304Lime Treatment

Lime Treatment

304.01DESCRIPTION. Construct one or more courses of a mixture of

lime, soil, or soil-aggregate, and water in accordance with these specifications and Table 304-2, in conformity with the lines, grades, thickness and sections shown on the plans. Lime treatment will be designated as Type B, C, D, or E. Use Type B for base or subbase. Use Type C for conditioning for cement treatment or stabilization. Use Type D for working table treatment under or within an embankment. Use Type E for conditioning and drying of subgrades under a base course.

304.02MATERIALS. Materials shall comply with the following

sections and subsections: Emulsified Asphalt Section 1002 Water 1018.01 Lime 1018.02 Quality assurance requirements shall be as specified in the latest edition of the Department’ s publication titled Application of Quality Assurance Specifications for Embankment and Base Course. Submit a dust control plan to address weather, sight clearance, operational procedures, traffic control, and any other project specific concerns. Failure to maintain sight clearance will result in the engineer stopping contractor operations. The Department will identify dust sensitive areas in the plans. In these specific areas, the dust control plan must also include environmental requirements. In order to meet air quality standards, the contractor may be required to use central plant mixing, lime -slurry, or granular lime in dust sensitive areas at no direct pay.

304.03EQUIPMENT. Furnish and maintain equipment necessary to

produce a finished product meeting specification requirements. Use an approved in-place mixer meeting the requirements of 303.03 for Type B and C treatments. Use an approved in-place mixer meeting the requirements of 303.03 for Types D and E treatments unless the engineer allows other equipment.

304.04GENERAL CONSTRUCTION REQUIREMENTS. Protect

dry lime from moisture prior to use. Add water as needed during mixing and remixing operations, during the curing period, and to keep the cured material uniformly moist until covered. When applying granular quicklime in dry form, take precautions to prevent injury to persons, livestock, and plants. Immediately collect quicklime spilled or deposited outside areas designated for treatment and bury or satisfactorily slake. Do not apply lime on a frozen foundation or when the ambient air temperature is below 35°F.

.1 Type B Treatment: Incorporate lime in the following

sequence: Spread the lime; initially mix; water; seal and mellow for at least 48 hours; and then mix until pulverization requirements are met; compact; finish; and maintain in accordance with 304.09. Determine the percent of lime for Type B treatment in accordance with DOTD TR 416. After lime treatment, the treated soil shall have a maximum Liquid Limit of 40 and a maximum PI of 10.

.2 Type C Treatment: Incorporate lime in the following

sequence: Spread the lime; initially mix; water; seal and mellow for a minimum of 48 hours; then mix until pulverization requirements are met; compact; finish; and maintain. The percent of lime for Type C treatment will be as required by the plans or as directed.

.3 Type D Treatment: Spread and mix one increment of

lime with materials to be treated, water as required, and compact to the satisfaction of the engineer. The percent of lime for Type D treatment will be as required by the plans or as directed.

.4 Type E Treatment: Spread and mix one increment of lime

with materials to be treated and compacted, and finish in accordance with treatment in accordance with DOTD TR 416.

304.05SPREADING AND MIXING. Incorporate the specified

percentage of lime. When not specified, the District Laboratory will determine the required percentage of lime in accordance with DOTD TR 416. Use a unit weight of 35 pounds per cubic foot to compute the required application rate of hydrated lime or granular quicklime regardless of the actual unit weight of the lime used. Furnish lime in bags or bulk and distribute in powder or granular form or as slurry in the required proportion. Prevent dry lime from blowing by adding water or by other suitable means. Uniformly spread lime and mix with the soil to the width and depth shown on the plans or as directed. The Department will determine lime spread rate in accordance with DOTD TR 436. Discontinue any procedure that results in excessive loss or displacement of lime. Process areas on the same day that lime application is made. Reject any lime not processed within 6 hours and lime lost or damaged before incorporation due to rain, wind, or other cause, and deduct from measured quantities. Replace all rejected lime. Payment will not be made more than once for lime treatment of a section of roadway.

.1 Type B Mixing: After the 48-hour mellowing period, keep

the lime treated mixture moist and manipulate with an in-place mixer until the pulverization requirements of 304.06 have been met.

.2 Type C Mixing: After the 48-hour mellowing period,

thoroughly manipulate the lime treated mixture with an in-place mixer to the satisfaction of the engineer. The mixture shall meet the pulverization requirements of 304.06 prior to subsequent stabilization or treatment with portland cement.

.3 Types D and E: Mix with an in-place mixer unless the

engineer approves other equipment.

304.06PULVERIZATION. For Types B and C treatment, the pulverized

mixture, when tested in accordance with DOTD TR 431, shall meet the gradation requirements in Table 304-1. Table 304-1 Gradation Requirements for Types B & C Lime Treatment

3/4 95 No. 4 50 Meet pulverization requirements for Type B and C treatments prior to final compaction and finishing.

304.07COMPACTING AND FINISHING

.1 Type B: After meeting the pulverization requirement,

uniformly compact the mixture to at least 95.0 percent of maximum dry density. Determine the maximum dry density in accordance with DOTD TR 415 or TR 418 and in-place density in accordance with DOTD TR 401. Complete compaction and finishing operations within 6 hours after meeting pulverization requirements. The Department will perform one density test per 1000 linear feet of roadway (or 2000 linear feet) of shoulder constructed separately in accordance with DOTD TR 401. At places inaccessible to rollers, such as edges adjacent to curb and gutter sections, compact the mixture using devices that will obtain uniform compaction to required density without damage to adjacent structures. Reconstruct any section not meeting the required density in accordance with these specifications at no direct pay. Reconstruction shall include the addition of the specified amount of lime. The final finish shall meet grade and cross-slope requirements and shall have a smooth, uniform, closely-knit surface, free from ridges, waves, loose material, or laitance.

.2 Type C: Shape and uniformly compact Type C lime

conditioned materials to the required sections. Uniformly compact the mixture to at least 93.0 percent of maximum dry density. Determine the maximum dry density in accordance with DOTD TR 415 or TR 418 and in- place density in accordance with DOTD TR 401. When conditions, such as a yielding subgrade, make this impractical or detrimental, establish an optimum rolling pattern to the satisfaction of the engineer.

.3 Type D: Uniformly compact and finish Type D lime treated

materials to the satisfaction of the engineer. Make reasonable efforts to conform to the compaction requirements of 304.07.1. When conditions, such as a yielding subgrade, make this impractical or detrimental, establish an optimum rolling pattern to the satisfaction of the engineer.

.4 Type E: Compact and finish Type E lime treated materials

in accordance with Section 203. When traffic conditions warrant, and an adequate rolling pattern has been established that demonstrates density has been achieved, the engineer may reduce density frequency testing requirements to expedite construction. A change in subgrade materials will require testing at the original frequency until a new rolling pattern is established.

304.08QUALITY CONTROL. Construction methods shall prevent

contamination, segregation, soft spots, wet spots, laminations, and other deficiencies. Perform such tests as necessary to adequately control the work. Construct a completed course that is uniform and conforms to the acceptance requirements.

304.09PROTECTION, CURING, AND MAINTENANCE. Maintain

these treatments to prevent damage to the lime treated layer as directed. For Type B Treatment, protect the material against rapid drying for 72 hours by applying an asphalt curing membrane, complying with Section 506, after finishing operations have been completed. Place the application immediately following smooth rolling and maintain it adequately during the curing period. Maintain Type B Lime Treatment in accordance with 303.09.

304.10DIMENSIONAL TOLERANCES (TYPE B TREATMENT)

.1 General: The Department will check thickness and width

of completed lime treated courses for acceptance in accordance with DOTD TR 602. Delineate areas not meeting tolerances specified herein and correct to plan dimensions by scarifying, adding lime, remixing, and recompacting deficient areas at no direct pay.

.2 Thickness Requirements: Do not allow under-thickness

to exceed 3/4 inch and over-thickness to exceed 1 inch.

.3 Width Requirements: Do not allow roadway base course

width to vary from plan width in excess of +6 inches. Shoulder base course width shall not vary from plan width in excess of +3 inches. No under-widths are allowed for shoulder or roadway bases. When the base course for roadway and shoulders are constructed at the same time, the 6-inch width tolerance will be applied. Correct base course width deficiencies in excess of foregoing tolerances at no expense to the Department.

304.11MEASUREMENT. Lime will be measured by the ton. When

furnishing lime in bags, the number of bags used and the weight per bag will be used for measurement. When furnishing lime in bulk, the contractor shall furnish certified weights for each transport load. The quantities of lime treatment for payment will be the design areas as specified on the plans and adjustments thereto. Design quantities are based on the horizontal dimensions of the completed lime treatment shown on the plans. Design quantities will be adjusted if the engineer makes changes to adjust to field conditions, design errors are proven, or design changes are necessary. Water and asphalt curing materials will not be measured for payment.

304.12PAYMENT. Payment for lime will be made at the contract unit

price per ton. If using quicklime in a slurry, payment will be made at the unit price for hydrated lime after converting the quicklime to the equivalent weight of hydrated lime by multiplying the weight of quicklime by 1.32 and then multiplying that product by the purity of the lime. Payment for lime treatment will be made at the contract unit prices per square yard. Type B lime treatment will be adjusted as specified in Section 506 and Section 1002 for specification deviations of asphalt curing membrane. The Materials and Testing Section will provide the payment adjustment percentage for properties of asphalt materials. Payment will be made under: Item No. Pay Item Pay Unit

304-01Lime Ton

304-02Lime Treatment (Type B) ___ in Thick Square Yard

304-03Lime Treatment (Type C) ___ in Thick Square Yard

304-04Lime Treatment (Type D) ___ in Thick Square Yard

304-05Lime Treatment (Type E) ___ in Thick Square Yard

Table 304-2 Types of Lime Treatment B Base or Subbase

period

membrane C Conditioning for Cement Treatment or Stabilization

period

D Working Table

E Conditioning and Drying (Subgrades Under a Base Course)

requirements including density

1 In-place mixer shall be required. 2 In-Place mixer shall be required unless the engineer approves other equipment.