154 – CONCRETE PAVEMENT AND CO NCRETE STRUCTURE EQUIPMENT
150-10 The Engineer may accept transverse grooving equipmen t with a fluted float (instead of a metal comb)
provided the fluted float produces transverse grooves similar in dimension to the requirements of the metal comb. Small or irregular areas may be grooved by hand methods.
c.Longitudinal Grooving Equipment. Use standard manufacture, longitudinal grooving equipment capable of covering the width of the pavement in a single pass. Use longitudinal grooving equipment with a metal comb that is capable of producing a uniform pattern of longitudinal grooves approximately 3/16 inch wide, spaced at ¾ inch centers and ⅛ to ¼ inch deep. The Engineer may accept longitudinal grooving equipment with a fluted float (instead of a metal comb) provided the fluted float produces longitudinal grooves similar in dimension to the requirements of the metal comb. Small or irregular areas may be grooved by hand methods. 154.8 CONCRETE CURING CO MPOUND DISTRIBUTOR Use standard manufacture concrete curing compound distributors capable of continually mixing and uniformly spraying liquid membrane-forming compounds at the minimum rate of 1 gallon per 150 square feet of surface. Use concrete curing compound distributors capable of spraying both the surface a nd the edges of the slab at the same time. 154.9 CONCRETE SAWING EQUIPMENT Use standard manufacture concrete sawing equipment capable of making cuts to the specified dimensions. Use concrete saws with either water-cooled diamond-edge blades or abrasive wheel blades. Other sawing devices are based on acceptable perfor mance, and with the appr oval of the Engineer. Keep at least one stand-by saw and an adequate supply of blades on the project during the sawing operations. 155 – ASPHALT SURFACING AND ASPHALT RECYCLING EQUIPMENT
150-11 Section 155
ASPHALT SURFACING AND ASPHALT RECYCLING EQUIPMENT 155.1 EQUIPMENT FOR HEAT ING ASPHALT MATERIALS
a.Use equipment for heating asphalt materials at pr oject asphalt plant sites by one of the following methods: Circulate steam, hot gases or hot oil through coils of a tank. Circulate the asphalt material around a system of heated coils or pipes. Circulate the asphalt material through a system of coils or pipes enclosed in a heated jacket. Other approved means subject to the requirements of this specification. Construct the heating device to prevent direct flame from striking the surface of the coils, pipes or jacket through which the asphalt material is circulated. Operate the heating device in a manner that shall not damage or change the characteristics of the asphalt material.
b.Railroad tank cars or truck tankers that have defectiv e coils, or from which the coils have been removed, shall be rejected by the Engineer, un less the Contractor can provide satisf actory auxiliary means for heating the asphalt material without contamination and introducing mo isture. Do not use a tanker connection or any other equipment by means of which free steam can be introduced directly into th e asphalt material as a means of agitation or auxiliary heating. 155.2 ASPHALT DISTRIBUTOR
a.Use equipment for the distribution of asphalt materials equipped with the following: Tachometers; Pressure gauge; Adjustable length spray bars; Separate power unit and pump on the distributing system or hydrostatic drive system; Heating coils and burner; Thermometer well and accurate thermometer; Measuring sticks; and Quick opening gate in the dome. Mount all distributors and supply tanks on trucks or trailers equipped with pneumatic tires. Design the units so that no rutting or other injury to the road surface shall result. Provide sufficient power to maintain the desired speed of the equipment during operation. The tachometer designating the speed of the truck sha ll be a separate operating unit attached to the truck. Equip the tachometer with a large gauge approximately 5.5 inches in diameter and graduated in units so the speed of the truck can be determined within limits of approximately 10 feet per minute. Locate the gauge so that it can be easily read at all times by both the driver and the Engineer. Equip the distributor with either a tachometer attached to the pum p shaft and calibrated to indicate revolution per minute, or a pressure gauge placed in the distributing system and calibra ted to indicate pounds per square inch or gallons per minute by which the flow of asphalt materials can be regulated. The spray bars and nozzles shall be constructed to accomplish the following: Permit adjustment for length in increments of 1 foot for any length up to 16 feet; Permit vertical adjustment of all nozzles to the de sired height above the road surface and conforming to the roadway crown; Permit lateral shifting of the entire spray bar during operation; Prevent clogging of the nozzles; and Provide positive and immediate cut-off when distribution of asphalt material ceases. The power unit and pump distribution system requirements are as follows: Capacity of a minimum of 250 gallons per minute; 155 – ASPHALT SURFACING AND ASPHALT RECYCLING EQUIPMENT
150-12 Equipped with a bypass into the supply tank;
Capable of distributing a uniform and constant flow of asphalt material through all nozzles at a pressure between 30 to 50 pounds per square inch; and Capable of being calibrated and adjusted to accurate ly distribute asphalt mate rial within 0.01 gallon per square yard for any quantity from 0.1 to 1 gallon per square yard.
b.Calibrate and check all distributors before using on a KDOT project. The calibration of the tank and preparation of the certificate shall be pe rformed by the DME in the District in which the distributor is first used. Provide all equipment, materials and a ssistance necessary for the calibration. The DME will give a certificate of approval to the distributor operator indicating the record of the calibration and check. Keep this certificate in the distributor at all times and make it available to the Engineer in charge on each project on which the distributor is used. Failure to present the certificate shall require a re-check, and if deemed necessary, a re- calibration of the distributor before it may be used on a project. The certificate may be revoked at any time due to unsatisfactory performance of the distributor. It shall be returned only when satisfactory repairs or adjustments have been made. Each subsequent year, the operation of the distributor must be checked by the Engineer the first time it is used. When the operation is found to be satisfactory, the distributor may be used. The Engineer making the check will sign and date the certificate. 155.3 STORAGE OR SURGE BINS
a.When a storage or surge bin is used with any type of plant, the following items are required as a minimum.
1.Design, equip and use the bin to prevent segregation.
2.Protect the belt leading from the drum discharge to the bin to prevent heat loss due to wind blowing on the material. (3) Use a “Gob-Hopper” or other type of device approved by the Engineer to help prevent segregation of the mix as it falls into the bin or silo.
4.Use a Tel-Tale device located at the top of the ta pered portion of the bottom of the bin to indicate when the level of the asphalt mixture in the bin has been lowered to that point. In the case of special designed bins (such as full length tapered bins), locate the device at the point designated by the Engineer. Do not lower the mixture below this point except to clean out the bin, when plant operations are being terminated at the end of the day and such other times as deemed necessary by the Engineer. Interconnect the Tel-Tale device with the controls of the gate in the bottom of the bin to close the gate automatically when the mixture in the bi n has been lowered to the level of the Tel-Tale device. Provide a means of over-riding these controls solely for the purpose of cleaning out the bin at the termination of plant operation. The material in the bottom of the bin below the device may be used when the bin is cleaned out, provided the Engineer approves the material. (5) Do not keep hot asphalt mixtures in storage or surge bins longer than 3 hours without prior approval by the Engineer.
b.See subsection 155.6a.(6) for use of surge or storage bins.
c.If the Engineer determines that segregation is occurring, use of storage or surge bins may be prohibited. 155.4 ASPHALT PAVER Acceptable asphalt pavers are self-contained, powe r-propelled units, equipped with an automatically controlled activated screed or strike-off assembly, and he ated if necessary. They ar e capable of spreading and finishing courses of asphalt material in lane widths app licable to the specified section and thickness shown in the Contract Documents. Pavers used for shoulders and similar construction shall be capable of spreading finishing courses of asphalt material to the width shown in the Contract Documents. Equip the paver with an approved automatic screed control system capable of grade reference and transverse slope control. The automatic controls shall in clude a system of sensor oper ated devices that sense and follow a reference line or surfaces on one or both sides of the paver as required. Maintain the screed at the proper 155 – ASPHALT SURFACING AND ASPHALT RECYCLING EQUIPMENT
150-13 elevation at each end by contro lling the elevation of one end while automatically controlli ng the transverse slope, or
by controlling the elevation of each end independently. With the screed or strike-off a ssembly, produce a finished surface of the required evenness and texture without tearing, shoving or gouging the mixture. Equip the paver with a receiving hopper having suffic ient capacity for a unifor m and continuous spreading operation. Equip the hopper with a distribution system to pl ace the mixture uniformly in fr ont of the screed. Pickup attachments used to feed the hopper ma y not exert any vertical load on the pa ver and shall be capable of picking up and loading substantially all of the material on the surface. When laying mixtures, the paver shall be capable of being operated at variable forward speeds consistent with satisfactory laying of the mixture. 155.5 MATERIAL TRANSFER DEVICE Mobile conveyors, shuttle buggies, material transfer vehicles, materials transfer paver and pick-up devices are considered material transfer devi ces. Provide a self-propelled material transfer device, capable of moving independent of the paver or attached to the paver. Equip the materials transfer device to perform additional mixing of the material, and then deposit the mixture into the paver at a uniform temperature and consistency. Paver hopper inserts shall be required when spillage of the HMA occurs during transfer of the material. 155.6 HOT MIX ASPHALT (HMA) PLANTS Plants used for the manufacture of HMA shall consist of a drum mix plant, batch plant or continuous mix plant. Provide equipment complying w ith the requirements specified below, having capacity to adequately handle the proposed asphalt construction, and meeting the approval of the Engineer. Continued use of any hot mix plant is on the condition that the Contractor is fully responsible for producing material that complies with contract requirements.
a.Requirements for All HMA Plants.
1.Uniformity. Design, coordinate and operate the plants to produce a uniform mixture.
2.Proportioning Equipment. The Engineer may require locking or sealing of any automated proportioning equipment that can be manually manipulated.
3.Heating and Storage Tanks for Asphalt Material. Use storage tanks for asphalt material that have sufficient capacity to provide for continuous operation. They shall be capable of uniformly heating and holding the asphalt material at the required temper ature range without damaging or changing its characteristics. Direct flame against the tanks is prohibited. Design the circulating system to obtain proper and continuous circulation during the operating period. Provide an accurate pr ocedure for determining the amount of asphalt material in the tanks at any time. Document and substantiate the calibration data. Situate and construct the tanks so the level of material can be safely and accurately measured at any time. Set the tanks as nearly level as possible. Include a means of obtaining samples of asphalt material from the delivery line to the plant in the system.
4.Cold Feed Aggregate Bins. Provide separate cold feed bins for each aggregate size used, unless blending is permitted by methods approved by the Engineer. Use cold feed bins with sufficient capacity to maintain a continuous flow of material. Construct the bins to prevent any spilling or leakage from one bin to another. Each bin shall have a belt feeder equipped with an adjustable gate or an adjustable drive, or both, that can be calibrated and controlled. Provide a uniform dist ribution of aggregate on the conveyor belt. Equip each bin with a device that shall detect any reduction or interruption of aggregate flow and actuate a visual or audible signal at locations approved by the Engineer.
5.Thermometric Equipment. Equip the plant with a sufficient number of thermometric instruments to control the temperature of the aggregat e and the asphalt material. Use instrume nts capable of recording temperature on a chart over each 24-hour period with a maximum chart gradation of 15 minut es and 10ºF. Use a 24-hour clock or designate AM and PM on the chart. The Engineer shall retain all temperature records as part of the contract records. Install the units separate from the plant in a readily accessible location. Locate the actuating unit for recording temperature either in th e storage tank or in the feed line between the pump and the discharge valve. Locate the actuating unit for recording aggregate temperature and HMA as sp ecified for each type of plant. 155 – ASPHALT SURFACING AND ASPHALT RECYCLING EQUIPMENT
150-14 (6) Use of Storage Bins and Batchers. When used with a storage bin, design and operate these plants so the
transfer of HMA from the drum to the storage bin shall not cause segregation of the mix, and the batcher can be operated according to subsection 602.4a.(3)(d) . Equip all storage bins with controls capable of maintaining a specified minimum level or amount of HMA in the bin at all times during production. If the amount of HMA in the bin can be determined by reading the output of load cells or other approved sensors, the Engineer shall specify the minimum amount of material in tons. Otherwise, the minimum level of HMA is the top of the tapered portion of the bin or at the point designated by the Engineer on special designed bins. Set the controls to close and lock the bin gate when the specified minimum amount or level is reached. Override of the lock is permitted only to clean out the bin at the end of a production run. Equip every storage bin with a batcher at the top, located so the HMA is discharged vertically from the batcher into the center of the bin. The Engineer may approve other equipment such as a rotating chute. Do not load the storage bin directly from a belt or other conveyor. Cover the belts carrying HMA to prevent excess heat loss. Establish control of the batcher gates so the batcher shall operate as specified in subsection 602.4a.(3)(d) throughout the output range of the plant. (7) Dust Collectors. Equip the plant with an approved dust collector, bag house or other type of collector that complies with limit particulate emissions standards. Dispose of all waste mate rial in a suitable manner. Equip the plant to prevent particulate leakage.
8.Air Emission Permit. Provide a copy of an Air Emission Permit issued by the Kansas Department of Health and Environment (KDHE) to the Engineer before installing a hot mix plant. It is the Contractor’s responsibility and expense to satisfy the KDHE requirements.
9.Safety Requirements. Provide adequate and sa fe access to sampling points and other locations where checking of plant operations is necessa ry. Thoroughly guard and protect all gears, pulleys, chains, sprockets and other dangerous moving parts. When required by the Engineer, provide access to the top of truck bodies by a platform or other suitable device to enable the En gineer to obtain samples and temperature data.
b.Requirements for Drum Mix Plants.
1.General. Specifically design the plant for drum mixing and to be capable of satisfactorily heating, drying and mixing the HMA. (2) Cold Aggregate Feed System. Use belt scales for positive weight measurement of the combined cold aggregates. Continuously record the am ount of cold aggregate using a non-se t-back recorder. The belt scale shall be accurate within 2% by weight of th e material being measured over any give n period of time. Calibrate the belt scales at intervals as directed by th e Engineer. Provide a weight system automatically coupled with the asphalt flow to maintain the required proportions.
a.Sampling. Provide safe, adequate and conveni ent facilities for obtaining representative samples of the combined cold aggregate. Provide a sampling device capable of producing a sample of proper size (large enough to be representative, but small enough to be carried safely by 2 people) from the full width of the combined aggregate flow, while the plant is operating at regular production rate.
b.Recycled Material Conveyor. If the plant is used for recycling, a weighing system is required to control delivery of virgin aggregate and recycled material components to the drum. Equip the system with interlocking mechanisms that shall accurately deliver virgin aggregates, Reclaimed Asphalt Pavement (RAP) and Recycl ed Asphalt Shingles (RAS) in proper proportions. Belt scales for the RAP and RAS shall comply with subsection 155.6b.(2) .
c.Moisture Compensation. Include a moisture compensation device in the cold feed system to correct for the moisture in the aggr egate passing over the belt scales.
d.Weather Protection. Prot ect belt scales from the effect of wind and weather.
3.Asphalt Material Feed System. Supply asphalt material to the mixing drum through a continuously registering cumulative indicating meter by a pump specifically designed for drum mix plants. Locate the meter in the asphalt material so it shall register the discharge to the drum. Provide a means to divert the flow into a container for calibration. Supply the meter with a non-set-back re gister accurate within 2% by weight of the material measured in any given period of time. The register shall record only material delivered to the drum.
4.Mineral Filler Feed System. Introduce and uniform ly disperse fly ash and similar mineral fillers into the drum mixer at the point of introduction of the asphalt without loss to the dust collector system. Use a non-set-back register to record the quantity of mineral filler disc harged into the mixer. Equip the delivery system with
Source: Kansas Standard Specifications for State Road and Bridge Construction, 2015 Edition. Pages 106–110 of 978.