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SECTION 32 11 28
SECTION 32 11 28
COLD RECYCLED ASPHALT BASE
| PART 1 | GENERAL |
| 1.1 | SECTION INCLUDES |
| A. | Mill existing asphalt material to required depth and width. |
| B. | Mix with emulsified asphalt, quick lime slurry, and water if required, place to line and grade and compact. |
| 1.2 | REFERENCES |
| A. | AASHTO T 26: Quality of Water to be Used in Concrete |
| B. | AASHTO T 166: Bulk Specific Gravity of Compacted Bituminous Mixtures Using Saturated Surface-Dry Specimens |
| C. | AASHTO T 245: Resistance to Plastic Flow of Bituminous Mixtures Using Marshall Apparatus |
| D. | ASTM C 110: Standard Test Methods for Physical Testing of Quicklime, Hydrated Lime, and Limestone |
| E. | ASTM C 977: Standard Specification for Quicklime and Hydrated Lime for Soil Stabilization |
| F. | ASTM D 2950: Test Method for Density of Bituminous Concrete in Place by Nuclear Method |
| 1.3 | SUBMITTALS |
| A. | Submit mix design for Engineer’s approval prior to starting cold recycling operation. |
| B. | Provide a Manufacturer’s Certificate of Compliance for Quick Lime. |
| 1.4 | ACCEPTANCE |
| A. | The Contractor shall run five density tests on each test lot. |
| 1. | A test lot is defined as the amount of cold recycled material placed during one full day’s production. |
| 2. | Each density test consists of the mean of three in-place nuclear wet density tests. ASTM D 2950. |
| 3. | Establish the target density by obtaining a sample of loose material from the roadway just ahead of the rolling operation. |
| a. | Heat sample in oven at 140 degrees F for two hours maximum. |
| b. | Compact mix immediately using standard 50 blow Marshall procedure. AASHTO T 245. |
| c. | The target for roadway compaction is 96 percent of the mean of 3 Marshall briquettes for each test lot. AASHTO T 166. |
| B. | The COR verifies the surface with a 10-ft straightedge at selected sites. Correct surface variations in excess of ⅜ inch by removing or adding material. |
| 1.7 | PAYMENT PROCEDURES |
| A. | Include all costs for quick lime slurry in the Cold Recycled Asphalt Base. |
PART 2 PRODUCTS
| 2.1 | MATERIALS |
| A. | Cold Recycled Asphalt Base gradation: |
| Sieve |
| Percent Passing by Weight |
| B. | Use asphalt emulsion as shown on the plans. Refer to Section 32 12 03. |
| C. | Use high calcium pebble quick lime (Hot hydrated lime slurry) that has a minimum dry solids content of 35 percent by weight and that is a pumpable suspension of solids in water. Quick lime slurry must conform to ASTM C 977 using test method ASTM C 110. |
| D. | Use 1.5 percent quick lime by weight of cold recycled base. |
| E. | Use potable water for the quick lime slurry. Refer to AASHTO T 26. |
| 2.2 | EQUIPMENT |
| A. | Use self-propelled equipment with sufficient power, traction and stability to maintain an accurate depth of cut. |
| B. | Use equipment that will process full depth and lane width in one pass, with screening and crushing capability. |
| C. | Use a machine capable of mixing the pulverized material, emulsified binding agent, and quick lime slurry to a homogeneous mixture. |
| D. | Provide lime slurry equipment that accurately proportions quick lime and water, mixes these ingredients to obtain proper slaking, and maintains a uniform, homogenous slurry. Agitate slurry sufficiently to prevent separation while transporting. Add the lime slurry to the pulverized surfacing by a spray bar at the cutting head on the mill. Accurately meter the slurry into the recycled materials. |
| E. | Use a mixing machine capable of placing the mixed material into a windrow or directly into the hopper of a paver. |
| F. | Separate machinery may be used for mixing. |
| G. | Use a positive displacement pump capable of accurately metering the required quantity of additive down to a minimum rate of 4 gallons per minute. |
| H. | Use a mixing machine that has a meter capable of measuring the flow and total delivery of the additive. |
| I. | Use a machine capable of picking up the entire windrow when a pick-up machine is used to feed the paver. |
| J. | Use 30-ton minimum pneumatic rollers. |
PART 3 EXECUTION
| 3.1 | PREPARATION |
| A. | Clean or clear away all debris and vegetation within 1 ft of pavement edge. |
| 3.2 | RECLAIMED MATERIALS | |
| A. | Crush or screen the reclaimed material to pass a 1½ inch sieve. |
| B. | Reclaimed material must be free of organic materials, soil, or other foreign substances. | |
| 3.3 | PLACEMENT |
| A. | Place the mixed material with a self-propelled asphalt paver. |
| B. | Adjust emulsion content as pavement conditions change. Repair reclaimed materials when surface ruts or ravels before placement of final wearing surface. |
| C. | Use watering device to prevent materials from adhering to the tires for breakdown or intermediate rolling. |
| D. | Add water to milled material as necessary to facilitate uniform mixing. |
| E. | Continue breakdown rolling until no displacement is noted. |
| F. | Use steel wheel rollers in static or vibratory mode as required for final rolling. |
| G. | Wait 72 hours after a rain or confirm that moisture content is less than 1.5 percent before placing flush, tack, or final surfacing on cold recycled material. |
| 3.4 | LIMITATIONS | |
| A. | Do not disturb underlying crushed aggregate base. |
| B. | Do not heat screed. |
| C. | Do not park roller or leave idle on uncompacted recycled surface. |
| D. | Perform recycling operations when ambient temperature exceeds 50 degrees F in the shade and pavement temperature exceeds 70 degrees F. Stop recycling operations when weather is foggy or rainy. | |
| E. | Prohibit traffic on compacted recycled material for 2 hours after compacting is completed. Remove all loose aggregates by power brooming before allowing traffic on the compacted recycled material. | |
END OF SECTION
COLD RECYCLED ASPHALT BASE Page 2
