3.1 Recycling of deteriorated asphalt pavements is being used as a routine method of maintenance and rehabilitation. Utilization of existing materials as the major component of this procedure may yield benefits in quality, economy, and preservation of natural resources. Recycling takes many forms; hot, cold, in-situ, central plant and surface. This practice may be used for various recycling methods.

3.2 This practice describes emulsified recycling (ER) agents as belonging to three groups; ER-1, ER-2, and ER-3 as shown in Table 1. The range of recycling methods demands several emulsified recycling agents. The groups should provide adequate freedom of selection for most recycling methods.

3.2.1 ER-1 is a material whose main function is to rejuvenate aged asphalt. The material is a petroleum derivative, and highly compatible with asphalts. It is classified by viscosity.

3.2.2 ER-2 and ER-3 are materials that combine rejuvenators and asphalt components in one emulsified asphalt. These soft residues are classified by low temperature penetration after aging. They are typically used in recycling where there is an increased demand for asphalt as when new aggregates are added, or where immediate cohesiveness is desired.

3.3 The choice of ER will be determined by the properties of the asphalt binder in the aged pavement, the methods of recycling planned, the amount, if any, of new aggregates, and other design needs.

1.1 This practice identifies emulsified petroleum products that may be used as recycling agents in recycled mixes. These materials are classified by viscosity or by low temperature penetration after aging.

1.2 This practice addresses emulsified materials designed specifically for use in recycling. The use of emulsified materials for recycling shall not be limited to this practice. For instance, the emulsified asphalts specified in Specifications D977 and D2397 may be used.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.