Change No. 189NS (Final Approval 6.16.2011) 203-11 ASPHALT RUBBER HOT MIX (ARHM) WET PROCESS . 203-11.1 General. Asphalt Rubber Hot Mix shall consist of a mixture of paving asphalt, asphalt modifier, crumb rubber modifier (CRM), and aggregate mixed in a central mixing plant. 203-11.2 Materials. The Contractor shall submit test reports and Certificates of Compliance, conforming to 4-1.5, for the paving asphalt, asphalt modifier, and CRM to be used. In addition, W hen requested by the Engineer, the Contractor shall also submit samples of the tested material. along with the Certificate of Compliance. 203-11.2.1 Paving Asphalt. Paving asphalt used for asphalt-rubber shall be PG 64-16, conforming to 203-1. and shall be modified with an asphalt modifier. Performance graded paving asphalts other than PG 64-16 may be used if so specified in the Special Provisions. 203-11.2.2 Asphalt Modifier . The asphalt modifier shall will be a resinous, high flash point, aromatic hydrocarbon compound and shall conform to the requirements shown in Table 203-11.2.2 (A). The asphalt modifier may be eliminated if approved by the Engineer. TABLE 203-11.2.2 (A) REQUIREMENTS FOR ASPHALT MODIFIER Property ASTM Test Method Value Flash Point, C.L.O.C., °F (°C) D 92 405 (207) min Viscosity, cSt @ 212°F (100°C) D 445 X ± 3* Molecular Analysis Asphaltenes, percent by mass Aromatics, percent by mass D 2007 D 2007 0.1 max 55 min * The symbol “X” is the viscosity of the asphalt modifier the Contractor proposes to furnish. The value “X” which the Contractor proposes shall be between the limits of 19 and 36 and shall be submitted in writing to the Engineer. Any proposed change requested by the Contractor in the value “X” shall require a new asphalt-rubber binder design. 203-11.2.3 Crumb Rubber Modifier (CRM). The material CRM shall consist of a combination of scrap tire CRM and high natural CRM meeting the requirements of this subsection . Scrap tire CRM shall consist of ground or granulated rubber derived from any combination of automobile tires, truck tires or tire buffings. The high natural CRM shall consist of ground or granulated rubber derived from materials that utilize high natural rubber sources. Whole scrap tire CRM shall be derived from whole scrap tires generated within the State boundaries of the user agencies. The Certificate of Compliance required in 203 - 11.2 shall contain a statement confirming conformance with this requirement. The high natural CRM may consist of blended CRM. CRM shall be ground or granulated at ambient temperature. Cryogenically produced CRM particles which can pass through the grinder or granulator without being ground or granulated shall not be used. Cryogenic separation, if utilized, shall be performed separately from and prior to grinding or granulating. Steel and fiber separation may employ any method CRM shall not contain more than 0.01 percent of wire by weight and shall be free of all other contaminants, except fabric. Fabric shall not exceed 0.05 percent by weight of CRM. A Certificate of Compliance certifying these percentages shall be furnished to the Engineer. CRM shall be dry and free-flowing and not produce foaming when combined with the blended paving asphalt and asphalt modifier mixture. Calcium carbonate or talc may be added up to a maximum of 3 percent by weight of CRM to prevent CRM particles from sticking together. The CRM shall have a specific gravity range from 1.1 minimum to 1.2 maximum as determined by ASTM D 297. Scrap tire CRM and high natural CRM shall be delivered to the production site in separate bags and shall be sampled and tested separately. Scrap tire CRM material shall conform to the following chemical analysis requirements shown in Table 203-11.2.3 (A ).
ASPHALT RUBBER HOT MIX (ARHM) WET PROCESS
Jun 20, 2023
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