HOT MIX ASPHALT - PLANT METHODS AND EQUIPMENT
320-1 General.
This Section specifies the basic equipment and operational requirements for hot mix asphalt (including warm mix asphalt) production facilities used in the construction of asphalt pavements and bases. Establish and maintain a quality control system that provides assurance that all materials and products submitted for acceptance meet Contract requirements.
320-2 Quality Control (QC) Requirements.
320-2.1 Minimum Producer QC Requirements: Perform as a minimum the following
activities:
1.Stockpiles:
a.Assure materials are placed in the correct stockpile;
b.Assure good stockpiling techniques;
c.Inspect stockpiles for separation, contamination, segregation, and other similar items ;
d.Properly identify and label each stockpile.
2.Incoming Aggregate:
a.Obtain gradations and bulk specific gravity (G sb) values from aggregate supplier for reference ;
b.Determine the gradation of all component materials and routinely compare gradations and G sb values to mix design.
3.Cold Bins:
a.Calibrate the cold gate/feeder belt for each material;
b.Determine cold gate/feeder belt settings;
c.Observe operation of cold feeder for uniformity ;
d.Verify accuracy of all settings ;
e.Verify that the correct components are being used, an d that all modifiers or additives or both are being incorporated into the mix .
4.Batch Plants :
a.Determine percent used and weight to be pulled from each bin to assure compliance with the mix design;
b.Check mixing time ;
c.Check operations o f weigh bucket and scales.
5.Drum Mixer Plants :
a.Determine aggregate moisture content ;
b.Calibrate the weigh bridge on the charging conveyor.
6.Control Charts: Maintain QC data and charts (updated daily ) for all QC Sampling and Testing and make available upon demand . Provide the following charts:
a.All components used to determine the composite pay factor (No. 8 sieve, No. 200 sieve, asphalt binder content, air voids, and density);
b.Gradation of incoming ag gregate;
c.Gradation, asphalt binder content and maximum specific gravity (G mm) of RAP; FY 2023-24 Return to Table of Contents
d.Any other test result or material characteristic (as determined by the Contractor) necessary for process control. The above listed minimum activities are to be considered normal activities necessary to control the production of hot mix asphalt at an acceptable quality level. Depending on the type of process or materials, some of the activities listed may not be necessary and in other cases, additional activit ies may be required. The frequency of these activities will also vary with the process and the materials. When the process varies from the defined process average and variability targets, the frequency of these activities will be increased until the proper conditions have been restored.
320-2.2 Minimum Process Control Testing Requirements: Perform, as a minimum,
the following activities at the testing frequencies provided in Table 320-1. QC tests used in the acceptance decision may be used to fulfill th ese requirement s. Table 320-1 Asphalt Plant - Materials Testing Frequencies Material Property Minimum Testing F requency Aggregate Gradation Once per 1,000 tons of incoming aggregate Asphalt Mix Asphalt Binder Content If daily production > 100 tons, once per day; If daily production > 1,000 tons, twice per day. * Asphalt Mix Bulk Specific Gravity (G mb) If daily production > 100 tons, once per day; If daily production > 1,000 tons, twice per day. * Asphalt Mix Gradation If daily production > 100 tons, once per day; If daily production > 1,000 tons, twice per day. * Asphalt Mix Maximum Specific Gravity (G mm) If daily production > 100 tons, once per day; If daily production > 1,000 tons, twice per day. * Asphalt Mix Temperature Each of first 5 loads, then once every 5 loads thereafter , per day per mix design. RAP Asphalt Binder Content Once per 1, 000 tons RAP RAP Gradation Once per 1,000 tons RAP RAP Maximum Specific Gravity (G mm) Once per 5,000 tons RAP *If less than 100 tons of mix is prod uced on each of successive days of production, resulting in a cumulative quantity of greater than 100 tons, then perform the indicated test.
320-2.3 Personnel Qualifications: Provide QC Technicians in accordance with
Section 105.
320-2.4 Hot Mix Asphalt Testing Laboratory Requirements: Furnish a fully equipped
asphalt laboratory at the production site. The laboratory must be qualified under the Department’s Laboratory Qualification Prog ram, as described in Section 105. In addition, the laboratory shall meet the following requirements: FY 2023-24 Return to Table of Contents
1.Area - The effective working area of the laboratory shall be a minimum of 180 square feet , with a layout of which will facilitate multiple tests being run simultaneously by two technicians. This area does not include the space for desks, chairs and file cabinets. Any variations shall be approved by the Engineer.
2.Lighting - The lighting in the lab must be adequate to illuminate all areas of the work.
3.Temperature Control - Equip the lab with heating and air conditioning units that provide a satisfactory working environment.
4.Ventilation - Equip the lab with exhaust fans that will remove all hazardous fumes from within the laboratory in accord ance with OSHA requirements.
5.Equipment and Supplies - Furnish the lab with the necessary sampling and testing equipment and supplies for performing contractor QC and Department Verification Sampling and Testing. A detailed list of equipment and suppli es required for each test is included in the appropriate FDOT, AASHTO, or ASTM Test Method. In the event testing equipment goes out of service during production, the Contractor may elect to use replacement equipment at another laboratory qualified, as described in Section 105, for up to 72 hours upon notification of the Engineer .
6.Personal Computer - Provide a personal computer capable of running a Microsoft ExcelTM spreadsheet program, along with a printer.
7.Communication - Provide a telephone an d fax machine (with a private line) for the use of the testing facility’s QC personnel. In addition, provide an internet connection capable of uploading data to the Department’s database and for e -mail communications.
320-3 Requirements for All Plants.
320-3.1 General: Design, manufacture, coordinate, and operate the asphalt plant in a
manner that will consistently produce a mixture within the required tolerances and temperatures specified.
320-3.2 Asphalt Plant Ticketing Systems: Use either a paper ticketing system or an
electronic ticketing (E -Ticketing) system.
320-3.2 1 Electronic Weigh Systems for Paper Ticketing: Equip the asphalt
plant with an electronic weigh system that has an automatic printout, is certified every six months by an approved certified scale technician, and meets monthly comparison checks with certified truck scales as specified in 320 -3.2.1.4. Weigh all plant produced hot mix asphalt on the electronic weigh system, regardless of the method of measurement for payment. Include, as a minimum, the following information on the printed delivery ticket:
1.Sequential load number
2.Project number
3.Date
4.Name and location of plant
5.Mix design number
6.Place for hand -recording mix temperature
7.Truck number
8.Gross, tare, and net tonnage per truck (as applicable)
9.Daily total tonnage of mix for the mix design Print the delivery ticket with an original and at least one copy. Furnish the original to the Engineer at the plant and one copy to th e Engineer at the paving site. Utilize any one of the following three electronic weigh systems. FY 2023-24 Return to Table of Contents
320-3.2 1.1 Electronic Weigh System on the Truck Scales: Provide an
electronic weigh system on all truck scales, which is equipped with an automatic record ation system that is approved by the Engineer. Use scales of the type that directly indicate the total weight of the loaded truck. Use scales meeting the requirements for accuracy, condition, etc., of the Bureau of Weights and Measures of the Florida Depar tment of Agriculture, and re -certify such fact every six months, either by the Bureau of Weights and Measures or by a registered scale technician.
320-3.2 1.2 Electronic Weigh System on Hoppers Beneath a Surge or
Storage Bin: Provide an electronic weigh system on the hopper (hopper scales or load cells) beneath the surge or storage bin, which is equipped with an automatic recordation system approved by the Engineer.
320-3.2 1.3 Automatic Batch Plants with Printout: For batch plants,
provide an approve d automatic printer system which will print the individual or cumulative weights of aggregate and liquid asphalt delivered to the pugmill and the total net weight of the asphalt mix measured by hopper scales or load cell type scales. Use the automatic prin ter system only in conjunction with automatic batching and mixing control systems that have been approved by the Engineer.
320-3.2 1.4 Monthly Electronic Weigh System Comparison Checks:
Check the accuracy of the electronic weighing system at the commenc ement of production and thereafter by one of the following two methods and maintain a record of the weights in the Scale Check Worksheet . The time period between scale checks shall not exceed 35 calendar days.
320-3.2 1.4.1 Electronic Weigh System on T ruck Scales:
1.The Engineer will randomly select a loaded truck of asphalt mix, a loaded aggregate haul truck, or another vehicle type approved by the Engineer and record the truck number and gross weight from the Contractor’s delivery ticket.
2.Weigh the selected truck on a certified truck scale, which is not owned by the Contractor and record the gross weight for the comparison check. If another certified truck scale is not available, the Engineer may permit another set of certified truck scal es owned by the Contractor to be used. The Engineer may elect to witness the scale check.
3.The gross weight of the loaded truck as shown on the Contractor’s delivery ticket will be compared to the gross weight of the loaded truck from the other cert ified truck scale. The maximum permissible deviation is 8 pounds per ton of load, based on the certified truck scale weight.
4.If the distance from the asphalt plant to the nearest certified truck scale is enough for fuel consumption to affect the ac curacy of the comparison checks, a fuel adjustment may be calculated by using the truck odometer readings for the distance measurement, and 6.1 miles per gallon for the fuel consumption rate, and 115 ounces per gallon for fuel weight.
5.During produc tion, when an additional certified truck scale is not available for comparison checks, the Engineer may permit the Contractor to weigh the truck on his certified scales used during production and then weigh it on another certified truck scale, as soon the other scale is available for the comparison checks. In addition to the periodic checks as specified above, check the scales at any time the accuracy of the scales becomes questionable. When such inaccuracy does not appear to be sufficient to seriously affect the weighing operations, the Engineer will allow a period of two calendar days for the Contractor to conduct the required scale check. FY 2023-24 Return to Table of Contents However, in the event the indicated inaccuracy is sufficient to seriously affect the mixture, the Engineer may re quire immediate shut -down until the accuracy of the scales has been checked and necessary corrections have been made. Include the cost of all scale checks in the bid price for asphalt concrete, at no additional cost to the Department.
320-3.2 1.4.2 Ele ctronic Weigh System on Hoppers Beneath a
Surge or Storage Bin and Automatic Batch Plants with Printout:
1.The Engineer will randomly select a loaded truck of asphalt mix and record the truck number, and the net weight of the asphalt mix from the Contractor’s delivery ticket.
2.Weigh the selected truck on a certified truck scale, which is not owned by the Contractor and record the gross weight for the comparison check. If another certified truck scale is not available, the Engineer may permit an other set of certified truck scales owned by the Contractor to be used. The Engineer may elect to witness the scale check.
3.Deliver the asphalt mix to the project, then weigh the selected empty truck on the same certified truck scales. Record the ta re weight of the truck.
4.Compare the net weight of the asphalt mix from the delivery ticket to the calculated net weight of the asphalt mix as determined by the certified truck scale weights. The maximum permissible deviation is 8 pounds per ton of load, based on the certified truck scale weight.
5.Use the fuel adjustment as specified in 320 -3.2.4.1(4), when the distance from the asphalt plant to the nearest certified truck scale is enough for fuel consumption to affect the accuracy of the comp arison checks.
6.During production, when an additional certified truck scale is not available for comparison checks, the Engineer may permit the Contractor to load a truck with aggregate from the pugmill, surge or storage bin, and follow the above pr ocedures to conduct the comparison checks as soon as certified truck scale is available. If the check shows a greater difference than the tolerance specified above, then recheck on a second set of certified scales. If the check and recheck indicate th at the printed weight is out of tolerance, have a certified scale technician check the electronic weigh system and certify the accuracy of the printer. While the system is out of tolerance and before its adjustment, the Engineer may allow the Contractor to continue production only if provisions are made to use a set of certified truck scales to determine the truck weights.
320-3.2 2 Electronic Weigh Systems for E -Ticketing: Equip the asphalt plant
with an electronic weigh system that has an automatic prin tout, is certified every six months by an approved certified scale technician, and meets monthly comparison checks with certified truck scales as specified in 320 -3.2.2.3. Weigh all plant produced hot mix asphalt on the electronic weigh system, regardless of the method of measurement for payment. Include, as a minimum, the following information in the electronic delivery ticket:
1.Sequential load number
2.Project’s Financial Identification Number (FIN)
3.Date
4.Name and location of plant
5.Mix design number
6.Separate, individual, data entry locations for recording mix temperature by: FY 2023-24 Return to Table of Contents
a.Plant QC
b.Plant VT
c.Roadway QC
d.Roadway VT
7.Truck number
8.Gross, tare, and net tonnage per truck
9.Daily cu mulative tonnage of mix for the mix design
320-3.2 2.1 Electronic Ticketing ( E-Ticketing) System: Provide an e -
Ticketing System (including any necessary software and hardware ) capable of monitoring, collecting, storing, and reporting the information req uired by the Contract for all loads of asphalt mix delivered to the project. After each truck is loaded, electronically record and use a web service to upload the ticket information to the E-ticketing software database. The E-ticketing system shall provide each truck load’s ticket information to users of the e -ticketing software. E-ticketing software must provide the Engineer the ability to access real- time monitoring of asphalt truck load ticket information as described herein . The e-Ticketing system shall be integrated with the Load Read -Out scale system at the asphalt plant site. The e-ticketing system shall have offline capabilities to prevent data loss in the event of power loss or loss of connectivity.
320-3.2 2.1.1 E-Ticketing System Co nstruction Requirements:
Install and operate equipment in accordance with the manufacturer’s specifications.
320-3.2 2.1.2 Data Deliverables: Provide to the Engineer a means
of gathering report summaries by way of iOS or Android apps, web pages, or an y other method at the disposal of the Engineer. The Engineer may request data at any time during paving operations. In addition to providing reports referenced in this specification, provide monthly reports, as well as, a final, end of project report in th e e-ticketing software and in a comma separated value (.csv) file. Provide all e -ticketing database data required in this Section in the monthly and end of project reports and .csv files.
320-3.2 2.1.3 Real-Time Continuous e-Ticketing Data Items:
Provide the Engineer access to the e-Ticketing system data viewer which displays the following information in real -time with a web -based or App-based system compatible with iOS , Windows, or Android environments:
1.Each Truck:
a.Unique Truck ID
b.Sequential Truck Load Number
c.Mix Design Number
d.Net Weight of material being transported (to the nearest 0.01 ton)
e.Running Daily Total of Net Weight of material being transported (to the nearest 0.01 ton)
f.Project’s Financial Identification Number
2.Project Location
320-3.2 2.1.4 Daily Summary : Provide the following summary
information to the Engineer electronically within 4 hours of beginning operations on the next working day :
1.List of Individual Loads FY 2023-24 Return to Table of Contents
a.Contractor Name
b.Project’s Financial Identification Number (FIN)
c.Unique Truck ID
d.Sequential Load Number
e.Net Weight for Payment (nearest 0.01 tons)
f.Net Weight of Waste (nearest 0.01 tons)
g.Date Paved
h.Mix Temperature Measurement s (Plant QC, Plant VT, Roadway QC, and Roadway VT)
i.Time Loaded at Plant site
320-3.2 2.2 Electronic Weigh Systems: Utilize any one of the following
three electronic weigh systems.
320-3.2 2.2.1 Electronic Weigh System on the Truck Scales:
Provide an electronic weigh system on all truck scales, which is equipped with an automatic recordation system that is approved by the Engineer. Use scales of the type that directly indicate the total weight of the loaded truck. Use scales meeting the requirements for accuracy, condition, etc., of the Bureau of Weights and Measures of the Florida Department of Agriculture, and re - certify such fact every six months, either by the Bureau of Weights an d Measures or by a registered scale technician.
320-3.2 2.2.2 Electronic Weigh System on Hoppers Beneath a
Surge or Storage Bin: Provide an electronic weigh system on the hopper (hopper scales or load cells) beneath the surge or storage bin, which is e quipped with an automatic recordation system approved by the Engineer.
320-3.2 2.2.3 Automatic Batch Plants: For batch plants, provide
an electronic weigh system, which is equipped with an automatic recordation system, that is approved by the Engineer, which will directly indicate the individual or cumulative weights of aggregate and liquid asphalt delivered to the pugmill and the total net weight of the asphalt mix measured by hopper scales or load cell type scales. Use the electronic systems only in conjunction with automatic batching and mixing control systems that have been approved by the Engineer.
320-3.2 2.3 Monthly Electronic Weigh System Comparison Checks:
Check the accuracy of the electronic weighing system at the commencement of production and thereafter by one of the following three methods and maintain a record of the weights in the Scale Check Worksheet. The time period between scale checks shall not exceed 35 calendar days.
320-3.2 2.3.1 Electronic Weigh System on Truck Scales:
1.The Engineer will randomly select a loaded truck of asphalt mix, a loaded aggregate haul truck, or another vehicle type approved by the Engineer and record the truck number and gross weight from the Contractor’s delivery ticket.
2.Weigh the selected truck on a certified truck scale, which is not owned by the Contractor and record the gross weight for the comparison check. If another certified truck scale is not available, the Engineer may permit another set of certified truck scales owned by the Cont ractor to be used. The Engineer may elect to witness the scale check.
3.The gross weight of the loaded truck as shown on the Contractor’s delivery ticket will be compared to the gross weight of the loaded truck from the FY 2023-24 Return to Table of Contents other certified truck scale. Th e maximum permissible deviation is 8 pounds per ton of load, based on the certified truck scale weight.
4.If the distance from the asphalt plant to the nearest certified truck scale is enough for fuel consumption to affect the accuracy of the comparis on checks, a fuel adjustment may be calculated by using the truck odometer readings for the distance measurement, and 6.1 miles per gallon for the fuel consumption rate, and 115 ounces per gallon for fuel weight.
5.During production, when an additiona l certified truck scale is not available for comparison checks, the Engineer may permit the Contractor to weigh the truck on his certified scales used during production and then weigh it on another certified truck scale, as soon as the other scale is avail able for the comparison checks. In addition to the periodic checks as specified above, check the scales at any time the accuracy of the scales becomes questionable. When such inaccuracy does not appear to be sufficient to seriously affect the weighing operations, the Engineer will allow a period of two calendar days for the Contractor to conduct the required scale check. However, in the event the indicated inaccuracy is sufficient to seriously affect the mixture, the Engineer may require immediate shut -down until the accuracy of the scales has been checked and necessary corrections have been made. Include the cost of all scale checks in the bid price for asphalt concrete, at no additional cost to the Department.
320-3.2 2.3.2 Electronic Weigh System on Hoppers Beneath a
Surge or Storage Bin:
1.The Engineer will randomly select a loaded truck of asphalt mix and record the truck number, and the net weight of the asphalt mix from the Contractor’s delivery ticket.
2.Weigh the selected truck on a certified truck scale, which is not owned by the Contractor and record the gross weight for the comparison check. If another certified truck scale is not available, the Engineer may permit another set of certified truck scales owned by the Contractor to b e used. The Engineer may elect to witness the scale check.
3.Deliver the asphalt mix to the project, then weigh the selected empty truck on the same certified truck scales. Record the tare weight of the truck.
4.Compare the net weight of the asph alt mix from the delivery ticket to the calculated net weight of the asphalt mix as determined by the certified truck scale weights. The maximum permissible deviation is 8 pounds per ton of load, based on the certified truck scale weight.
5.Use the fuel adjustment as specified in 320 -3.2.2.3.1(4), when the distance from the asphalt plant to the nearest certified truck scale is enough for fuel consumption to affect the accuracy of the comparison checks.
6.During production, when an additional cer tified truck scale is not available for comparison checks, the Engineer may permit the Contractor to load a truck with aggregate from the pugmill, surge or storage bin, and follow the above procedures to conduct the comparison checks as soon as certified t ruck scale is available. If the check shows a greater difference than the tolerance specified above, then recheck on a second set of certified scales. If the check and recheck indicate that the printed weight is out of tolerance, have a certified scale technician check the electronic weigh system and certify the accuracy of the printer. While the system is out of tolerance and before its FY 2023-24 Return to Table of Contents adjustment, the Engineer may allow the Contractor to continue production only if provisions are made to use a set of certified truck scales to determine the truck weights.
320-3.2 2.3.3 Electronic Weigh System on Hoppers Beneath a
Surge or Storage Bin and Automatic Batch Plants with Printout:
1.The Engineer will randomly select a loaded truck of asphalt mix and record the truck number, and the net weight of the asphalt mix from the Contractor’s delivery ticket.
2.Weigh the selected truck on a certified truck scale, which is not owned by the Contractor and record the gross weight for the comparison check. If another certified truck scale is not available, the Engineer may permit another set of certified truck scales owned by the Contractor to be used. The Engineer may elect to witness the scale check.
3.Deliver the asphalt mix to the project, then weigh t he selected empty truck on the same certified truck scales. Record the tare weight of the truck.
4.Compare the net weight of the asphalt mix from the delivery ticket to the calculated net weight of the asphalt mix as determined by the certified truck scale weights. The maximum permissible deviation is 8 pounds per ton of load, based on the certified truck scale weight.
5.Use the fuel adjustment as specified in 320 -3.2.1.4.1(4), when the distance from the asphalt plant to the nearest certified truc k scale is enough for fuel consumption to affect the accuracy of the comparison checks.
6.During production, when an additional certified truck scale is not available for comparison checks, the Engineer may permit the Contractor to load a truck with aggregate from the pugmill, surge or storage bin, and follow the above procedures to conduct the comparison checks as soon as certified truck scale is available. If the check shows a greater difference than the tolerance specified above, then recheck on a second set of certified scales. If the check and recheck indicate that the weight on the E -Ticket is out of tolerance, have a certified scale technician check the electronic weigh system and certify the accuracy of the E -Ticketing system. While the syst em is out of tolerance and before its adjustment, the Engineer may allow the Contractor to continue production only if provisions are made to use a set of certified truck scales to determine the truck weights.
320-3.3 Asphalt Binder: Meet the following re quirements:
320-3.3 1 Transportation: Deliver the asphalt binder to the asphalt plant at a
temperature not to exceed 370°F, and equip the transport tanks with sampling and temperature sensing devices meeting the requirements of 300-3.2.
320-3.3 2 Stora ge: Equip asphalt binder storage tanks to heat the liquid asphalt
binder to the temperatures required for the various mixtures. Heat the material in such a manner that no flame comes in contact with the binder. Heat or insulate all pipe lines and fittings. Use a circulating system of adequate size to ensure proper and continuous circulation during the entire operating period. Locate a thermometer, reading from 200 to 400°F, either in the storage tank or in the asphalt binder feed line. Maintain the asphalt binder in storage within a range of 230 to 355°F in advance of mixing operations. Locate a sampling device on the discharge piping exiting the storage tank or at a location as approved by the Engineer. Provide a metal can of one quart capacity for binder sampling at the request of the Engineer.
320-3.4 Aggregate : Meet the following requirements:
FY 2023-24 Return to Table of Contents
320-3.4 1 Stockpiles: Place each aggregate component in an individual stockpile,
and separate each from the adjacent stockpiles, either by space or by a system of bulkheads. Prevent the intermingling of different materials in stockpiles at all times. Identify each stockpile, including RAP, as shown on the mix design. Form and maintain stockpiles in a manner that will prevent segregation. If a stockpile is determined to be segregated, discontinue the use of the material on the project until the appropriate actions have been taken to correct the problem.
320-3.4 2 Blending of Aggregates: Stockpile all aggregates prior to blending or
placing in the cold f eed bins. If mineral filler or hydrated lime is required in the mix, feed or weigh it in separately from the other aggregates.
320-3.4 2.1 Cold Feed Bin: Provide a separate cold feed bin for each
component of the fine and coarse aggregate required by th e mix design . Equip the cold feed bins with accurate mechanical means for feeding the aggregate uniformly into the dryer in the proportions required for the finished mix to maintain uniform production and temperature. When using RAP as a component material , prevent any oversized RAP from being incorporated into the completed mixture by the use of: a grizzly or grid over the RAP bin ; in-line roller or impact crusher; screen; or other suitable means . If oversized RAP material appears in the completed recycled mix, take the appropriate corrective action immediately. If the appropriate corrective actions are not immediately taken, stop plant operations. Use separate bin compartments in the cold aggregate feeder that are constructed to prevent any spilling or leakage of aggregate from one cold feed bin to another. Ensure that each cold feed bin compartment has the capacity and design to permit a uniform flow of aggregates. Mount all cold feed bin compartments over a feeder of uniform speed, which will deliver the specified proportions of the separate aggregates to the drier at all times. If necessary, equip the cold feed bins with vibrators to ensure a uniform flow of the aggregates at all times.
320-3.4 2.2 Gates and Feeder Belts: Provide each cold feed bin
compartment with a gate and feeder belt, both of which are adjustable to assure the aggregate is proportioned to meet the requirements of the mix design.
320-3.4 3 Screening Unit : Remove any oversized pieces of aggregate by the use
of a scalping screen. Do not return this oversized material to the stockpile for reuse unless it has been crushed and reprocessed into sizes that will pass the scalping screen. Ensure that the quantity of aggregates being discharged onto the screens does not exceed the capacity of the screens to actually separate the aggregates into the required sizes.
320-3.5 Dryer: Provide a dryer of satisfactory design for heating and drying the
aggregate. Use a dryer capable of heating the aggregate to within the specifi ed temperature range for any mix, and equip the dryer with an electric pyrometer placed at the discharge chute to automatically register the temperature of the heated aggregates.
320-3.6 Asphalt Binder Control Unit: Provide a satisfactory means, either by weighing,
metering, or volumetric measuring, to obtain the proper amount of asphalt binder material in the mix, within the tolerance specified for the mix design.
320-3.7 Contractor’s Responsibilities: Acceptance of any automatic delivery ticket
printout, electronic weight delivery ticket, other evidence of weight of the materials or approval of any particular type of material or production method will not constitute agreement by the Department that such matters are in accordance with the Contract Documen ts and it shall be the Contractor’s responsibility to ensure that the materials delivered to the project are in accordance with the Contract Documents. FY 2023-24 Return to Table of Contents
320-4 Additional Requirements for Batch Plants.
320-4.1 Heating and Drying: Heat and dry the aggregate before screening. Control t he
temperature of the aggregate so the temperature of the completed mixture at the plant falls within the permissible range allowed by this Section.
320-4.2 Gradation Unit: Provide plant screens capable of separating the fine and coarse
aggregates and of further separating the coarse aggregate into specific sizes. In addition, equip the gradation unit with a scalping screen to restrict the maximum size of the aggregates. In the event that the plant is equipped with cold feed bins that are capable of adequately controlling the gradation of the mixture, the use of plant screens is optional.
320-4.3 Hot Bins: Provide storage bins of sufficient capacity to supply the mixer when it
is operating at full capacity. Provide hot bins with divided compartments to ensure separate and adequate storage of the appropriate fractions of the aggregate. Equip each compartment with an overflow chute of suitable size and location to prevent any b acking up of material into other bins.
320-4.4 Weigh Box or Hopper: Equip the batch plant with a means for accurately
weighing each bin size of aggregate and the mineral filler into the weigh box or hopper.
320-4.5 Pugmills: Utilize a pugmill capable of mixing the aggregate and the asphalt
binder.
320-5 Additional Requirements for Drum Mixer Plants.
320-5.1 Weight Measurements of Aggregate: Equip the plant with a weigh -in-motion
scale capable of measuring the quantity of aggregate (and RAP) entering the dryer.
320-5.2 Synchronization of Aggregate Feed and Asphalt Binder Feed: Couple the
asphalt binder feed control with the total aggregate weight device, including the RAP feed, in such a manner as to automatically vary the asphalt binder feed rate as necessary to maintain the required proportions.
320-5.3 Hot Storage or Surge Bins: Equip the plant with either a surge bin or storage
silo that is capable of storing an adequate amount of material to assure a uniform and consistent product.
320-6 Preparation of the Mixture.
320-6.1 Mixing: After the aggregate is dried and properly proportioned, mix the
aggregate, along with any other components, with the asphalt binder to produce a thoroughly and uniformly coated mixture. Do not produce the mix b y altering the component blend percentage of the RAP or sand by more than plus or minus 5.0% from the job mix formula on the approved mix design. For mix designs using fractionated RAP, the combined blend change for all RAP components must not exceed plus or minus 5.0%. The plus or minus 5.0% maximum component change does not apply to crushed virgin aggregate components during production.
320-6.2 Storage: If necessary, store the asphalt mixture in a surge bin or hot storage silo
for a maximum of 72 hours. For FC-5 mixtures containing mineral fibers , store the asphalt mixture in a surge bin or hot storage silo for a maximum of one hour. For FC-5 mixtures containing cellulose fibers, store the asphalt mixture in a surge bin or hot storage silo for a maximum o f 1-1/2 hours.
320-6.3 Mix Temperature: Produce the mixture with a temperature within the master
range as defined in Table 320-2.
320-6.3 1 Test Requirements: Determine the temperature of the completed
mixture using a quick -reading thermometer through a hole in the side of the loaded truck immediately after loading. Locate a 1/4 inch hole on both sides of the truck body within the FY 2023-24 Return to Table of Contents middle third of the length of t he body, and at a distance from 6 to 10 inches above the surface supporting the mixture. If a truck body already has a hole located in the general vicinity of the specified location, use this hole. At the Engineer’s discretion, the Contractor may take the temperature of the load over the top of the truck in lieu of using the hole in the side of the truck.
320-6.3 2 Test Frequency: The normal frequency for taking asphalt mix
temperatures will be for each day, for each design mix on the first five loads and one out of every five loads thereafter. Take the temperature of the asphalt mix at the plant and at the roadway before the mix is placed at the normal frequency. Record the temperature on the front of the respective delivery ticket. The Engineer shall rev iew the plant and roadway temperature readings and may take additional temperature measurements at any time. If any single load at the plant or at the roadway is within the master range shown in Table 320-2 but does not meet the criteria shown in Table 320-3, the temperature of every load will be monitored until the temperature falls within the specified tolerance range in Table 320-3; at this time the normal frequency may be resumed. For warm mix asphalt, the Contractor may produce the first five loads of the production day and at other times when approved by the Engineer, at a hot mix asphalt temperature not to exceed 330°F for purposes of heating the asphalt paver. For this situation, the upper tolerances of Tables 320-2 and 320 -3 as applied to the war m mix asphalt mix design do not apply. For windrow paving, in addition to the truck load temperature measurements noted above, perform windrow temperature measurements at a frequency of one measurement per 500 feet of windrow placed. Check the temperatu re of the windrow asphalt mixture using a quick -reading thermometer or directly in front of the windrow material transfer vehicle, but not so close that paving must be stopped . Measure the temperature of the windrow beneath the exposed surface by shoveling away a portion of the windrow and then measuring the temperature. For windrow temperature measurements, the requirements of Table 320 -2 and
320-3 apply.
320-6.3 3 Rejection Criteria: Reject any load or portion of a load of asphalt mix at the
plant or at the roadway with a temperature outside of its respective master range shown in Table 320-2. Notify the Engineer of the rejection immediately. The maximum temperature for any load of mixture containing PG 76 -22 PMA or High Polymer binder shall not exceed 35 5°F. Table 320-2 Mix Temperature Master Range Tolerance Location Acceptable Temperature Tolerance Plant Mixing Temperature ±30 °F* Roadway (mix in truck) Compaction Temperature ±30°F* Roadway (mix in windrow) Compaction Temperature +30°F*, -40°F *Not to exceed 355°F for mixtures containing PG 76 -22 PMA or High Polymer binder. Table 320-3 Mix Temperature Tolerance from Verified Mix Design Any Single Measurement ±25°F
320-7 Transportation of the Mixture.
Transport the mix in trucks of tight construction, which prevents the loss of material and the excessive loss of heat and previously cleaned of all foreign material. After cleaning, thinly FY 2023-24 Return to Table of Contents coat the inside surface of the truck bodies with soapy water or an asphalt release agent as needed to prevent the mixture from adhering to the beds. Do not allow excess liquid to pond in the truck body. Do not use a release agent that will contaminate, degrade, or alter the characteristics of the asphalt mix or is hazardo us or detrimental to the environment . Petroleum derivatives (such as diesel fuel) , solvents, and any product that dissolves asphalt are prohibited . Provide each truck with a tarpaulin or other waterproof cover mounted in such a manner that it can cover the entire load when required. When in place, overlap the waterproof cover on all sides so that it can be tied down. Cover each load during cool and cloudy weather and at any time it appears rain is likely during transit with a tarpaulin or waterproof cover. Cover and tie down all loads of friction course mixtures. FY 2023-24 Return to Table of Contents SECTION 327 MILLING OF EXISTING ASPHALT PAVEMENT
327-1 Description.
Remove existing asphalt concrete pavement by milling to improve the rideability and cross slope of the finished pavement, to lower the finished grade adjacent to existing curb before resurfacing, or to completely remove existing pavement. When milling to improve rideability, the Plans will specify an average depth of cut. Take ownership of milled material.
327-2 Equipment.
Provide a milling machine capable of maintaining a depth of cut and cross slope to achieve the results specified in the Contract Documents. Use a machine with a minimum overall length (out -to-out measurement excluding the conveyor) of 18 feet and a minimum cutting width of 6 feet. Equip the milling machine with a built-in automatic grade control system that can control the transverse slope and the longitudinal profile to produce the specified results. To start the project, the Engineer will approve any commercially manufactured milling machine that meets the abov e requirements. If it becomes evident after starting milling that the milling machine cannot consistently produce the specified results, the Engineer will reject the milling machine for further use. The Contractor may use a smaller milling machine when mi lling to lower the grade adjacent to existing curb or other areas where it is impractical to use the above described equipment. Equip the milling machine with means to effectively limit the amount of dust escaping during the removal operation. For comple te pavement removal, the Engineer may approve the use of alternate removal and crushing equipment in stead of the equipment specified above.
327-3 Construction.
327-3.1 General: Remove the existing raised pavement markers (RPMs) before milling.
Include the cost of removing existing RPMs in the price for milling. When milling to improve rideability or cross slope, remove the existing pavement to the average depth specified in the Plans, in a manner that will restore the pavement surface to a uniform cross slope and longitudinal profile. The Engineer may require the use of a stringline to ensure maintaining the proper alignment. Establish the longitudinal profile of the milled surface in accordance with the milling plans. Ensure the final cross slope of th e milled surface parallels the surface cross slope shown in the Plans or as directed by the Engineer. Establish the cross slope of the milled surface by a second sensing device near the outside edge of the cut or by an automatic cross slope control mechani sm. The Plans may waive the requirement of automatic grade or cross slope controls where the situation warrants such action. Operate the milling machine to minimize the amount of dust being emitted. The Engineer may require prewetting of the pavement. FY 2023-24 Return to Table of Contents
Source: Florida Standard Specifications for Road and Bridge Construction, 2024 Edition. Pages 271–283 of 1,299.