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Title: Evaluating Adhesion Properties and Moisture Damage Susceptibility of Warm-Mix Asphalts: Bitumen Bond Strength and Dynamic Modulus Ratio Tests
Accession Number: 01373454
Record Type: Component
Record URL: Availability: Transportation Research Board Business Office 500 Fifth Street, NW Find a library where document is available Abstract: Through development and evaluation of the warm-mix asphalt (WMA) mixture design process, increased moisture susceptibility has been cited as one of the potential critical failure modes for WMA. Reduced production temperatures can affect the drying of the aggregate before mixing, the development of adhesion at the asphalt–aggregate interface, and binder stiffness. The objective of this research is to identify the significance of these factors and to define their relative contribution to mixture resistance to moisture damage. To evaluate the contribution of asphalt binder–aggregate adhesion, the bitumen bond strength (BBS) test was implemented on dry and moisture-conditioned samples. The effect of production temperature was simulated by heating aggregate substrates to hot-mix asphalt (HMA) and WMA temperatures before applying the asphalt binder. Furthermore, the effect of reduced binder stiffness resulting from lower production temperatures was considered through establishing two controls for mixture performance testing: a conventional HMA and a mixture prepared at WMA temperatures without WMA additives. The relevance of these factors was established through comparison with mixture performance as measured by the reduction in dynamic modulus, as a function of conditioning cycles. Mixture sample preparation allowed for consideration of residual moisture in aggregate that might have been associated with WMA and provided a control HMA sample prepared under standard conditions to establish a performance benchmark. Recommendations were made for incorporation of these new test methods into current WMA mixture design specifications. In summary, both BBS and dynamic modulus testing indicated that specific WMA additives could improve the mixture’s moisture resistance and could offset any negative effects from the reduced production temperatures on moisture susceptibility. Therefore, selecting appropriate warm-mix additives during the mix design process can help mitigate potential moisture damage associated with WMA.
Monograph Title: Monograph Accession #: 01454859
Report/Paper Numbers: 12-4331
Language: English
Authors: Alavi, Mohammad ZiaHajj, Elie YHanz, AndrewBahia, Hussain UPagination: pp 44–53
Publication Date: 2012
ISBN: 9780309223362
Media Type: Print
Features: Figures; References; Tables
TRT Terms: Uncontrolled Terms: Subject Areas: Highways; Materials; Pavements; I31: Bituminous Binders and Materials
Files: TRIS, TRB, ATRI
Created Date: Feb 8 2012 5:23PM
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