the total mix on a time-coordinated basis. Use a chart that has maximum increments of 0.10 percent of the total mix. Keep the display and recorder accessible to the Engineer. Correct the flow if it varies by more than 0.25 percentage p oints from the set percentage of asphalt. Adjust the plant to meet tolerance within 30 minutes after the first start-up of the day and 5 minutes after any additional start-up.
Source: North Dakota Standard Specifications for Road and Bridge Construction, 2022 Edition. Pages 157–157 of 550.