Predicting Moisture-induced Damage to Asphaltic Concrete


Book Description

Virginia is one of seven state and federal agencies participating in a field evaluation of a stripping test method developed under NCHRP Project 4-8 (3), "Predicting Moisture- Induced Damage to Asphaltic Concrete." The test method is being used to evaluate the efficacy of the method in predicting the degree of stripping that will occur on a 1,000 ft. (300 m) test section constructed with an asphaltic concrete believed to have a tendency to strip. The degree of stripping of the pavement will be evaluated by visual observation of cores taken periodically and by pavement surveys. In the test method resilient modulus and indirect tensile tests are being performed on preconditioned and non-preconditioned specimens in predicting the potential stripping. The strength or stiffness loss resulting from vacuum saturation preconditioning is being used to indicate potential immediate stripping, and the strength or stiffness loss under a more severe accelerated preconditioning indicates potential stripping after a long period of time. The tests have predicted that stripping will occur over a long period rather than a short period. Tests on cores taken 12 months after construction have shown a minor amount of stripping.













Predicting moisture induced damage to asphaltic concrete


Book Description

The Virginia Department of Highways and Transportation is one of seven state and federal agencies participating in a field evaluation of a stripping test method developed under NCHRP Project 4-8(3), "Predicting Moisture-lnduced Damage to Asphaltic Concrete". In the Virginia portion of this field phase of the project, an evaluation is being made of the effectiveness of the method in predicting the degree of stripping that will occur on a 950-ft. (290-m) test section constructed with an asphaltic concrete believed to have a tendency to strip. The test method was used on specimens prepared in the laboratory and on cores taken immediately after construction of the test section in an attempt to predict the stripping susceptibility of the mix. On the basis of the results of those tests it was predicted that stripping would occur over a long period. Tests on cores being taken periodically show decreasing strength values that probably are a result of progressive stripping, that was very evident in cores taken at 22 months.










Implementation, Predicting Moisture Induced Damage to Asphalt Concrete Design Mixes


Book Description

Six aggregate sources from around the State of Montana were selected to represent various qualities of aggregate and asphaltic concrete. Resilient ('R') Modulus tests, maximum tensile split tests and immersion compression tests were performed on each source and compared for correlation. Specimens used for the resilient modulus and the maximum tensile split tests were subjected to severe temperature conditioning, representing several years of natural exposure. The resultant data indicates that the use of the maximum tensile split tests and the 'R' modulus test are not appropriate for use on a routine basis. The Montana Department will continue to use the immersion compression test for moisture susceptibility prediction.