PRODUCTION AND CONSTRUCTION ISSUES FOR MOISTURE SENSITIVITY OF HOT-MIX ASPHALT PAVEMENTS

Today we are demanding more from our pavements than ever before. As we continue our efforts to design and construct hot-mix asphalt (HMA) pavements that perform better and last longer, we must consider all of the factors involved in the ultimate performance of the pavement. Moisture-induced damage within HMA has been described as a national issue leading to the decreased life of our nation's roadways. As we consider the nature of materials and specifications across the country, it is important to understand the impact that both material production and construction can have on the ultimate performance of the HMA pavement in the field. During the design of most HMA mixtures, tests to evaluate the potential for moisture-induced damage are conducted. For most states in the United States, AASHTO T283, or a modified version, is used for this purpose. If a designed mix meets the requirements of this test, it is assumed that the mix will perform in the field with respect to resistance to moisture damage. However, if the designed mix is not produced and constructed properly, moisture damage can still occur as a result of construction deficiencies. There are a number of production- and construction-related issues that can affect the ability of an HMA pavement to resist moisture damage. Factors from the handling of stockpiles through placement and compaction of the HMA on the roadway can affect the potential for moisture damage in the field. In fact, mixes that are marginal with respect to resistance to moisture damage that are well constructed on the roadway may perform better than mixes with a low potential for moisture damage that are poorly constructed. Therefore, the proper production and construction of HMA pavements is vital to providing roadways that will perform up to and beyond their design lives. This objective of this paper is to highlight various production and construction issues that can increase the potential for moisture-induced damage in HMA pavements. Also, good production and construction practices are discussed to help decrease the potential for moisture damage in HMA pavements.