Pavements are subjected to different stresses during their design lives. A properly designed pavement will perform adequately during its design life, and the distresses will not exceed the allowable limits; however, there are several factors that can lead to premature pavement failure. One such factor is moisture sensitivity. AASHTO T 283 is the standard test used in the moisture susceptibility evaluation of asphalt mixtures, but the results of the test are not very representative of the expected behavior of asphalt mixtures. The dynamic modulus test measures a fundamental property of the mixture. The results of the dynamic modulus test can be used directly in the Mechanistic-Empirical Pavement Design Guide (MEPDG) and are considered a very good representation of the expected field performance of the mixture. Further research is still needed to study how the dynamic modulus results are affected by moisture. The flow number test was studied in previous research as a candidate test for moisture-susceptibility evaluation, but the results of that research were not favorable. This research has four main objectives. The first objective of this research is to evaluate the usefulness of the dynamic modulus and flow number tests in moisture-susceptibility evaluation. The second objective is to compare the results to those achieved using the AASHTO T 283 test. The third objective is to study the effect of different methods of sample conditioning and testing conditions. The fourth objective of the research is to study the variability in the test results.

Even though moisture sensitivity of Hot Mix Asphalt (HMA) mixtures has been recognized as a major form of distress in asphalt concrete pavements since the advent of asphalt paving technology, the mechanism of this problem has not been clearly identified until now. However, it has been agreed that it can be characterized by the loss of adhesive bond between the asphalt binder and the aggregate or by a softening of the cohesive bonds within the asphalt binder, both of which are due to the action of loading under traffic in the presence of moisture. The evaluation of Hot Mix Asphalt moisture sensitivity has been divided into two categories: visual inspection test and mechanical test. However, most of them have been developed in pre-Superpave mix design. This research was conducted to develop a new test protocol which can overcome the problems of the current procedures and to evaluate the possibility of using the Nottingham Asphalt Tester (NAT) in the resulting procedure.

Explores whether combining the environmental conditioning system with the simple performance test would provide a superior procedure for determining the moisture susceptibility of hot-mix asphalt (HMA).

It has been extensively documented since the late 1970's that moisture damage occurs in hot mix asphalt (HMA) pavements. A variety of test methods are available that test an HMA's ability to resist moisture sensitivity. There are also some test methods that look at an asphalt binder's moisture susceptibility. The current test method for detecting moisture sensitivity in HMA is American Association of State Highway and Transportation Officials (AASHTO) T283: Resistance of Compacted Bituminous Mixture to Moisture-Induced Damage. Inclusion of this test method in Superpave did not consider the change in specimen size from 100mm to 150mm nor difference in compaction method. The procedures in AASHTO T283 consider the loss of strength due to freeze/thaw cycling and the effects of moisture existing in specimens compared to unconditional specimens. However, mixtures do not experience such a pure phenomenon. Pavements undergo cycling of environmental conditions, but when moisture is present, there is repeated hydraulic loading with the development of pore pressure in mixtures. Thus, AASHTO T283 does not consider the effect of pore pressure, but rather considers a single load effect on environmentally conditioned specimens. This report develops moisture susceptibility procedures which would utilize repeated loading test devices (dynamic modulus or asphalt pavement analyzer) of specimens in saturated conditions and be compared to unconditioned specimens in a dry test environment. In addition to HMA mixture testing, a modified dynamic shear rheometer will be used to determine if an asphalt binder or mastic is moisture susceptible. Moisture susceptible criteria was developed using the dynamic complex modulus, asphalt pavement analyzer, and dynamic shear rheometer. Evaluation of AASHTO T283 for 150mm Superpave Gyrtaory compacted specimens is also detailed in this report along with a new criterion.

New developments in asphalt with bio-oil, rubber and polymer componentsEmpirical data and models on binders, aggregates, RAP, WMA, HMA for pavementSpecial section on asphalt paving research in IndiaFully-searchable text on CD-ROM (included) The latest volume of the AAPT series features over two dozen research presentations devoted to the chemistry, engineering, modeling and testing of asphalt materials and processing. Developments in the use of components like bio-oil are discussed, as are strategies for testing asphalt components for wear and durability at low and high temperatures. The book offers new data on the performance of reclaimed/recycled materials in asphalt paving. A special section focuses exclusively on discussions of binder modifications. The CD-ROM displays figures and illustrations in articles in full color along with a title screen and main menu screen. Each user can link to all papers from the Table of Contents and Author Index and also link to papers and front matter by using the global bookmarks which allow navigation of the entire CD-ROM from every article. Search features on the CD-ROM can be by full text including all key words, article title, author name, and session title. The CD-ROM has Autorun feature for Windows 2000 with Service Pack 4 or higher products along with the program for Adobe Acrobat Reader with Search 11.0. One year of technical support is included with your purchase of this product.

The premier guide for understanding the causes and treatments for moisture damage of HMA (hot mix asphalt), this manual helps technicians learn test methods to evaluate damage potential, treatments to prevent moisture damage, and best practices to minimize moisture damage in HMA pavements.