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PN <br /> Rgsgx, <br /> kerosene or naphtha solvent. These materials may <br /> be expected to contain, PNAH compounds originating <br /> = � from the heavy asphalt solute and are <br /> characterized by a high VOC content due to the <br /> solvent carrier. <br /> Medium curing (MC) liquid asphalts are produced by <br /> dissolving softer asphalt cements in a kerosene <br /> type solvent. These materials may also contain <br /> pVAH compounds, but in a lower concentration than <br /> the RC liquid asphalts, because they are derived <br /> from the lighter fractions of asphalt cement. <br /> These materials may also contain a high VOC <br /> content due to the solvent carrier. <br /> -- Slow curing (5C) liquid asphalts (or road oils) <br /> may be derived from distillation, being the <br /> fluxing <br /> lightest fraction of the asphalts, or by g <br /> the liglitest fraction .of the asphalt cements with <br /> lighter oils. These materials are most similar to <br /> residual fuel oils, which also are derived from <br /> the lighter- ends of the petroleum distillate (See <br /> Figure 1) . <br /> SC liquid asphalts are expected to be composed <br /> primarily of chain--type aliphatics rather than <br /> aromatic compounds. However, the potential for <br /> PNAH contaminants cannot be discounted and, <br /> because some PNAH compounds have been designated <br /> as potential car-cinogens, even trace <br /> concentrations may be of concern. The SC liquid <br /> -volatile or non-volatile, and <br /> asphalts are semi <br /> are therefore the potential for VOC emissions are <br /> a not a major concern. <br /> Asphalt emulsions ate produced by using <br /> surfactants to emulsify asphalt cements :n water. <br /> Anionic, cationic and non-polar asphalt emulsions <br /> are available. These materials may contain PNAH <br /> compounds depending upon the grade of asphalt <br /> cement from which they are derived. Emulsions are <br /> relatively non-volatile. <br /> ASPHALT PAVING MIXTURES <br /> paving mixtures typically are composed of aggregate and/ <br /> Asphalt p weight) . The <br /> or sand (90-95� by weight) and asphalt (5 -10 by g a <br /> - -- -- <br /> aggregate and/or sand is responsible for the primary load bearing <br /> propertiesr-while--asphalt--serves_as_�he__ bint and as a --- <br /> protective coating. The asphalt binder functions best-when t e -- <br /> - - <br /> aggregate/sand particles are "wetted" with asphalt. if the <br /> particle is coated with water or a clay film prior to mixing, the <br />