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w <br /> SM <br /> asphalt may cover the water or clay film without directly <br /> adhering to the aggregate particle.' <br /> To ensure good adhesion between the asphalt and the aggregate or <br /> sand particle, moisture and clays are to be avoided. Thus, this <br /> technology has limited application for treating petroleum <br /> contaminated soils with high clay fractions and a high capacity <br /> for water retention. <br /> Integrity of Asphalt Pavement <br /> The suitability of asphalt paving mixes are judged based upon the <br /> following properties; <br /> o Stability - resistance to deformation; stability is <br /> measured in units of Hveems. <br /> o Durability - resistance to weathering, crushing, and <br /> degradation; partially dependent upon permeability <br /> o Flexibility - ability to conform to long--term <br /> variations in the base due to settling and the ability <br /> to bend repeatedly without fracture (fatigue <br /> resistance) <br /> o Skid resistance -- to allow reasonable traction in all <br /> weather conditions <br /> 0 <br /> Permeability lora permeabilities are desired to <br /> resist the impact of _weathering and permeability is an <br /> important factor in durability. <br /> o Workability - the ability to achieve a smooth finish <br /> when the pavement is placed and compacted in the road. <br /> The pavement stability is determined primarily by the friction <br /> between the aggregate particles, the viscosity of the asphalt <br /> mixture and the mix ratio of the asphalt to aggregate. Stability <br /> is enhanced by using aggregates with rough-textured surfaces and <br /> may also be influenced by particle size and gradation. For the <br /> Purposes of stability, the amount of asphalt should be minimized <br /> as too much asphalt will act as a lubricant and cause the mixture <br /> to flow. This is especially true for "critical" sand mixtures or <br /> aggregate mixtures containing a high percentage of :fines.' As <br /> seen in this study, a slight excess of asphalt in a critical <br /> mixture can reduce the pavement's stability. <br /> Durability is primarily dependent upon the aggregate/sand <br /> resistance to crushing, abrasion--and_weather-in <br /> g, and-the--- --- ----- <br /> aspha,lt's-resistance to weathering and a <br /> the impact of weatheringthe ging. t is assured that <br /> on particle will be minimal as long <br /> as it is coated with asphalt. The durability of the asphalt may <br /> f) be impacted by several chemical reactions. Reactions with may <br /> change the asphalt binder composition and thereby affect its <br />