Article 1 — Description
Mix and compact lime, water, and subgrade or base (with or without asphaltic concrete pavement) in the roadway.
Article 2 — Materials
Furnish uncontaminated materials of uniform quality that meet the requirements of the plans and specifications. Notify the Engineer of the proposed material sources and of changes to material sources. Obtain verification from the Engineer that the specification requirements are met before using the sources. The Engineer may sample and test project materials at any time before compaction. Use material definitions in accordance with Tex -100-E .
2.1 Lime . Furnish lime that meets the requirements of DMS -6350 , “Lime and Lime Slurry .” When dry lime is
required, provide dry quicklime. When lime slurry is required, provide commercial lime slurry or quicklime slurry. Do not use dry quicklime when sulfates are present in quantities greater than 3, 000 parts per million (ppm). When furnishing quicklime, provide it in bulk.
2.2 Subgrade . The Engineer will determine the sulfate content of the subgrade in accordance with Tex -145-E
and organic content in accordance with Tex-148-E before lime treatment begins. Suspend operations when material to be treated has a sulfate content greater than 7, 000 ppm or an organic content greater than 2 .0%, unless otherwise directed.
2.3 Flexible Base. Unless otherwise shown on the plans, furnish base material that meets the requirements of
Item 247, “Flexible Base,” for the type and grade shown on the plans, before the addition of lime. Unless otherwise shown on the plans, the compressive strength of the flexible base is waived.
2.4 Water . Furnish water free of industrial wastes and other objectionable material.
2.5 Asphalt . When asphalt or emulsion is permitted for curing purposes, furnish materials that meet the
requirements of Item 300, “Asphalts, Oils, and Emulsions,” as shown on the plans or as directed.
2.6 Mix Design . The Engineer will determine the target lime content and optimum moisture content in
accordance with Tex -121-E or prior experience with the project materials. The Contractor may propose a mix design developed in accordance with Tex-121-E . The Engineer will use Tex -121-E to verify the Contractor’s proposed mix design before acceptance. Reimburse the Department for subsequent mix designs or partial designs necessitated by changes in the material or requests by the Contractor. Limit the amount of recycled asphalt pavement to no more than 50% of the mix , unless otherwise shown on the plans or directed.
Article 3 — Equipment
Provide machinery, tools, and equipment necessary for proper execution of the work. Provide rollers in accordance with Item 210, “Rolling.” Provide proof rollers in accordance with Item 216, “Proof Rolling,” when required.
3.1 Storage Facility. Store quicklime in closed, weatherproof containers.
3.2 Slurry Equipment. Use slurry tanks equipped with agitation devices to slurry quicklime on the project or
other approved location. The Engineer may approve other slurrying methods. 178 Provide a pump for agitating the slurry when the distributor truck is not equipped with an agitator. Equip the distributor truck with a sampling device in accordance with Tex -600-J , Part I, when using commercial lime slurry.
3.3 Hydrated Lime Distribution Equipment . Provide equipment to spread lime evenly across the area to be
treated. Provide equipment with a rotary vane feeder to spread lime, when shown on the plans.
3.4 Pulverization Equipment . Provide pulverization equipment that:
cuts and pulverizes material uniformly to the proper depth using cutters that plane to a uniform surface over the entire width of the cut, provides a visible indication of the depth of cut at all times, and uniformly mixes the materials.
Article 4 — Construction
Construct each layer uniformly, free of loose or segregated areas, and with the required density and moisture content. Provide a smooth surface that conforms to the typical sections, lines, and grades shown on the plans or as directed.
4.1 Preparation of Subgrade or Existing Base for Treatment . Before treating, remove existing asphalt
concrete pavement in accordance with Item 105, “Removing Treated and Untreated Base and Asphalt Pavement ,” when shown on the plans or as directed. Shape existing material in conformance with applicable bid items to conform to typical sections shown on the plans and as directed. Unless otherwise approved, proof roll the roadbed in accordance with Item 216 before pulverizing or scarifying existing material. Correct soft spots as directed. When material is imported from a borrow source, notify the Engineer of the location of the borrow source well in advance to allow time for testing and approval to avoid delay to the project. Stockpile as directed. The Engineer will test the borrow source and determine the sulfate and organic contents. When the borrow source has a sulfate content greater than 3, 000 ppm or an organic content greater than 2 .0%, proceed as directed. When new base material is required to be mixed with existing base, deliver, place, and spread the new material in the required amount per station. Manipulate and thoroughly mix new base with existing material to provide a uniform mixture to the specified depth before shaping.
4.2 Pulverization . Pulverize or scarify existing material after shaping. If the material cannot be uniformly
processed to the required depth in a single pass, excavate and windrow the material to expose a secondary grade to achieve processing to plan depth.
4.3 Application of Lime . Uniformly apply lime using dry or slurry placement as shown on the plans or as
directed. Add lime at the percentage determined in accordance with Section 260.2.6., “Mix Design.” Apply lime only on an area where mixing can be completed during the same working day. Start lime application only when the air temperature is at least 35°F and rising or is at least 40°F. The temperature will be taken in the shade and away from artificial heat. Suspend application when the Engineer determines that weather conditions are unsuitable. Minimize dust and scattering of lime by wind. Do not apply lime when wind conditions, in the opinion of the Engineer, cause blowing lime to become dangerous to traffic or objectionable to adjacent property owners. When pebble grade quicklime is placed dry, mix the material and lime thoroughly at the time of lime application. Use of quicklime can be dangerous. Inform users of the recommended precautions for handling and storage. 179 4.3.1. Dry Placement . Before applying lime, bring the prepared roadway to approximately two percentage points above optimum moisture content. When necessary, sprinkle in accordance with Item 204, “Sprinkling.” Distribute the required quantity of pebble grade quicklime using approved equipment.
4.3.2 Slurry Placement . Provide slurry free of objectionable materials, at or above the minimum dry solids
content, and with a uniform consistency that will allow ease of handling and uniform application. Deliver commercial lime slurry to the jobsite or use quicklime to prepare lime slurry at the jobsite or other approved location, as specified. When dry quicklime is applied as slurry, use 80% of the amount shown on the plans. Distribute slurry uniformly by making successive passes over a measured section of roadway until the specified lime content is reached. Uniformly spread the residue from quicklime slurry over the length of the roadway being processed, unless otherwise directed.
4.4 Mixing . Begin mixing within 6 hr. of application of lime. Lime exposed to the open air for 6 hr. or more
between application and mixing, or that experiences excessive loss due to washing or blowing, will not be accepted for payment. Thoroughly mix the material and lime using approved equipment. When treating subgrade, bring the moisture content above the optimum moisture content to ensu re adequate chemical reaction of the lime and subgrade materials. Ensure 100% of the material passes a 2- 1/2 in. sieve, except rock, before mellowing. Allow the mixture to mellow for 1 –4 days, as directed. When pebble grade quicklime is used, allow the mixture to mellow for 2– 4 days, as directed. Sprinkle the treated materials during the mixing and mellowing operation, as directed, to achieve adequate hydration and proper moisture content. When the material to be treated has a sulfate content greater than 3, 000 ppm but less than or equal to 7, 000 ppm, mellow for a minimum of 7 days. Maintain in a continuously moist condition by sprinkling in accordance with Item 204. After mellowing, resume mixing until a homogeneous, friable mixture is obtained. After mixing, the Engineer may sample the mixture at roadway moisture and test in accordance with Tex -101-E , Part III, to determine compliance with the gradation requirements shown in Table 1. Table 1 Gradation Requirements (Min % Passing) Sieve Size Base Subgrade 1-3/4” 100 100 3/4” 85 85 #4 – 60
4.5 Strength Testing. The Engineer will sample and test the lime- treated mixture for unconfined compressive
strength in accordance with Tex -117-E , Part II. The unconfined compressive strength must be greater than 50 psi for lime- treated subgrade and 150 psi for lime- treated flexible base or lime- treated flexible base with existing material, unless otherwise shown on the plans.
4.6 Compaction. Compact the mixture using density control, unless otherwise shown on the plans. Multiple lifts are permitted when shown on the plans or approved. Bring each layer to the moisture content directed.
Sprinkle the treated material in accordance with Item 204, or aerate the treated material to adjust the moisture content during compaction so that it is no more than 1.0% below optimum and 2.0% above optimum as determined in accordance with Tex-121-E . Begin rolling longitudinally at the sides and proceed toward the center, overlapping on successive trips by at least one- half the width of the roller unit. On superelevated curves, begin rolling at the low side and progress toward the high side. Offset alternat ing trips of the roller. Operate rollers at a speed between 2 and 6 mph as directed. Before final acceptance, the Engineer will select the locations of tests in each unit and measure the treated depth in accordance with Tex -140-E . Correct areas deficient by more than 1/2 in. in thickness or more than 1/2% in target lime content by adding lime as required, reshaping, recompacting, and refinishing at the Contractor’s expense. 180 Rework, recompact, and refinish material that fails to meet or that loses required moisture, density, s tability, or finish before the next course is placed or the project is accepted. Continue work until specification requirements are met. Rework in accordance with Section 260.4. 7., “Reworking a Section.” Perform the work at no additional expense to the Department.
4.6.1 Ordinary Compaction. Roll using approved compaction equipment, as directed. Correct irregularities,
depressions, and weak spots immediately by scarifying the areas affected, adding or removing treated material as required, reshaping, and recompact ing.
4.6.2 Density and Moisture Control . Compact to at least 95% of the maximum density, and moisture content no
more than 1.0% below optimum and 2.0% above optimum as determined in accordance with Tex-121-E , unless otherwise shown on the plans. Provide the Engineer with the beginning and ending station numbers of the area completed for testing. The Engineer will determine roadway density and moisture content of completed sections in accordance with Tex-115-E , Part I. The Engineer will determine random locations for testing in accordance with Tex-115-E , Part IV. When the density is less than 95% of the maximum dry density, the Engineer may perform additional testing to determine the extent of the area to correct. The Engineer may accept the section if no more than one of the five most recent density tests is below the specified density and the failing test is no more than 3 pcf below the specified density.
4.7 Reworking a Section . When a section is reworked within 72 hr. after completion of compaction, rework the
section to provide the required density. When a section is reworked more than 72 hr. after completion of compaction, add additional lime at 25% of the percentage determined in accordance with Section 260.2.6., “Mix Design.” Reworking includes loosening, adding material or removing unacceptable material if necessary, mixing as directed, compacting, and finishing. When density control is specified, determine a new maximum density of the reworked material in accordance with Tex -121-E , and compact to at least 95% of this density.
4.8 Finishing. Immediately after completing compaction of the final course, clip, skin, or tight -blade the surface
of the lime- treated material using a maintainer or subgrade trimmer to a depth of approximately 1/4 in. Remove loosened material and dispose of at an approved location. Roll the clipped sur face immediately using a pneumatic tire roller until a smooth surface is attained. Add small amounts of water as needed during rolling. Shape and maintain the course and surface in conformity with the typical sections, lines, and grades shown on the plans or as directed. Finish grade of constructed subgrade to within 0.1 ft. in the cross -section and 0.1 ft. in 16 ft. measured longitudinally . Correct grade deviations of constructed base greater than 1/4 in. in 16 ft. measured longitudinally or greater than 1/4 in. over the entire width of the cross -section in areas where surfacing is to be placed. Remove excess material, reshape, and roll using a pneumatic -tire roller. Correct as directed if material is more than 1/4 in. low. Do not surface patch. The 72- hr. time limit required for completion of placement, compaction, and finishing does not apply to finishing required just before applying the surface course.
4.9 Miscellaneous and Small Areas . Miscellaneous areas are those that typically involve handwork or
discont inuous paving operations, such as temporary detours, driveways, mailbox turnouts, crossovers, gores, spot level -up areas, and other similar areas. Miscellaneous and small areas are not subject to density testing but may be tested as directed.
4.10 Curing. Cure for the minimum number of days shown in Table 2 by sprinkling in accordance with Item 204,
or by applying an asphalt material at a rate of 0.05– 0.20 gal. per square yard, as shown on the plans or as directed. Maintain moisture during curing. Upon completion of curing, maintain the moisture content in accordance with Section 132.3.5., “Maintenance of Moisture and Reworking,” for subgrade and Section 247.4.5., “Curing, ” for bases before placing subsequent courses. Do not allow equipment on the finished course during curing except as required for sprinkling, unless otherwise approved. Apply seals or additional courses within 14 calendar days of final compaction. 181 Table 2 Min Curing Requirements before Placing Subsequent Courses1 Untreated Material Curing (Days ) PI ≤35 2 PI >35 5 1. Subject to approval. Proof rolling may be required as an indicator of adequate curing.
Article 5 — Measurement
5.1 Lime . When lime is furnished in trucks, the weight of lime will be determined on certified scales, or the
Contractor must provide a set of standard platform truck scales at an approved location approved. Scales must meet the requirements of Item 520, “Weighing and Measuring Equipment.”
5.1.1 Commercial Lime Slurry . Lime slurry will be measured by the ton (dry weight) as calculated from the
minimum percent dry solids content of the slurry, multiplied by the weight of the slurry in tons delivered.
5.1.2 Quicklime .
5.1.2.1. Dry. Lime will be measured by the ton (dry weight) of the quicklime. 5.1.2.2. Slurry . Lime slurry will be measured by the ton (dry weight) of the quicklime used to prepare the slurry multiplied by a conversion factor of 1.28 to determine the quantity of equivalent hydrated lime, which will be the basis of payment.
5.2 Lime Treatment . Lime tre atment will be measured by the square yard of surface area. The dimensions for
determining the surface areas are established by the widths shown on the plans and the lengths measured at placement.
Article 6 — Payment
The work performed and materials furnished in accordance with this Item and measured as provided under “Measurement” will be paid for in accordance with Section 260.6.1., “Lime,” and Section 260.6.2., “Lime Treatment.” Furnishing and delivering new base will be paid for in accordance with Section 247.6.2., “Flexible Base (Roadway Delivery).” Mixing, spreading, blading, shaping, compacting, and finishing new or existing base material will be paid for under Section 260.6.2., “Lime Treatment.” Removal and disposal of existing asphalt concrete pavement will be paid for in conformance with pertinent Items or in accordance with Article 4.4., “Changes in the Work.” Sprinkling and rolling, except proof rolling, will not be paid for directly , but will be subsidiary to this Item, unless otherwise shown on the plans. When proof rolling is shown on the plans or directed by the Engineer, it will be paid for in accordance with Item 216. Where subgrade is constructed under this Contract, correction of soft spots in the subgrade or existing base will be at the Contractor’s expense. Where subgrade is not constructed under this Contract, correction of soft spots in the subgrade or existing base will be paid for in accordance with pertinent Items or Article 4.4., “Changes in the Work.” Where subgrade to be treated under this Contract has sulfates greater than 7,000 ppm, work will be paid for in accordance with Article 4.4., “Changes in the Work.” Asphalt used solely for curing will not be paid for directly , but will be subsidiary to this Item. Asphalt placed for curing and priming will be paid for under Item 310, “Prime Coat.” 182 6.1. Lime . Lime will be paid for at the unit price bid for “Quicklime (Dry)” or “Commercial or Quicklime (Slurry).” This price is full compensation for materials, delivery, equipment, labor, tools, and incidental s. Lime used for reworking a section in accordance with Section 260.4. 7., “Reworking a Section,” will not be paid for directly , but will be subsidiary to this Item.
6.2 Lime Treat ment . Lime treatment will be paid for at the unit price bid for “Lime Treatment (Existing Material),”
“Lime Treatment (New Base),” or “Lime Treatment (Mixing Existing Material and New Base),” for the depth specified. No payment will be made for thickness or width exceeding that shown on the plans. This price is full compensation for shaping existing material, loosening, mixing, pulverizing, spreading, applying lime, compacting, finishing, curing, curing materials, blading, shaping and maintaining shape, replacing mixture, disposing of loosened materials, processing, hauling, preparing secondary subgrade, water, equipment, labor, tools, and incidentals.