312.01 262 SECTION 312 – AGGREGATE -LIME-FLY ASH STABILIZED BASE COURSE
312.01 Des cription ................................ ................................ ................... 262
312.02 Materials ................................ ................................ ...................... 262
312.03 Proportioning ................................ ................................ ............... 263
312.04 Equipment ................................ ................................ .................... 264
312.05 Limitations ................................ ................................ ................... 266
312.06 Subg rade Preparation ................................ ................................ ... 266
312.07 Mixing ................................ ................................ .......................... 266
312.08 Spreading ................................ ................................ ..................... 267
312.09 Compaction ................................ ................................ .................. 267
312.10 Finishing ................................ ................................ ...................... 267
312.11 Constr uction Joints ................................ ................................ ....... 268
312.12 Thickness and Surface Requirements ................................ ........... 268
312.13 Curing ................................ ................................ .......................... 268
312.14 Traffic and Maintenance ................................ .............................. 268
312.15 Method of Measurement ................................ .............................. 268
312.16 Basis of Payment ................................ ................................ .......... 269
DESCRIPTION
312.01 Description
This work consists of constructing a base of mineral aggregate, hydrated lime, and fly ash . MATERIALS
312.02 Materials
Provide materials as specified in: Crushed Limestone Aggregate Type A, Grading C ............... 903.05 Bituminous Material for Curing Emulsified Asphalt, Types allowed for Tack Coat in 403 ............................... 904.03 312.03 263 Water ................................ ................................ ..................... 921.01 Lime ................................ ................................ ....................... 921.04 Provide emulsified asphalt, of a type allowed for Tack Coat in 403, meeting the test requirements specified in Table 904.03-1. Fly Ash shall meet the requirements of 921.15.
312.03 Proportioning
Proportion the lime, fly ash, and aggregate to meet the limits specified in Table 312.03 -1. Table 312.03-1: Proportioning of Lime, Fly As h, and Aggregate Mix Material Range of Percent by Weight of Total Dry Mix Lime 3.5 Fly Ash 11.0 Aggregate 85.5 The mixture shall be within plus or minus 2% of the optimum moisture of the mixture, as determined according to AASHTO T 99, Method C (with replacement). Design the mixture so that when compacted into cylinders, cured and tested according to ASTM C593, the cylinders will have a minimum average compressive strength of 950 psi and no individual test is lower than 800 psi. At least 45 days before producing the stabilized mixture, submit the following for the Engineer’s approval:
1.Mix design,
2.Statement naming the source and percentage of each component, and
3.Report showing the results of the applicable tests meeting the above requirements. For material testing and verification of the mix design, submit component materials in the quantities specified in Table 312.03 -2. 312.04 264 Table 312.03-2: Material Quantities for Mix Verification Testing Material Quantity (pounds) Hydrated Lime 25 Fly Ash 50 Aggregate 200 The Engineer may choose to verify the mix design on an annual basis provided the properties and proportions of the materials do not change appreciably. Adhere to the approved proportions of material during the progress of the wo rk. Do not change the source or character of any material without the Engineer’s approval, which will be based on verification of the new mix design. EQUIPMENT
312.04 Equipment
A.Mixing Plant Provide a stationary or portable batch or continuous mix type mixing plant that is equipped to allow the Engineer to verify the component percentages at any time.
1.Stationary or Portable Batch Type Plants. Equip mixing plants with batching devices and sca les to proportion the individual components by weight. Ensure that such devices have the accuracy needed to maintain the material percentages, based on total dry weight, within the tolerances specified in Table 312.04-1. 312.04 265 Table 312.04 -1: Tolerances for Mi x Components (based on dry weight) Material Tolerance Hydrated Lime ± 0.25% Fly Ash ± 0.75% Water ± 2.0% Equip stationary or portable batch type plants with scales as specified in 501.04.A.3 . Use separate scales and hoppers for weighing the aggregate and the lime and the fly ash; however, the fly ash may be weighed cumulatively in the weigh hopper with the lime, provided the lime is added first.
2.Continuous Type Mixing Plants. Equip continuous type mixing plants with:
1.Metering devices and scales for proportioning the lime and fly ash by weight to meet the tolerances specified in Table 312.04-1;
2.An out-of-range alarm system that will sound an audible alarm when the lime or fly ash is not within the established tolerances;
3.A meter or other approved regulating device to control the flow of water into the plant in a manner that positively maintains a uniform moisture content in the mixture; and
4.A separate, quick, and automatically operating on -off device to shut the water off instantly when the mixer stops. Maintain a n approved method of checking and calibrating the weighing system in an easily accessible location on the plant.
B.Rollers Provide either pneumatic tire or vibratory type rollers as specified in 407.07. 312.05 266 C. Spreader Provide either a self -propelled or tractor -drawn spreader that can maintain a uniform rate of travel while spreading and of laying a lift of uniform consistency and thickness with proper grade control.
D.Haul Trucks Transport the mixture from the central pl ant in clean trucks equipped with tight metal rear -end dump beds having a cover of canvas, or other suitable material, securely fastened on all sides of the truck bed, and of such size as to maintain the moisture content and prevent the loss of fines. CONSTRUCTION REQUIREMENTS
312.05 Limitations
The Contractor may perform stabilization from March 1 through September 30, and may continue this operation from October 1 through November 30 provided that Type I Portland cement is substituted for the lime on a pound for pound basis. Do not perform stabilization when the aggregate or the surface on which the base course is to be placed is wet or frozen, when it is raining, sleeting, or snowing, or when the temperature is 40 °F or less. Do not begin processing o perations for this material unless the air temperature in the shade is at least 40 °F and rising. Cover the aggregate -lime-fly ash stabilized base course with the succeeding stage of base or pavement construction before December 15.
312.06 Subgrade Prepa ration
Prepare the subgrade as specified in 205, 207, or 302, whichever is applicable.
312.07 Mixing
Mix the aggrega te with the proper amount of lime, fly ash, and water in an approved mixer. Continue mixing until a thorough and uniform mixture is obtained. Handle the aggregate in a manner that will prevent contamination and segregation. Ensure that the plant will di scharge the mixture without undue segregation. 312.08 267 312.08 Spreading After mixing, transport the material to the site while it contains the proper moisture content, and spread the material to the required th ickness and cross - section using an approved spreader. If the required compacted depth of the base exceeds 8 inches, construct the base in two or more approximately equal layers. The maximum compacted thickness of any one layer shall not exceed 8 inches.
312.09 Compaction
The Contractor may use any type of compacting equipment that will produce the required result. At the start of compaction, the percentage of moisture in the mixture based on oven dry weight shall not vary more than 3% above or 1% below the specified optimum moisture. Extend rolling over the edges of the base material onto the shoulders. The Department will divide the completed base into lots of approximately 10,000 square yards fo r density testing purposes, and will perform five density tests on each lot. The average dry density of each lot shall be not less than 100% of the maximum density as determined according to AASHTO T 99, Method C (with replacement), and no individual test shall be less than 97% of the maximum density. If the specified density is not obtained, rework or replace the material to comply with the density requirement at no additional cost to the Department. The Engineer may employ a control strip and random sam pling to evaluate and adjust the Contractor’s compaction procedure. Provide a sufficient number of compaction and finishing units to ensure that the initial compaction of the processed section of the stabilized base course is completed within 4 hours from the time the water is added at the mixer. The final finishing and compaction shall be within 8 hours from the time of mixing. The Engineer may extend this time if the material has not reached an initial set. If, for any reason, construction operations a re delayed or suspended and the Engineer requires the removal and disposal of loose or uncompacted material, the Contractor shall perform this work at no additional cost to the Department. No aggregate -lime-fly ash base course may be salvaged.
312.10 Finishing
Perform finishing operations as specified in 304.09. 312.11 268 312.11 Construction Joints Construct joints as specified in 309.09.
312.12 Thickness and Surface Requirements
Meet the thickness and surface requirements specified in 309.10.
312.13 Curing
After finishing the aggregate -lime-fly ash base, seal the surface with one of the bituminous materials specified in 312.02, applied by a pressure distributor at the rate of 0.10 to 0.25 gallons per squ are yard or as directed by the Engineer. Heat or otherwise prepare the bituminous material to ensure uniform distribution. Apply the material no later than 24 hours after completing finishing operations unless the Engineer determines that application sho uld be delayed. Keep the finished base continuously moist until the bituminous curing seal has been applied. Maintain the curing material during a 7 -day protection period so that all the aggregate -lime-fly ash base course will be covered effectively duri ng this period. Until the mixture has cured for 7 days, only allow on the base the pneumatic -tired equipment required for applying the curing seal. However, provide ingress and egress for property owners before the 7 -day curing period .
312.14 Traffic an d Maintenance
The Contractor may open portions of completed base to traffic as specified in 304.14. Maintain the completed base as specified in 304.15. COMPENSATION
312.15 Method of Measurement
The Department will measure bituminous material for curing seal and the mineral aggregate, lime, and fly ash mixture by the ton in accordance with 109. The Department will deduct the weight of total moisture in the aggregate, as determined by dry weights, of the base material at the time of weighing in excess of 3% of optimum moisture. The Department will not measure and 312.16 269 pay for mixing water; however, it will measure and pay for water added on the road at the direction of the Engineer by the M.G. (1,000 gallons) in accordance with 109.
312.16 Basis of Payment
The Department will pay for accepted quantities at the contract prices as follows: Item Pay Unit Mineral Aggregate Ton Lime Ton Fly Ash Ton Bituminous Material Ton Water MG If fly ash is substituted with cement it will not result in additional cost to the Department. 313.01 270 SECTION 313 – TREATED PERMEABLE BASE
313.01 D escription ................................ ................................ ................... 270
313.02 Materials ................................ ................................ ...................... 270
313.03 Composition of Mixtures ................................ ............................. 271
313.04 Equipment ................................ ................................ .................... 271
313.05 Construction Requirements ................................ .......................... 272
313.06 Limita tions ................................ ................................ ................... 273
313.07 Surface Requirements ................................ ................................ .. 273
313.08 Tolerance in Pavement Thickness ................................ ................ 273
313.09 Method of Measurement ................................ .............................. 274
313.10 Basis of Payment ................................ ................................ .......... 274
DESCRIPTION
313.01 Description
This work consists of constructing treated permeable base, composed of either a mixture of aggregate, Portland cement, and water, or a mixture of aggregate with asphalt binder, on a prepared sub -base. The Contractor may use either cement treated or asphal t treated permeable base. MATERIALS
313.02 Materials
Provide materials as specified in: Portland Cement, Type I ................................ ........................ 901.01 Aggregate for Portland Cement Treated Mixture .................. 903.03 Aggregate for Bituminous Tre ated Mixture ........................... 903.06 Asphalt Cement, Grade PG 64 -22, 70-22, 76-22, 82-22 ........ 904.01 Liquid Membrane – Forming Compounds ............................. 913.05 Water ................................ ................................ ...................... 921.01
Source: Tennessee Standard Specifications for Road and Bridge Construction, 2021 Edition. Pages 271–278 of 1,072.