LIME-TREATED COURSES

307.01 Description

Construct one or more courses of non-sulfate soil or soil-aggregate mixed with lime and water.

307.02 Material

Provide materials as specified in:

Cutback Asphalt Subsection 702.01(B) Emulsified Asphalt Subsection 702.01(C)

Water Subsection 714.01(A)

Hydrated Lime Subsection 714.03(A)

Quicklime Subsection 714.03(B)

307.03 Construction

A. Construct according to the class specified.

1. Class 1 stabilization and construction operations:

a. Spread the first increment of lime.

b. Perform initial mixing.

306.03 Construction

Scarify the roadbed, including shoulders, to the specified depth and width. Pulverize the scarified material so that a minimum of 95 percent, excluding gravel or stone, passes a 2-in.

(50-mm) sieve.

Compact as specified in Subsection 304.03(D).

306.04 Measurement

The Engineer will measure work acceptably completed as specified in Subsection 109.01.

306.05 Payment

The Agency will pay for accepted quantities at the contract unit price as follows:

Pay Item Pay Unit

(A) Reconditioning existing base and surface station, mi (km), yd² (m²)

Such payment is full compensation for furnishing all equipment, tools, labor, and incidentals necessary to complete the work as specified.

SECTION 307

LIME-TREATED COURSES

307.01 Description

Construct one or more courses of non-sulfate soil or soil-aggregate mixed with lime and water.

307.02 Material

Provide materials as specified in:

Cutback Asphalt Subsection 702.01(B) Emulsified Asphalt Subsection 702.01(C)

Water Subsection 714.01(A)

Hydrated Lime Subsection 714.03(A)

Quicklime Subsection 714.03(B)

307.03 Construction

A. Construct according to the class specified.

1. Class 1 stabilization and construction operations:

a. Spread the first increment of lime.

b. Perform initial mixing.

c. Cure the mixed material.

d. Spread the second increment of lime.

e. Perform final mixing.

f. Compact to required density and finish.

2. Class 2 stabilization and construction operations:

a. Spread the specified percentage of lime.

b. Perform initial mixing.

c. Cure the mixed material.

d. Perform final mixing.

e. Compact to required density and finish.

3. Class 3 stabilization and construction operations:

a. Spread the specified percentage of lime.

b. Perform mixing.

c. Compact to required density and finish.

B. Preparing the Roadbed. Grade the roadbed surface to the specified lines, grades, and cross sections. Dispose of excess material as specified in Subsection 201.03.

Prevent water from ponding in the roadbed. Remove and replace unstable subgrade.

C. Scarifying and Pulverizing. Scarify the roadbed to the specified depth and width and pulverize the scarified material to 100 percent passing a 3-in. (75-mm) sieve. Remove unsuitable soil and organic materials.

D. Applying Lime. Apply hydrated lime or quicklime at the specified rates. Apply hydrated lime as a slurry or in a dry form. Apply quicklime only in a dry form. Mix quicklime thoroughly with the dry roadbed material before adding water; add water to the mixture within 6 hours of dry mixing.

Operate only essential equipment on the spread lime until mixing is complete.

Ensure the lime is uniformly incorporated within ±[0.5] percent of requirement.

Apply lime only on unfrozen foundation and when the temperature in the shade is 40°F (5°C) or higher during application and mixing.

E. Adding Water. Add water and thoroughly mix. Ensure moisture content does not exceed 3 percent over the optimum as determined by AASHTO T 99.

line, grade, and cross section. For Class 1 and 2 stabilization, seal the surface with a roller. For Class 3 stabilization, compact and finish.

G. Curing and Final Mixing (Class 1 and 2 Stabilization). Cure the mixture at least three days for hydrated lime and two days for quick lime. Keep the stabilized layer moist during curing. Reprocess surfaces that become dusty or dry during the curing period.

After the curing period, scarify the stabilized layers and, for Class 1 stabilization, reapply lime. Remix the layer to the specified moisture content. Continue mixing until 100 percent of the material, except stone and gravel, passes a 2-in. (50-mm) sieve, and 60 percent passes a No. 4 (4.75-mm) sieve. Seal the surface after mixing with a pneumatic-tired roller.

H. Compacting and Finishing. Complete final compacting and finishing operations within 12 hours of the final mixing. Compact the mixture to a minimum of 95 percent of the maximum density as determined by AASHTO T 99 Method C. Remove all equipment imprints and use a pneumatic-tired roller for final finish rolling.

The Engineer will determine in-place density according to AASHTO T 191 or T 310, correcting for oversized particles according to AASHTO T 224 as necessary.

I. Surface Tolerance. Finish the surface so that deviations do not exceed ¹/₂ in. (15 mm), longitudinal or transverse, when tested according to Subsection 401.03(K)(1).

J. Protecting and Curing. Restrict operation of vehicles or equipment on the treated course for a minimum 7-day cure period after final finish rolling. Unless the contract specifies an asphalt curing seal, keep the surface lightly moistened during the curing period to prevent drying.

Apply an asphalt curing seal as specified in Section 405.

Protect and maintain the subgrade surface until covered. Construct at least one course of base or subbase on the treated subgrade before using it for hauling operations.

Protect the course from freezing for at least [5] days after placement.

307.04 Measurement

The Engineer will measure work acceptably completed as specified in Subsection 109.01 and as follows:

A. The Engineer will use manufacturer’s package net weight (mass) to measure sacked lime.

307.05 Payment

The Agency will pay for accepted quantities at the contract unit price as follows:

Pay Item Pay Unit

(A) Lime ton (Mg)

(B) Processing lime-treated course (Class___, ___ in. (mm) thick)

mi (km), yd² (m²)

Such payment is full compensation for furnishing all materials, equipment, labor, and incidentals to complete the work as specified.

The Agency will base payment for quicklime upon a 90 percent available lime index calculated as percent calcium oxide (CaO) by weight.

The Agency will base payment for hydrated lime upon a 90 percent available lime index calculated as percent calcium hydroxide (Ca(OH)2) by weight.

SECTION 308