405.01 405-1 HEATING AND SCARIFYING TREATMENT DESCRIPTION
405.01 This work consists of recycling the top portion of the existing asphalt pavement as
shown in the Contract, by cleaning, heating, scarifying , redistributing, re -leveling, compacting, and rejuvenating the existing asphaltic material. MATERIALS
405.02 Asphalt rejuvenating agent shall meet the requirements of subsection 702.02(f).
CONSTRUCTION REQUIREMENTS
405.03 Weather limitations shall be as provided in subsection 401.07. Before commencing
heating and scarifying operations, the pavement shall be cleaned of all loose material. Power brooms shall be supplemented by hand brooming and use of other tools as required to bring the surface to a clean, suitable condition free of deleterious material. Equipment used to heat and scarify the asphalt surface shall meet the following requirements:
1.Capable of uniformly applying heat under totally insulated, enclosed hoods to produce radiant heat.
2.Self-propelled and capable of scarifying to the depth specified.
3.Capable of covering a minimum of 750 square yards per hour while heating the existing surface to the extent that it will be remixed by the scarifiers to a depth not less than specified. The heating operation shall extend at least 4 inches beyond the width of scarifying on both sides. When a pass is made adjacent to a previously placed mat, the longitudinal seam shall extend at least 2 inches into the previously placed mat. The temperature of the scarified material shall be between 200 and 300 ºF when measured immediately behind the scarifier. The scarified material shall be distributed and leveled by a paving machine. The paving machine shall be capable of screed ing the full width of the scarified material to produce a uniform cross section as shown in the Contract. While the scarified material is still hot and before it is placed by the paving machine, an application of asphalt rejuvenating agent shall be applied as specified. The asphalt surface shall be compacted immediately after it has been distributed and leveled, and while it is still workable. Two rollers shall be used to compact the scarified material. A steel wheel roller shall be used first to provide breakdown rolling, followed by a pneumatic tire roller with a minimum weight of 12 tons, to complete compaction to 92 to 96 percent of maximum theoretical density. When the mixture surface temperature falls below 165 ºF , no further compaction effort shall be done unless approved. A minimum of 24 hours shall elapse before an asphalt pavement overlay is applied to the scarified pavement. 405.04 405-2 The weight per cubic foot of the existing asphalt surface shall be determined per AASHTO T 166. Scarification depth will be acceptable when the moving average of a minimum of three consecutive random tests per hour indicates that the required amount per square foot, based on the weight per cubic foot of the existing asphalt surface, has been scarified. Testing shall be performed by the Contractor in lots of three per hour, or as often as necessary to maintain process control. The longitudinal surface smoothness of the roadway before and after heating and scarifying shall be tested per subsection 105.07(f). METHOD OF MEASUREMENT
405.04 Heating and scarifying treatment will be measured by the square yard of work
completed and accepted. BASIS OF PAYMENT
405.05 The accepted quantities of heating and scarifying treatment will be paid at the
contract unit price per square yard for heating and scarifying treatment, and shall include cleaning, heating, scarifying, redistributing, re- leveling, and compacting the existing asphalt surfacing. Payment will be made under: Pay Item Pay Unit Heating and Scarifying Treatment Square Yard Asphalt rejuvenating agent will be measured and paid for per Section 411. 406.01 406-1 SECTION 406 COLD ASPHALT PAVEMENT (RECYCLE) DESCRIPTION
406.01 This work consists of pulverizing the existing asphalt surfacing to the depth shown on
the plans, mixing a recycling agent and water, if required, with the pulverized material, then spreading and compacting the mixed material. MATERIALS
406.02 The recycling agent shall be either a high float emulsified asphalt (polymerized) or
emulsified recycling agent meeting the requirements of subsection 702.02(e). The pulverized material shall meet the following gradation requirements: Table 406 -1 COLD ASPHALT PAVEMENT (RECYCLE) PULVERIZED MATERIAL GRADATION REQUIREMENTS Sieve Size Percent Passing 31.5 mm (1 1/4 inch) 100 25.0 mm (1 inch) 90-100 The sealing emulsion shall be high float emulsion (diluted), emulsified asphalt (SS), or approved equal. CONSTRUCTION REQUIREMENTS
406.03 Weather Limitations . Daily recycling operations shall not begin until the atmospheric
temperature is 55 ºF and rising. Recycling operations shall be discontinued when the temperature is 60 ºF and falling. Recycling operations shall not be performed when the weather is foggy or rainy, or when weather conditions are such that the proper mixing, spreading, compacting, and curing of the recycled material cannot be accomplished. Cold recycled pavement damaged by precipitation shall be reprocessed or repaired by methods approved by the Engineer, at the Contractor’s expense. The construction of cold recycled pavement will not be allowed from September 16 through May 14 unless otherwise approved. The Contractor’s Progress Schedule shall show the methods to be used to comply with this requirement.
406.04 Milling . The existing asphalt surfacing shall be cold recycled in a manner that does not
disturb the underlying material in the existing roadway. Adjacent recycling passes shall overlap at the longitudinal joint a minimum of 4 inches. The beginning of each day’s recycling operation shall overlap the end of the preceding recycling operation a minimum of 100 feet unless otherwise directed.
Source: Colorado Standard Specifications for Road and Bridge Construction, 2023 Edition. Pages 363–364 of 943.