This report, NCHRP Report 268, and a companion report, NCHRP Report 269, "Paving with Asphalt Cements Produced in the 1980's," will be of special interest and value to individuals responsible for materials testing, mix designs, and construction of asphaltic concrete pavements. The findings of laboratory and field studies on the effects of asphalt cement properties on pavement construction operations and short-term performance are described in this report. These findings indicate that the physical properties of asphalt cements are likely to be more variable today than 20 years ago even though they remain within specification values. However, variations in other material properties and construction practices may mask the influence of this variation on pavement performance. The companion report is a field manual containing suggestiongs for making adjustments in materials selection, mix design, and construction operations to overcome the variations in asphalt cement properties that have been found to occur. The suggestions in the manual are based on field experience and thus are suitable for immediate implementation. (Author).
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