32 11 29.pdf

Tinker AFB, OK TAFB Technical Specifications 2019

April 2019 Page 1 Section 32 11 29

SECTION 32 11 29

LIME-STABILIZED SUBGRADE

Part 1 GENERAL

1.1 REFERENCES

The publications listed below form a part of this specification to the extent referenced. The publications are referred to in the text by basic designation only. Current editions of references at time of delivery order shall be used.

AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM)

ASTM C 50 (1994) Sampling, Inspection, Packing, and

Marking of Lime and Limestone Products

ASTM C 136 (1996a) Sieve Analysis of Fine and Coarse Aggregates

ASTM D 422 (1963; R 1998) Particle-Size Analysis of

Soils

ASTM D 698 (1998) Laboratory Compaction Characteristics of Soil Using Standard Effort (12,400 ft-lbf/cu. ft. (600 kN-m/cu.m.))

ASTM D 977 (1998) Emulsified Asphalt

ASTM D 2922 (1996el) Density of Soil and Soil-

Aggregate in Place by Nuclear Methods (Shallow Depth)

ASTM D 4318 (1998) Liquid Limit, Plastic Limit, and

Plasticity Index of Soils

ASTM E 11 (1995) Wire-Cloth Sieves for Testing Purposes

1.2 DEFINITIONS

1.2.1 Lime-Stabilized Course

Lime-stabilized course, as used in this specification, is a mixture of lime and in-place or select borrow material uniformly blended, wetted, and thoroughly compacted to produce a pavement course which meets the criteria set forth in the plans and this specification.

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1.2.2 Degree of Compaction

Degree of compaction required is expressed as a percentage of the maximum density obtained by the test procedure presented in ASTM D 698 abbreviated as percent laboratory maximum density.

1.3 SUBMITTALS

1.3.1 Government approval is required for all submittals. The following shall be submitted in accordance with

SECTION 01 33 00; SUBMITTAL PROCEDURES:

SD-03 Product Data SD-04 Samples SD-06 Tests Reports SD-07 Certificates

SD-09 Manufacturer Reports SD-10 Operation Data

1.3.2 Sampling and Testing: Field Density.

1.3.3 Calibration curves and related test results prior to using the device or equipment being calibrated.

1.3.4 Copies of field test results within 24 hours after the

tests are performed.

1.4 PLANT, EQUIPMENT, MACHINES, AND TOOLS

1.4.1 General Requisites

Equipment, plant, and tools used in the work shall be subject to approval by the Contracting officer and shall be maintained in a satisfactory working condition. Protective equipment, apparel, and barriers shall be provided to protect the eyes, respiratory system, and the skin of workers exposed to contact with lime dust or slurry.

1.4.2 Mixing Equipment

Traveling plants shall be approved types of either the single or multiple pass type that will thoroughly pulverize and mix the materials of the mix to the required size and uniformity. The plant shall have the capacity so that the subgrade will not be rutted or damaged.

The plant shall have provisions for introducing water or other liquids at the time of mixing through a metering devise or other approved methods. Leakage of liquids from the equipment shall be corrected before proceeding further. The single pass machine shall be designed to pick up the material to be mixed for a window or blanket and shall be equipped so that curing at least

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50 percent of the mixing cycle all the material is picked up and mixed while separated from the mixing table.

1.5 SAMPLING AND TESTING

An approved commercial testing laboratory shall perform sampling and testing. Tests shall be performed to sufficient numbers and at the locations and time directed to ensure that materials and compaction meet specified requirements. Copies of the test results shall be furnished to the Contracting Officer.

1.5.1 Samples

Samples of lime shall be taken in accordance with ASTM C 50.

1.5.2 Testing

1.5.2.1 Field Density

Field density tests shall be in accordance with ASTM D 2922. At least one field density test shall be performed for each 500 square yards of each layer of base material.

1.5.2.2 Sieve Analysis

Before starting work, at least one sample of material to be stabilized shall be tested in accordance with ASTM C 136 and ASTM D 422 on sieves conforming to ASTM E 11. Results shall verify that the material complies with the specification. After the initial test, a minimum of one (1) analysis shall be performed for each 1000 tons of material placed, with a minimum of three

(3) analysis for each day's run until the course is completed.

When the source of materials is changed or deficiencies are found, the initial analysis shall be repeated and the material already placed shall be retested to determine the extent of unacceptable material. All in-place unacceptable material shall be replaced.

1.5.2.3 Liquid Limit and Plasticity Index

One liquid limit and plasticity index shall be performed for each sieve analysis. Plasticity index shall be in accordance with

ASTM D 4318.

1.5.2.4 Smoothness

Measurements for deviation from grade and cross section shown shall be taken in successive positions parallel to the road centerline with 10 - foot straight edge. Measurements shall also be taken perpendicular to the road centerline at 50 - foot intervals.

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1.5.2.5 Thickness

Measurements shall be made in 3-inch diameter test holes penetrating the treated course.

1.5.2.6 Laboratory Density

Tests shall be established the dry weight on treated soil at optimum moisture content and shall provide density relationship for the lime soil mixture. Tests shall be conducted in accordance with ASTM D 698.

1.6 RATES OF APPLICATIONS

The rate of application of lime for soil lime mixture shall be at least 6 percent by dry weight of the non-treated soil.

Bituminous material for curing shall be uniformly applied at the rate of 0.1 to 0.4 gallon per square yard. The Contracting Officer will determine the exact bituminous material quantities, which may be varied to suit field conditions.

1.7 WEATHER LIMITATIONS

Lime shall not be applied when the atmospheric temperature is less than 40 degrees F. No lime shall be applied to soils that are frozen or contain frost. If the temperature falls below 35 degrees F., completed lime treated areas shall be protected against any detrimental effects of freezing.

Part 2 PRODUCTS

2.1 MATERIALS

2.1.1 Lime

Lime shall be a standard brand of hydrated lime conforming to the following physical and chemical requirements:

a. Lime shall be of such gradation that 99-1/2 percent passes a

No. 20 sieve and a minimum of 85 percent passes a No. 100 sieve. Graduation of pelletized quicklime shall be such that 100 percent will pass the 3/4-inch sieve.

b. Combined calcium oxide and magnesium oxide shall be not less than 92 percent.

2.1.2 Bituminous Material

Material shall be emulsified asphalt ASTM D 977, Type RS-1 or RS- 2 Emulsified asphalt shall be diluted with 50 percent water prior to application.

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2.1.3 Material to be Stabilized

Material shall be free of deleterious substances such as sticks, debris, organic matter, and stones greater than 3 inches in any dimension.

2.1.4 Water

Water shall be clean, fresh, and free from injurious amounts of oil, acid, salt, alkali, organic matter, and other substances deleterious to the lime or soil-lime mixture, and shall be subject to approval by the Government Construction Inspector.

Part 3 EXECUTION

3.1 PREPARATION OF AREA FOR STABILIZATION

All roads and pavement areas to be lime treated shall be prepared to approximate subgrade elevations in accordance with Section 31 23 06; EXCAVATION, EMBANKMENT AND PREPARATION OF SUBGRADE FOR ROADWAYS AND PARKING LOTS. Adequate drainage shall be provided during the entire construction period to prevent water from collecting or standing on the area or on pulverized mixed, or partially mixed material. Line and grade stakes shall be provided as necessary for control. The area shall be cleaned of debris. The area shall be capable of the compaction specified for the soil lime mixture. Debris and removed unsatisfactory in-place material shall be disposed of as specified. The entire area shall be graded to conform to the lines, grades, and cross sections shown. Soft or yielding subgrade area shall be made stable before construction is begun.

3.2 INSTALLATION

3.2.1 Scarifying and Pulverizing of Soil

Prior to application of lime, the in-place soil shall be scarified to a depth of 6 inches and pulverized as necessary with no stones or lumps larger than 2 1/2 inches in any dimension to a sufficient width and depth to obtain a uniform mixture of soil, lime, and water and to form a compacted subgrade conforming to the cross section indicated. Scarification shall be carefully controlled so that the layer beneath the layer to be treated is not disturbed.

3.2.2 Edges of Stabilized Course

Approved material shall be placed along the edges of the stabilized course in a quantity that will compact to the thickness of the course being constructed, or to the thickness of each layer in a multiple-layer course, allowing at least a 1 foot

April 2019 Page 6 Section 32 11 29 width of the shoulder to be rolled and compacted simultaneously with the rolling and compacting of each layer of the stabilized course.

3.2.3 Application of Lime

Pulverized material shall be shaped to approximately the cross section indicated. Lime shall be applied at the specified rate.

Mechanical spreaders shall be used in applying bulk lime.

Equipment used for spreading lime shall be approved type, which will distribute the lime at controlled uniform rates.

Distributors shall be used in applying slurry. If lime is spread by hand, the bags shall be spotted so that when the bags are opened the lime will be dumped and spread uniformly on the area being processed. No equipment except that used in spreading and mixing shall pass over the freshly applied lime.

3.2.4 Initial Mixing

Immediately after the lime has been distributed, the lime and soil shall be mixed. Initial mixing shall be sufficient to alleviate any dusting or wetting of the lime that might occur in the event of the final water application and mixing. When proper mixing has been accomplished, the mixture shall be left to cure prior to final mixing. Curing time when hydrated lime is used shall be 72 hours of temperature above 32 degrees F (0 degrees C). Curing time when quick lime is used shall be 48 hours of temperature above 32 degrees F (0 degrees C). During the curing period the material shall be maintained in a moist condition.

3.2.5 Water Application and Final Mixing

Moisture content of the mixture shall be determined prior to final mixing and water shall be added as required. Moisture in the mixture following final mixing shall be between optimum and 3 percent above optimum. Water shall be incrementally incorporated and simultaneously intermixed into the soil. After the last portion of water has been added, mixing shall be continued until the water is uniformly distributed throughout the full depth of the mixture. Particular care shall be taken to ensure satisfactory moisture distribution along the edges of the section.

3.2.6 Layer Thickness

The compacted thickness of the established aggregate base course shall be as indicated on the drawings when a compacted layer of inches is specified the material maybe placed in a single layer.

When a compacted thickness of more than 6 inches is required, no single layer of the placed material shall be in excess of 6 inches nor less than 3 inches when compacted.

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3.2.7 Finishing

The surface shall be finished to the grade and cross section shown. The surface shall be of uniform texture. Should the surface for any reason become rough, corrugated, uneven in texture, or traffic marked prior to completion, such unsatisfactory portions shall be scarified, reworked, re-laid, or replaced. Should any portion of the course, when laid, become water soaked for any reason, that portion shall be removed immediately, and the mix placed in a window and aerated until a moisture content within the limits specified is obtained, and then spread, shaped, and rolled as specified above.

3.2.8 Thickness Control

Completed thickness of the subgrade course shall be not more than 1/2 inch below the thickness indicated. Where more than 1/2 inch deficient, such areas shall be corrected by scarifying, adding proper mixture, re-blading, and re-compacting as determined by the Contracting officer. The average of all thickness measurements taken for the job shall be within 1/4 inch of the thickness indicated

3.2.9 Construction Joints

At the end of each phase of construction, a straight transverse construction joint shall be formed by cutting back into the completed work to form a true vertical face, free of loose or shattered material. Material along construction joints not properly compacted shall be removed and replaced with soil lime mixture that is mixed, moisture, and compacted as specified.

3.2.10 Curing

Immediately after finishing the surface shall be protected against rapid drying by bituminous material curing. Emulsified asphalt bituminous material shall be uniformly applied at a rate of 0.1 and 0.4 gallons per square yard by means of a bituminous distributor at a temperature within the following ranges:

Emulsified Asphalt Degrees F

RS-1 ______________________________________ 75-130

RS-2 ______________________________________ 110-160

Areas inaccessible to or missed by the distributor shall be properly treated using the manually operated hose attachment. At the time the bituminous material is applied, the surface of the area shall be free of loose or foreign matter. When necessary, the area shall be sprinkled immediately before the bituminous material is applied.

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3.2.11 Protection

Completed portions of the subgrade may be opened immediately to light traffic proved the curing is not impaired. After the curing period, completed area may be opened to all traffic, provided the course has hardened sufficiently to prevent marring or distorting of the surface by equipment or traffic. Heavy equipment shall not be permitted on the area during the curing period. Lime and water may be hauled over the completed area with pneumatic tired equipment used in constructing an adjoining section shall be protected in manner to prevent equipment from marring or damaging completed work.

3.3 MAINTENANCE

The subgrade shall be maintained in a satisfactory condition until the completed work is accepted. Maintenance shall be repeated as often as necessary to keep the area intact. Defects shall be corrected as specified herein.

3.4 DISPOSAL OF UNSATISFACTORY MATERIALS

Remove in-place materials that are unsuitable for stabilization.

Material that is removed to correct defective areas, waste material, and debris shall be disposed of as approved by the Contracting officer.

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