315Cement Stabilized Reclaimed Base Construction (CSRB)

Base Construction (CSRB)

315.1General Description

This work includes constructing a cement stabilized base course by pulverizing the existing flexible pavement, underlying base and subgrade, and mixing with Portland cement. Construct according to these specifications and to the lines, grades, thickness, and typical cross-sections shown on the plans or established by the Engineer. 315.1.01 Related References General Provisions 101 through 150

GDT 19 – Determining Maximum Density of Soil-Cement mixtures GDT 20 – Determining Field Density of soils with <45% retained on the No. 10 sieve and < 10% retained on the 1 in. sieve GDT 21 - Determining Field Density of soils containing >45% retained on the No.10 sieve or >10% retained on the 1 in. sieve GDT 59 - Testing Density of roadway materials with Nuclear Gauge GDT 65 – Laboratory Design of Soil-Cement and Cement Stabilized Graded Aggregate GDT 67 – Family of Curves Method for determining Maximum Density of soils GDT 86 – Determining the compressive strength of Cement Stabilized Base cores taken from the roadway 334 334 334 334 334 334 334 334 334

315.1.02 Submittals Prior to construction, submit a Construction Work Plan to the Engineer consisting of the proposed equipment, materials, and operation procedures. If the Engineer determines that the work plan is not satisfactory, revise the procedures and augment or replace equipment, as necessary, to complete the work. 315.1.03 Mix Design The Contractor shall submit a mix design to the Office of Materials and Testing for approval at least three weeks prior to construction. The Mix Design process shall be completed in accordance with GDOT Test Method/GDT 65 by an accredited materials laboratory. The sampling, testing, proportioning, and documentation shall be completed by an accredited materials laboratory. The Contractor will be responsible for ensuring that appropriate traffic control measures are in place during the sampling operations. In-place samples of the road structure shall be taken at a minimum frequency of 1000 ft. (300m) per two lanes; alternating the sample locations to achieve a sample every 500 lane-feet (152m). Additional samples may be needed to represent material changes and/or problem areas. Each sample shall contain at least 30 lbs. (14kg) of proportionally blended materials to be reclaimed. The Portland cement used in the design process must be from an approved source listed on GDOT’s Qualified Products List/QPL3 and representative of the same material to be used in construction. The mix design submittal to the Office of Materials and Testing shall include the following:

the roadway.

target gradation of the blended material, optimum moisture content of mixing, and application rate of the stabilizer to meet the design requirements. Note: Since the Mix Design is based on source specific materials, any changes to materials or sources will render the design invalid.

315.2Materials

Ensure that materials meet the requirements of the following GDOT Standard Specifications: Material Section Blotter material (sand) 412.3.05.G.3 Soil Base Material 814.2.02 Cutback asphalt, RC-30, RC-70, RC-250 or MC-30, MC-70, MC-250, CSS-1h, AE-P, CRS-2 821.2.01 Portland Cement (Type I or Type II) 830.2.01 Water 880.2.01 335 335 335 335 335 335 335 335 335

315.3Construction Requirements

315.3.01 Personnel Ensure that only experienced and capable personnel operate equipment. 315.3.02 Equipment Equipment used in CSRB construction must meet the following requirements and be approved by the Engineer prior to the beginning of construction. All equipment shall be in satisfactory condition and capable of its intended purpose. The Engineer may at any time reject any equipment that is deemed unsafe, erratic, or produces an inadequate performance. Note: Equipment type, size, operation and condition are subject to the Engineer’s approval and must be adjusted and/or replaced upon their request.

CSRB will require a reclaimer unit that meets the following requirements:

granular/soil base, Subbases, and subgrade down to depths of at least 12 in. (300mm).

and has automatic sensors to monitor water application and mixing depth.

For CSRB construction, use a cyclone-type mechanical spreader or its equivalent that will spread Portland cement in a relatively dust-free process. Spreader must have an electronic or mechanical metering system which monitors the application rate. Note: The use of pneumatic tubes to transfer cement or lime directly onto the roadway will not be allowed.

Additional equipment necessary to complete the work must be in satisfactory condition and proper for its intended purpose. Compactive equipment includes a sheep’s foot roller, vibratory steel wheel roller and a pneumatic rubber tire roller. Use the correct size/type rollers or combination thereof that is capable of achieving the required density. A pressure distributor that complies with GDOT Standard Specifications/Subsection 424.3.02.B will be required to apply the bituminous prime coat. Note: Equipment type, size, operation and condition are subject to the Engineer’s approval and must be adjusted and/or replaced upon their request. 315.3.03 Preparation Prior to commencing reclaiming operations, blade grass and excess soil a minimum of 12 in. (300mm) from the edge of pavement. Locate, mark and preserve existing centerline, manholes, and utilities (gas, water, and electric lines). Relocate mailboxes and other appurtenances within such proximity to the roadway as to risk damage or interfere with the work. Remove sections of driveway aprons in the right-of-way where necessary to permit the reclaimer to operate without damaging the machinery or driveway pavement. If necessary, saw-cut a neat parallel line to the proposed edge of pavement and remove the concrete along the road. After all work is complete, replace appurtenances to their original location as nearly as possible. 336 336 336 336 336 336 336 336 336

315.3.04 Construction

Adjust the moisture content of the roadway materials to within 100 to 120 percent of the optimum moisture immediately before spreading the cement. The optimum moisture content is determined by the Job Mix Design and can be adjusted by the Engineer.

shown on the Plans. The Engineer may alter the spread rate during the progress of construction if necessary. Maintain the application rate within + 10 percent of that specified by the Engineer.

cement shall be checked by using a square yard cloth/certified scales and by determining the overall coverage area of each tanker. Multiple checks may be necessary to ensure that the spread rate is maintained within the ± 10 percent limit.

affected area within the tolerance specified, make necessary adjustments to the spreader, and perform additional checks to ensure the problem is corrected. If the cement content is more than the 10 percent limit in the mixing area, the excess quantity will be deducted from the Contractor’s pay for cement.

compacting, and finishing operations can be completed within the required time limits.

does not displace cement.

mixture is produced. The Engineer at any time may require adjustments or replacement of equipment if a homogeneous and uniform mixture conforming to these Specifications is not achieved.

requirements:

immediately after the preliminary mixing of the cement and roadway material.

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the test section will be determined by area in which the entire tanker of cement will cover.

and finished base surface. If the Engineer deems necessary, revise the compaction procedure or replace equipment.

cement was added to the mixture.

between 100 and 120 percent of the optimum moisture content.

alternate method is approved by the Engineer.

established on the Job Mix Design.

cement-treated materials in order to conform to cross-sectional or grade requirements.

or deformations, and conforming to the proper line, grade, and cross-section.

the Engineer. Apply the same compaction requirements as stated above in Subsection 315.3.04.E.4.

stabilized base course again with a pneumatic-tired roller.

loose or shattered material.

of the day’s work, or at the point of interruption.

is impractical to complete the full width during one day’s work. Use the procedure for forming a straight

transverse joint. Remove all waste material from the compacted base. 338338338338338338338338338

surface moisture is adequate.

no case later than 24 hours after completion of the finishing operations.

of an adjoining section to prevent marring or damaging of the completed work. Protect the stabilized area

from freezing during the curing period.

GDOT Standard Specifications/Subsection 300.3.06.B whenever defects appear. This preservation action

does not relieve the Contractor of his responsibility to maintain the work until final acceptance as specified in

GDOT Standard Specifications/Section 105.

315.3.05 Quality Acceptance

Test Method/GDT 19 or GDT 67.

GDT 59 as soon as possible after compaction, but before the cement sets.

stated above in Subsection 315.3.04.D.2.

non-super elevated sections.

not exceed ½ in. (12.5mm) at any point. 339339339339339339339339339

determine the average thickness, but not less than one check per 1000 ft. (300m) per 2 lanes. Checks shall be

taken after the completion of the base course and prior to priming.

isolate the affected area. Correct any area deficient by more than ½ in. (12.5mm) to the design thickness by

using one of the following methods:

No payment will be made for any Asphaltic Concrete 9.5mm Superpave used to correct deficiencies nor will

pavement be made for removing and reconstructing the deficient work.

isolate the affected area. If the basis of payment is per cubic yard and the average thickness for any mile

increment exceeds the allowable ½ in. (12.5mm) tolerance the excess quantity in that increment will be

deducted from the Contractor’s payments. The excess quantity is calculated by multiplying the average

thickness that exceeds the allowable ½ in. (12.5mm) tolerance by the surface area of the base, as applicable.

315.4Measurement

Measure the surface length along the centerline when payment is specified by the square yard. The width is

specified on the plans. Measure irregular areas, such as turnouts and intersections, by the square yard.

Measure Portland cement by the ton.

Bituminous prime is not measured for separate payment. Include the cost of furnishing and applying bituminous

prime according to the provisions of GDOT Standard Specifications/Section 412 in the Unit Price Bid for each

individual base item.

315.5Payment

Cement-stabilized base, in-place and accepted, will be paid for at the Contract Unit Price per square yard.

Payment will be full compensation for roadbed preparation, mixing on the road, shaping, pulverizing, watering,

compaction, defect repair, bituminous prime and maintenance.

Portland cement will be paid for at the Contract Unit Price per ton. Payment is full compensation for furnishing,

hauling, and applying the material. Only Type I or Type II Portland cement incorporated into the finished course

will be paid for and no payment will be made for cement used to correct defects due to the Contractor’s

negligence, faulty equipment, or error. 340340340340340340340340340

Payment will be made under:

Item No. 315 Cement Treated Base Course Per square yard (meter)

Item No. 315 Portland Cement Per ton (megagram)) 341 341 341 341 341 341 341 341 341